PROCESS AND EQUIPMENT CAPABLE TO ACHIEVE ZERO-ENERGY HEATING, VENTILATION, AIR CONDITIONING OPERATION

Abstract

Process and equipment for managing air properties allowing to achieve Zero-Energy HVAC operation allowing 24/7 air recycling capability with up to 100% re-feed capability independent of internal and external factory air conditions with air humidity controller or with dedicated air humidity controllers for both factory air and process air.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of International Patent Application PCT/SG2016/050370, filed Jul. 29, 2016, which claims priority to and the benefit of the filing of Singapore Patent Application No. 10201505956Y, filed on Jul. 29, 2015, and the specification and claims thereof are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention (Technical Field)

The present invention outlines new air property management related systems such as HVAC (Heating, Ventilation, Air Conditioning) systems that can be used to remove heat from air exiting a room or factory or production process having an elevated temperature without the need for the typical energy requirements associated with existing HVAC technology where significant amounts of energy are required to chill within the HVAC cooling and de-humidification process. With conventional HVAC chilling technology employing chilling coils, the process dwell time (time the air spends in the coil area) is very short due to the small size of the coil technology and as such, the coils must be chilled to a low temperature in order for the coil process to function adequately. Also with conventional HVAC coil technology, the coils also control the air humidity by reducing their temperature to below the dew point of the air passing through the coil. In both these instances, the energy required to chill the coils to such as low level is significant and requires large compressor systems and other ancillary items such as cooling systems to achieve the lower coil temperatures required for this process to operate. The present inventions are directed towards a new process using heat exchanger technology with the process having an extended dwell time as well as having large contact areas for the air within the heat exchanger, as well as the respective equipment.

The present invention allows full air recycling independent of external air climate (humidity and temperature) and also allows factories to expel air outside of the factory if desired without comprising final filter stages and also reducing main system fan energy requirements.

Production sites, such as hygiene factories producing hygiene products, such as diapers, feminine pads, bed pads, tampons, tissue, wipes, and the like, as well as materials useful for such products like tissue and non-wovens factories, as well as textile, carpet and garment factories typically extract air from their production processes and production areas. This extracted air is typically used for production processes such as core-forming, fibre making, holding materials, products and/or assemblies onto conveyor systems as well as removing dust from the production area. The temperature of air being removed from the production process and/or factory typically increases as a result of many factors such as ancillary production systems such as (i) hot-melt gluing systems and non-woven extruder heads, (ii) the passing of air through vacuum conveyors which run at an elevated temperature, (iii) passing the air through ducts at high speed and (iv) passing the air through process fan and main fan systems operating at an elevated temperature. For example, whilst ambient factory air can be at a temperature of about 25° C., air exiting a baby diaper convertor process typically increases to about 45° C. and in some instances has been recorded as high as about 88° C. or even more. For non-wovens production convertors and air-laid convertors temperatures can be far higher. For factories that do not recycle the air, this air is exhausted outside of the factory but the air being removed from the factory needs to be replaced. As such, a diaper convertor requiring for instance 50 10³ m³/hr of air and expelling this air outside of the building requires 50 10³ m³/hr of new air to be replaced within the factory. For factories operating with multiple production systems, this airflow can be significant. Modern state-of-the-art factories today filtering the air being extracted from their production systems to HEPA (High-efficiency particulate arrestance, high-efficiency particulate arresting or high-efficiency particulate air) quality standards can safely recycle air back into their factory. Recycling the HEPA filtered air and returning this air directly within the factory means new air does not have to be conditioned and brought back into the factory meaning vast HVAC operational costs can be saved. To date however, recycling air of elevated temperatures presents challenges even if the air has been filtered to HEPA quality. During winter periods for instance, for factories located in northern or southern hemispheres the elevated temperatures can be of benefit as this heated air can be used to heat the factory during the winter period, however, for factories located close to the equator or factories located in northern or southern hemispheres during summer periods, this elevated air temperature has no value to many factories and often creates significant issues. As such, factories typically have to understand and balance the effects of either using energy to chill the recycled air via HVAC systems back down to a desirable level, or, expelling this air outside the factory and condition new air entering the factory that also requires energy as the temperature and humidity of this new air entering the factory needs to be modified to factory requirements. HVAC or air property management systems typically calculate the cheapest option for the factory and automatically balance the amount of recycled air, the actual amount depending on process air temperature, external air temperature and external air humidity and energy prices. For multi-stage filtration processes, to date, air exiting the filter and expelled externally to the factory typically passes through all filtration stages.

Adiabatic cooling processes are used in many air systems and essentially have the capability to chill air to a defined point (referred to as the wet-bulb air temperature). This process is very similar to the human body's cooling system where sweat evaporates causing a cooling effect and is essentially an energy free cooling process in that no external energy is required and works on the evaporation cooling process.

Using an adiabatic cooling process in a factory is possible and, in, many locations around the globe, adiabatic cooling process are used, however, these processes have by default undesirable effects in that the air humidity significantly increases, both the relative humidity (RH) as the absolute water content. Increasing air humidity is in almost all instances not desirable, as this increases the “feel” temperature of the air due to the higher humidity levels and reduces the quality of the work environment for factory workers. Furthermore, in most factory production processes increased humidity is also not desired particularly in the hygiene sector where SAP (super absorbent polymer) is used. Materials such as metal corroded at a faster rate, dew points are reduced allowing condensation to easily occur, and, processes such as hygiene production processes that process moisture sensitive materials such as SAP have significant production issues when operating at a higher air moisture level and many sub related systems start to fail (screens, cyclones, filter media etc.)

BRIEF SUMMARY OF THE INVENTION

In a first aspect, the present invention is an air property management system (200) in the manufacturing of hygiene products in a manufacturing set up (210), such as of baby and adult incontinence absorbent articles, feminine hygiene articles, and materials adapted to be used in such articles, preferably selected from the group consisting of nonwoven, films, or composites thereof.

The manufacturing set up (210) comprises: a) A production area (215) comprising walls (217), which are adapted to separate the production area (215) from the external ambient environment (205). The manufacturing room comprises space for the manufacturing equipment (230) of the articles, preferably a multiplicity of the manufacturing equipment, and for operators (236). The manufacturing room further comprising aerial environment (220). b) At least one manufacturing equipment (230) of the articles in the manufacturing room, whereby the manufacturing equipment comprises a housing (235) separating process air (240) from the manufacturing room aerial environment (220). Preferably, the housing is integral with sound retarding housing. The manufacturing equipment further comprises article forming elements (245) inside the housing, which are adapted to change at least one of the properties of the process air of from said manufacturing equipment aerial environment properties (250), these properties being selected from the group consisting of temperature, moisture content, dust content, and pressure.

The article forming elements (245) are preferably selected from the group consisting of hot melt application systems, ultrasonic systems, separation systems, defiberization systems, separation systems, web handling drive system, web handling friction systems. c) An air treatment system (260), preferably a HVAC system. d) Duct work (270) adapted to connect the manufacturing equipment housing (235), the production room environment (220) and the external ambient environment (205) to the air treatment system (260).

The air treatment system (260) comprises an indirect heat exchange system adapted to transfer energy from the external ambient air (205) to the aerial manufacturing environment (220) or the process air (240), most preferably without mixing of the energy transferring air streams.

Preferably, the indirect heat exchange system is an adiabatic heat exchange system.

Optionally, the air property management system further comprises one more elements selected from the group consisting of one or more temperature adjustment element(s) (282) preferably indirect heat exchange elements, preferably selected from the group consisting of:

• • cooling elements preferably cooling water at ambient temperature;
  • heating elements;
  • energy exchange elements between other elements connected via the duct system;

Closing valves (288) in the duct work, preferably adapted to be closed, more preferably automatically, in case of an opening of the housing.

a fan element (280);

an air humidity adjustment element (286) adapted to allow increase or decrease of the absolute humidity (water content) of the air;

a dust reduction system (284), preferably filter, more preferably HEPA filter;

an automated control system for adjusting process settings according to production processing variables as well as external ambient air conditions.

Optionally, an air flow distribution system comprises valves (288), side ducts and optionally further air treatment systems so as to provide predetermined air flows to various parts of the system, preferably to different article forming elements.

Preferably, the indirect heat exchange system is a multi-way heat exchanger, preferably comprising multiple layers consisting of a 3D surface structure of materials separating airflows within the heat exchanger, and more preferably of the high-surface area honeycomb type.

Optionally, the indirect heat exchange system is adapted to match dimensions of a standard ISO 668 container, whereby preferably the housing serves multiple purposes of providing structural integrity to achieve ISO 668 standards and to support the material layers of the heat exchanger.

In another aspect, the present invention is a process for the management of air properties in the manufacturing of products in a manufacturing set up, whereby the products are preferably selected from the group consisting of baby and adult incontinence absorbent articles, feminine hygiene articles, and materials adapted to be used in such articles, preferably selected from the group consisting of nonwoven, films, composites thereof.

The process for the management of air properties comprises the following steps:

• • Providing a manufacturing set up (210) comprising a) a manufacturing room (215) comprising (i) walls (217) adapted to separate the manufacturing room from the external ambient environment (205), and further space for the manufacturing equipment (230) of the articles, preferably a multiplicity of manufacturing lines, and for operators (236) and (ii) aerial manufacturing environment (220); b) manufacturing equipment (230) of the articles in the manufacturing room, the manufacturing equipment comprising (i) a housing (235) separating a manufacturing equipment aerial environment (240) from the manufacturing room environment (220), whereby the housing is preferably integral with sound retarding housing, (ii) article forming elements (245) inside the housing adapted to change at least one of the air properties (250) in the manufacturing equipment environment, the properties being selected from the group consisting of temperature, moisture content, dust content, pressure. The article forming elements (245) may be selected from the group consisting of hot melt application systems, ultrasonic systems, separation systems, defiberization systems, separation systems, web handling drive system, web handling friction systems; c) an indirect heat exchange system (260); d) duct work (270) adapted to connect the manufacturing equipment housing (235), the manufacturing room environment (220) and the external ambient environment (205) to the indirect heat exchange system (260).
  • Changing the properties of the manufacturing equipment aerial environment (240) by operating the article forming elements;
  • Collecting process air from the manufacturing equipment aerial environment (240) and submitting it to a pressure differential to create air flow in the duct work; Transferring the process air from the manufacturing equipment aerial environment (240) to the indirect heat exchange system;
  • Optionally collecting room air from the aerial manufacturing environment (220) and transferring it to the indirect heat exchange system;
  • Treating the process air of the room air, if present, by exchanging energy of with ambient air in an indirect heat transfer, preferably an adiabatic heat transfer, such that the content of ambient air in the air stream leaving said heat exchanger is less than 50%, preferably less than 80%, more preferably less than 10%, even more preferably less than 1% and most preferably essentially zero.

In this process for the management of air properties, there is essentially no mixing of the process air and the room air, if present, with the ambient air, whereby preferably the heat exchange between the ambient air and the processing air is an adiabatic heat exchange.

Optionally, in the process for the management of air properties the treated process air and room air, may further be submitted to one or more of the steps selected from the group consisting of: further heating or cooling; adjusting water content by adding or removing moisture; reducing dust level; creating further pressure differential; interrupting the air flow of the processing and the treated air by stop valves upon opening the walls of the manufacturing equipment; collecting air from more than one manufacturing equipment; directing more than one air flow to the indirect heat exchange system, preferably by operating a multi-way heat exchanger; diverting the air flow of treated air towards two or more endpoints in the manufacturing room environment or within the equipment environment.

In another aspect, the present invention is a heat exchanger where at least one incoming airflow stream is connected to process-air exiting a production process, which may be a hygienic, non-wovens or air-laid process or fibre or food, which may be with elevated air temperature. The heat exchanger may be at least a two-way heat exchanger. One incoming airflow stream may be connected to ambient air, wherein optionally the heat exchanger may be at least a two-way heat exchanger. The ambient air may be treated with an adiabatic cooling process. Optionally, the ambient air is exited back to ambient. The heat exchanger may be connected to a production process for the making of hygienic products or materials therefore, such as non-woven or air-laying processes or fibre making processes. An incoming airflow stream may be connected to both ambient air and factory air.

The heat exchanger may be at least a two-way heat exchanger. The ambient air may be treated with an adiabatic cooling process. Optionally, the ambient air is exited back to ambient. The heat exchanger may be connected to a production process that is a hygienic, non-wovens, air-laid process, fibre making process.

In a further aspect, the present invention is a singular production process or multitude of production processes, enclosed with a housing to separate air of differing properties like temperature, humidity, pressures, or dust levels for the manufacturing process as compared to the manufacturing room environment. Preferably the housing may serve as a sound reducing or retarding means. A dedicated humidity control process may be used to control air humidity levels within this housing. Optionally, the conditioned air within this housing can be controlled by secondary humidity control process to boost capacity until pre-set moisture levels have been reached, e.g. during start-up periods. The booster humidity capability may come from humidity control processes that process the factory air that is external from the air enclosed with a housing. Optionally, when the housing is opened, valves may close on the ducting working connected to the housing to prevent air of the manufacturing room environment from entering the ducting.

In a further aspect, the present invention is a singular production process or multitude of production processes, that utilises air within this production process, where the air exiting the process is filtered and sent back to the production process in a form that the returning air re-enters the production process. The returning air may re-enter the production process wherein the returning air volumes are similar to air process volumes within +/−90% variance. The returning air may re-enter the production process within multiple points within the process to reduce cross air flow currents within the multitude of production processes.

In yet a further aspect, the present invention is a singular production process or multitude of production processes that utilises air within this production process, where the air exiting the process is filtered and sent back to the production process via a heat exchanger.

In yet a further aspect, the present invention relates to a heat exchanger comprising multiple layers of materials separating air flows within the heat exchanger where the layers are contained within a shipping container confirming to ISO 668 shipping container standards with little or no modification. The multiple layers may exhibit a 3D surface structure of materials separating airflows within the heat exchanger where the layers are contained within a shipping container confirming to ISO 668 shipping container standards with little or no modification.

Optionally, the shipping container housing may serve multiple purposes, such as providing both structural integrity to achieve ISO 668 standards and to support the material layers of the heat exchanger.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The accompanying drawings, which are incorporated into and form a part of the specification, illustrate one or more embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating one or more preferred embodiments of the invention and are not to be construed as limiting the invention. In the drawings:

FIG. 1 A to H outline exemplarily and schematically various production factory set ups;

FIG. 2 A to D depict schematically various air management systems according to the present invention;

FIG. 3 A to C depict various more detailed views of the filtration and heat exchanger system, as may be suitable for the present invention;

FIG. 4 A to G depict further detailed views of the heat exchanger system suitable for the present invention; and

FIG. 5 A to D depict further details of an exemplary a diaper convertor platform.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to manufacturing set-ups or factories, which require for a good operation active management of the air properties. Whilst there are many types of manufacturing operations that have such requirements, a particular manufacturing set ups for producing hygiene products are particular sensitive to uncontrolled air properties, among others for hygienic reasons but in particular since the introduction of superabsorbent polymers also to allow smooth operation. Whilst such facilities used to operate without any HVAC capability, developments covered the introduction of HVAC capability, air recycling capability, optionally with valve systems to control the amount of recycled air entering the factory, and also heat exchanger technology. The present invention builds on such developments.

Combining this adiabatic cooling process with a heat exchanger (two-way or a multi-way exchanger) allows the humid air exiting the adiabatic cooling processes to remain separated from the air exiting the production process thereby not having any negative effects on the factory air.

Further embodiments of this invention are to return the recycled air back to the convertor process and not back into the factory air that is common today. With more and more production systems having higher sound emission criteria and with this trend most likely to continue, most production equipment are fully enclosed with sound retarding housing. This sound retarding housing can also be used to adequately separate the factory and process air. In the scenario where filter exhaust air is being returned to the production system, process air remains separated from factory air, and as such both air streams can operate at different temperature levels and moisture levels. Being able to run both air streams at separate temperature and moisture levels has distinct advantages for the end-user that is described herein below.

Further performance enhancements to the process are further described herein. The majority of hygiene factories operate at positive pressure versus ambient conditions, where new fresh air is injected into the air handing process to provide this positive pressure, but also to introduce fresh air into the factory or the manufacturing set-up that is a very important design feature of any well design HVAC system. A well designed HVAC system typically exchanges/replaces the air about 10 times per hour, and this air which is continuously being re-circulated has new fresh conditioned ambient air from outside injected into this air stream at values of around ten percent. As this newly injected air enters the process and factory, air within the factory is typically vented to the environment and the energy invested to heat, chill or de-humidity this air is lost. Further embodiments of this invention are to reduce the percentage of air exiting the factory, and to divert this air to an adiabatic cooling processes thereby reducing the wet-bulb temperature further.

For explanatory and exemplary purposes, a diaper factory located close to the equator is considered that is recirculating air at ten air changes per hour whilst adding 10% of newly conditioned fresh air from the HVAC system back into this air stream, whereby this additional air being pumped into the factory is exiting the factor via doors, windows, air vents etc. Assuming for such a scenario external air temperature at 32° C. with 65% relative humidity with air pressure at 1011 millibar, the wet-bulb temperature is at 26.2° C., whilst the dew point is at 24.1° C. Taking this external factory air at 32° C. and passing it through the two-way heat exchanger and then back-out of the heat-exchanger exiting outside of the factory to an area where this hotter air will not be sucked back into in inlet ducting means internal factory air and external factory air are not mixed. With the process air exiting the diaper production process at a temperature of 46.5° C., remaining in the factory and passing this air also through the two-way heat-exchanger and then exiting back inside of the factory reduces the air stream temperature without changing the relative humidity of this internal air stream. In an ideal process the production process at a temperature of 46.5° C. would be reduced to 32° C. however, due to inefficiencies in the heat exchanger process and adiabatic cooling process, a value of around 34.4° C. can be achieved.

Comparing this to an adiabatic cooling processes to chill the external factory air entering the heat exchangers, this air stream originally at 32° C. can be chilled down to 28.3° C. prior to entering the heat exchanger. This allows the air that was previously exiting the heat exchanger at 34.4° C. to be reduced to 28.3° C.

If now a proportion of the conditioned air, that was previously exiting the building, is fed into the incoming external factory air stream prior to the adiabatic cooling processes, say 80% of the overfeed air-flow thereby still allowing the factory to be pressurized increases the efficiency of the adiabatic cooling processes. The wet-bulb temperature that was previously at 26.2° C. is reduced to 24.1° C., meaning, the previous factory air-flow stream that was chilled to 28.3° C. with the standard adiabatic cooling processes can now be chilled down to 27.2° C., essentially with no additional energy requirements.

If the air flow exiting the heat-exchanger and going back into the factory is returned directly to the process as was mentioned earlier, then, this air stream can operate at a higher temperature without increasing the factory room environment, e.g. for the operators.

If a close circuit air-flow used for process air and this airstream becomes separate to factory air, the heat exchanger can be further split, in that internal factory air can also be passed through the heat exchanger and exit back into the factory. Further improvements to this would be to divert all external air-flows (vertical flow in cross flow heat exchanger and parallel flow in parallel flow heat exchanger and counter flow in counter flow heat exchanger) from the overfeed adiabatic cooling process into this zone of the heat exchanger to further enhance performance.

Considering again the above discussed diaper factory scenario and assuming the same adiabatic cooling processes to chill the external factory air entering the heat exchangers, then the external air stream originally at 32° C. can be chilled down to 28.3° C. prior to entering the heat exchanger, the heat exchanger would then essentially cool the hot production air circuit from 46.5° C. to 34.4° C. And as part of the heat exchanger would be used to chill internal factory air, the hot production air circuit cannot reach 34.4° C. but can reach 36.5° C.

As this air stream in closed loop and does not come into contact with the factory room air, this has no negative effect on the factory environment and system, provided that the ductwork has sufficient heat insulation. Assuming again, that in the heat exchanger 80% of the overfeed air-flow are fed back through the heat exchanger prior to it exiting the building. Assuming further an adiabatic cooling process and that the factory room environment exhibits 48% relative humidity at 25° C. at 1011 millibar, then a theoretical wet-bulb temperature of 18.42° C. can be achieved via the adiabatic cooling process. With inefficiencies in the adiabatic cooling process and the heat exchanger, the theoretical temperature of 18.42° degrees C. cannot be reached however output temperatures of about 20° C. can be achieved. With the factory room at 25° C., this lower temperature can be used to off-set heat loading that is added to the factory space through items such as glue tanks, and heat being expelled from the convertor.

The above described executions do not control air-humidity within the factory and as such, further embodiments are preferred to combine hygiene production processes with stand-alone air moisture control systems to maintain factory room air at a pre-set level. The separate control of process air and factor air allows the factory air to be maintained at an air humidity level most suited for humans, whilst the process air can be maintained at a humidity level most suited for the process. In most instances, the process air humidity would be very dry which further reduces cleaning effort and also reduces and even eliminates process issues such as SAP screen blinding on core-laydown processes, as well as it gives significant longer life expectancies of filtration media.

Further embodiments of the present invention are to combine the heat-exchanger frame-work with a frame-work that corresponds to shipping container dimensions for transportation processes.

Even further embodiments of the present invention include honeycomb profiles within the heat exchanger rather than conventional fin/plate technology. A heat exchanger made from honeycomb profiles has a high strength profile thereby allowing a thinner metal profile to be used. Furthermore, automatic honeycomb production methods allow a combine structure to be made that require little or no assembly effort hereby allowing the heat-exchanger to be produced at a more attractive cost for the end-user.

Further embodiments of this invention are to equip the outer interface of the heat exchanger with a common control interface that allows a plug & play common interface with other ancillary devices such as fan, filtration and HVAC equipment.

Further embodiments to this invention are to incorporate air humidity control devices within the total machine assembly.

Further embodiments of the present invention are to combine channels within the heat exchanger to allow water flows such as water that has been chilled or heated using geo-thermal energy. With the two-way heat exchanger having a high surface area and being an efficient means to change air temperature with low pressure drop, using geo-thermal energy to change the heat exchanger plates allows air temperatures to be modified further without the pressure drops that are associated with incumbent HVAC coil technology. This technology is of particular benefit in sandy regions such as Saudi Arabia where drilling costs are very low and as such the installation of geo-thermal ground pipes is also very low. For this particular usage, further embodiments to this invention are to combine channels within the heat exchanger to allow water flows such as water that has been chilled or heated using solar energy. With the two-way heat exchanger having a high surface area and being an efficient means to change air temperature with low pressure drop, using geo-thermal energy to change the heat exchanger plates allows air temperatures to be modified further without the pressure drops that are associated with incumbent coil technology.

Further embodiments of the present invention are to use the elevated air temperature of the closed circuit system in secondary drying processes. This higher air temperature combined with low humidity levels make this an ideal drying medium. This can for instance be used for the making curly fibers on-line where a significant drying load and heat is required.

Further embodiments of the present invention are to install additional valve technology in the filter process. To date, many filter processes consist of multiple filtration stages. In these processes, air exits the filter after the HEPA stage, however, if the air is exiting the factory to an external environment, then, it is not preferred to pass this air through a HEPA air filter as this requires further energy in the main system fan to pull the air through the HEPA filter media, and, the HEPA filter media has a reduced life span, also adding costs to the end-user on top of the higher energy costs. Installing a valve prior to the HEPA filter media allows factory exhaust air to exit the external environment prior to entering HEPA filter media, whilst, air being recycling back into the factory passes through the HEPA filter media prior to entering the factory.

A well-designed HVAC system typically exchanges/replaces the air about 10 times per hour, and this air which is continuously being re-circulated has new fresh conditioned air from outside injected into this air stream at values of around ten percent. As this newly injected air enters the process and factory, air within the factory is typically vented to the environment and the energy invested to de-humidity this air is lost. Further embodiments of this invention are to reduce the percentage of air exiting the factory, and to divert this air back into the adiabatic cooling processes thereby reducing the wet-bulb temperature further.

Considering for explanatory and exemplary purposes, a diaper factory located close to the equator, that is recirculating air at ten air changes per hour whilst adding 10% of newly conditioned fresh air from the HVAC system back into this air stream, whereby this additional air being pumped into the factory is exiting the factor via doors, windows, air vents etc.

Whilst the figures used for the explanation of the present invention outline cross-flow heat exchanger it should be noted that equivalent executions can also be used, such as parallel flow heat exchangers and counter flow heat exchangers or combinations of any type.

Without wishing to limit the present invention by the following, exemplary executions of the hygiene product manufacturing environment are described by referring to the figures to allow a better understanding.

At the onset of many production technologies, production started in factories that had no HVAC systems. A typical example of this is in FIG. 1A where a factory is depicted where production systems operate where these production systems are connected to filter system. Air is exhausted outside of the factory where the filters main purpose is to prevent environmental damage. FIG. 1A outlines a production factory (100) with no HVAC capability with the factory production area (101) and several of a production system (105) within the factory production area (101). An air filter system (110) is shown to be connected to the production system (105) and duct work (115) is connecting the outlet of the filter to the exterior ambient environment of the factory to where the air is expelled.

As the factories evolved, many factories migrated to HVAC systems, enclosed their building and slightly pressurised the building. With active air circulation and a regulated fresh air injection into the factory many advantages were gained. Workers were able to work in a comfortable work environment, with no significant temperature or humidity changes. In hot climates, staff attrition rates dropped and staff morale was boosted. Factories requiring a clean environment, such as food and hygiene production had the added benefit that insect and other contamination risks were eliminated as the build was sealed and air entering into the factory was filtered. A typical example of this is in FIG. 1B where a factory is depicted where a standard HVAC system is used. FIG. 1B depicts the same elements as FIG. 1A, however, this factory configuration has HVAC capability with chillers (120) and with AHUs (air handling units, 125), from where air re-enters the factory via the duct work (130) connecting the AHUs to the interior of the factory respectively the factory production area.

As production systems evolved further, production speeds increased, the number of processes increased and air volumes also increased. In the hygiene sector, the move from tissue only cores to pulp and SAP cores increased air volumes significantly—in many cases by a factor of 15-20 times. As all air exiting the building had to be replaced, incoming air also had to increase by the same amount. A hygiene production system requiring say 50×10³ m³/hr requires an air replacement back into the factory of 50×10³ m³/hr, a total factory requiring say 500×10³ m³/hr requires an air replacement back into the factory of 500×10³ m³/hr. As such, HVAC systems had to be increased to meet demand and the power requirements for the HVAC systems also increased.

As power consumption of HVAC systems sky-rocketed, enhancements in efficiency were urgently needed and as such many new systems evolved where the air filtration performance installed that cleaned the air to a very high specification thereby allowing the return of air back into the factory whilst not jeopardizing the health of factory workers. In FIG. 1C, in addition to the elements of the previous figures, a factory configuration is depicted with air filters (135) specified to clean the air to HEPA standards and as such, the air exiting the air filters can be sent back into the factory production area.

This new technology made great inroads into reducing HVAC tonnage and the respective power requirements to operate the HVAC systems. As the installation numbers of such technology slowly increased around the world, it was clearly evident that the benefits of the technology varied significantly from industry to industry and from process to process and from location to location. In scenarios where air exiting the filter had an elevated air temperature, the incoming air would significantly heat the manufacturing room of the factory. In some locations, say in northern or southern hemisphere locations during the winter period, this heat was put to use and used as free heating. As such, to achieve this, additional valve systems (140) were installed as shown in FIG. 1D, showing the same elements as the previous figures except for additional valve configuration (140), which can be operated either manually or automatically to divert the air exiting the air filters to be either sent back into the factory or to the exterior of the factory or a mixture between. These valve systems are typically adjusted to achieve either full venting of filter air outside (say in hot climates where exhaust air is hot) or the full venting of the filter air inside the factory (say in cooler climates where exhaust air is hot). In many instances such valves are controlled by computer systems that constantly measure outside environments, air temperatures, power costs and adjust the values accordingly to ensure the most efficient settings are achieved.

Whilst a set-up as shown in FIG. 1D made huge inroads into efficiency, the set-up is still not ideal. Having invested capital spending into the air filtration equipment to achieve the high air standards required to refeed the air, it is a great loss in performance that this capability cannot be used 24/7 in all locations. This loss also implies secondary losses, in that, HVAC capacity still needs to be installed at great capital cost to ensure good operation during the periods when air recycling cannot be achieved and all incoming air can be adequately treated prior to entry back into the factory, and, during this period, significant power is required to run the HVAC.

Connecting a heat exchange to the outlet of the filtered air that allows external factory air to enter the heat exchanger and exit back outside the factory without coming into contact with the filtered air solved this issue and allows air recycling on a 24/7 basis. FIG. 1E outlines the addition of a heat exchanger (145) to the filter system as depicted FIG. 1C. The additional heat exchanger cools the air exiting the air filter prior to this air entering the factory production area In this scenario, production air is taken from the production process via fans and passed into the filter to remove all contaminants, thereafter exiting the filter process and entering the heat exchanger where typically at this stage, the air would be at 65° C. As the air passes through the heat exchanger, the air is cooled by the external ambient air and passed back into the factory production area. Preferably, the two-way heat exchanger has dedicated air zones that are not connected with each other and the air streams do not mix and as such, the absolute moisture levels, i.e. water contents of the air, are not changed. Due to the complete separation of the air streams, adiabatic cooling processes can be installed in the external factory air entering the heat exchanger that gives additional cooling power without changing humidity of the factory air.

As outlined above, the mind-set within industry to date has been to recirculate the filtered air back into the factory production area when this has made economic sense. However, options do exist with some production processes to send this air directly back to the production process and operate a close loop system. This closed loop system has three key benefits in that (1) it fully separates all interactions with process air and factory room HVAC air, (2) it allows the process air to operate at a different temperature to the factory room air, (3) it allows the process air to operate at a different moisture level to the factory air. FIG. 1F depicts this scenario where the ducts are shown that feed the air back into the process. FIG. 1F depicts the same elements as shown in FIG. 1E, however, in this factory configuration the outlet of the heat exchanger, that cools the air exiting the air filter, is sent back to the production system (150) where this air is circulating and a closed-loop or semi closed loop where the ducting diverting this air back to the production system.

A method to enhance this process is to capture air-conditioned air that would normally exit the building and use this cooler dryer air to boost the performance of both the heat exchanger and the adiabatic cooling process. A well designed HVAC system typically exchanges respectively replaces the air about 10 times per hour, and this air which is continuously being re-circulated has new fresh conditioned air from outside injected into this air stream at values of around ten percent. As this newly injected air enters the process and factory, air within the factory is typically vented to the environment and the energy invested to de-humidity this air is lost. By reducing the percentage of air exiting the factory and diverting this air back into the adiabatic cooling processes thereby reducing the wet-bulb temperature further. This concept is shown in FIG. 1G where the factory air enters the heat exchanger to aid in this process. The system depicted in FIG. 1G has the same elements as the system shown in FIG. 1F, however, the heat exchanger used in this factory configuration is more than a basic two-way heat exchanger and the heat exchanger has additional inlets to allow the processing of factory air where the ducting diverting this air from the factory production area into the heat exchanger.

By utilizing the wasted air and also by adding efficient moisture control devices, standard HVAC systems are no longer required. This concept is shown in FIG. 1H where the factory operates with no standard HVAC systems at all. FIG. 1H depicts the same embodiments as shown in FIG. 1G, however, the factory air, and or process air treatment system (160) has dedicated air humidity control and as such, the standard HVAC systems as outlined in FIGS. 1A to G is no longer required.

FIG. 2 A to D depict schematically and exemplarily various air management systems according to the present invention. As shown in FIG. 2A, such a system (200) can be used in a manufacturing set-up or a production factory (210) with a production area (215), which is separated from the external ambient environment (205) by a wall (217) and in which at least one, but typically more, sometimes even up to 50 or more production system(s) (230) or lines is/are placed. A production system (230) comprises at least one, typically more, often more than 20 production steps on particular production step equipment (245).

Such production step equipment may be—without any limitation—hot melt application systems, ultrasonic system, separation or cutting systems, defiberization systems, separation systems, web handling drive system, web handling friction systems, etc. During the operation of such production step equipment (245) the air properties of the process air in the direct vicinity of this equipment are often impacted (250) such as by an increase in temperature, dust level, or change in relative or absolute humidity, thusly also the aerial environment of the production system, i.e. the process air (240) exhibits a change in properties. In order to separate this process air from the areal environment (220) of the production room or area (210), the production equipment may be separated by a housing (235) from the production area (210). Such a housing may preferably also function as a sound retarding element, or also as a safety element for the health or safety of an operator (236). The air management system further comprises an air treatment system (260). Duct work (270) may transfer air from the process (240) and/or the production room (220) to the air treatment system (260) and back to the production system or the production area. The air treatment system may comprise filter elements (not shown) but very preferably comprises a heat exchange system for exchanging energy between the process and optionally production room air and external ambient air as entering the air treatment system at an air entry (262) and leaving it at air exit (268).

In FIG. 2B further options for the air management system are schematically, shown, such as a fan element (280), or further temperature adjustment elements (282) (like cooling elements preferably cooling water at ambient temperature, heating elements, energy exchange elements between other elements connected via said duct system, or heat pumps, preferably by exploiting geothermal energy), dust reduction elements (284), e.g. filter elements, air humidity adjustment elements (286), or flow adjustment elements, in particular valve elements (288). Further, as indicated in FIG. 2C, air flow may be dedicated towards particular and predetermined process step elements, e.g. by an air flow splitter (272), optionally followed by one or more of such treatment in such elements (generally indicated by 285).

In FIG. 3D a further option is depicted, namely that the factory room air is extracted separately from the process air, and treated in the heat exchanger in a separate heat exchange system, e.g. as the one depicted in FIG. 4F. In FIG. 3 A to C more exemplary details of a filtration and heat exchanger system (300) to execute the respective processes are depicted. As shown in FIG. 3A, incoming air (305) is delivered via ductwork to the air filter with the air filtration system (310), where air passes between interfaces (not shown in this layout) into the heat exchanger (315). The indicated factory roof (320), through which external air under ambient conditions is entering the heat exchanger at the air entry (325). Optionally, an adiabatic cooling process can be attached, optionally with additional air inlets (330) where internal factory room air can be added and where also an adiabatic cooling process can be attached. Then, air passing through the heat exchanger (315) exits the heat exchanger and factory to the exterior environment via air exit (335). The original process air from the convertor can be refed from the heat exchanger back into the factory room production area (340).

In FIG. 3B, a further more detailed view of the filtration and heat exchanger system of FIG. 3A is shown, with air filter (375), through which air (345) passes, optionally via fans (not shown) into the heat exchanger. Also indicated are internal plates (350) of the heat exchangers, and low pressure suction fans (355) adapted to pull air through the heat exchanger. The external cooling air inlet (360) from the external ambient environment of the factory may provide air that is non treated air or that is cooled, preferably via adiabatic cooling process or similar, optionally driven by low pressure suction fans (365) that pull air through the heat exchangers. From the air exit (370) the air exiting back out of the factory to the ambient environment.

FIG. 4A to D depict even further details of the heat exchanger systems of FIG. 3. FIG. 4A shows an end view with plates (405) within the heat exchanger that conduct heat and prevent the air streams from mixing and with a low pressure suction fans (410) that pulls air through the heat exchanger. FIG. 4B shows a perspective view, with the air (415) traveling from the filter, optionally via fans, into the heat exchanger with its internal plates (420). Low pressure suction fans (425) are adapted to pull air through the heat exchanger. In FIG. 4C, the internal block (430) consisting of multiple internal plates of the heat exchanger is depicted, and in FIG. 4D preferred details of this heat exchanger system of FIG. 4C are shown, with cooling air (440) entering the heat exchanger, and the hot air entering the heat exchanger to be cooled (not shown), separated by the plates (420) within the heat exchanger that conduct heat and prevent the air streams from mixing.

FIG. 3C outlines a more detailed view of another execution of the filtration and heat exchanger system similar to the one of FIGS. 3 A and 3B. Therein, air coming into the air filter (305) via ductwork to the air filtration system (310), where air passes between interfaces (not shown in this layout) into the heat exchanger (315). External air is entering the heat exchanger through an air inlet (325) through the factory roof (320) optionally followed by an adiabatic cooling process. Optionally, internal factory air can be added via additional air inlets (330), optionally also followed by an adiabatic cooling process. After passing through the heat exchanger (315) the air exits the heat exchanger and factory to the exterior ambient environment through an air exit (335). Thus, the original process air from the convertor exits the heat exchanger and is refed back into the original production process (340) whilst air (380) is sucked from the factory air into the heat exchanger where it is heated or cooled and this same air stream (385) entering back into the factory at changed air properties.

FIG. 4E to G outlines a more detailed sectional view of the heat exchanger systems shown in FIG. 4A to D. In FIG. 4E, a two-way heat exchanger system is depicted, with the entry point (442) of the external ambient air, which passes through the heat exchanger to then leave it at the exit point (448), with this air flow stream not coming into contact with the horizontal air flow stream passing through the heat exchanger though the void spaces of the heat exchanger (440). FIG. 4E shows a four-way heat exchanger system with a first (452′) and a second (452″) entry point of the external ambient air which passes through the heat exchanger and out again at first and second exit points (458′ and 458″, respectively) with these air flow streams not coming into contact with each other nor with the horizontal air flow stream passing through the heat exchanger though the void spaces of the heat exchanger (450′ and 450″, respectively). There may be even more option of multi-way heat exchangers, e.g. a six-way heat exchanger system with a first (462′), a second (462″) and a third (462′″) entry point of the external ambient air, which passes through the heat exchanger and out again at first (468′), second (468″) and third (468′″) exit points, respectively. with these air flow streams not coming into contact with each other nor with the horizontal air flow stream passing through the heat exchanger though the void spaces (460′, 460″, and 460′″, respectively).

FIG. 5 A to D depicts further particular executions for a diaper convertor platform (500). In FIG. 5A, a production system respectively it's machine body (505) is shown, for which process air (510) is being extracted from the production system via a duct system towards the filter/HVAC system (with the arrow on the duct depicting flow direction), and where treated air (520) is being returned back to the process areas of the production machine (with the arrow on the duct depicting flow direction). In FIG. 5B, a similar system is shown, for which the return air (520) duct has been enlarged to reduce pressure drop and overall resistance (with the arrow on the duct depicting flow). Further, in the system depicted in FIG. 5C, the return air is no longer sent back via dedicated duct but is returned back to the production process via a void space (530) inside the machine body (505). Similarly, as indicated in FIG. 5D, a duct (510) may be used to extract process air from the diaper process (with the arrow on the duct depicting flow direction), and re-fed as return air via the void space (530) in the diaper machine framework (505).

Claims

1. A manufacturing set up (210) for the manufacturing of hygiene products comprising: wherein said air property management system comprises:

an air property management system (200) said hygiene products being selected from the group consisting of baby and adult incontinence absorbent articles, feminine hygiene articles, and materials adapted to be used in such articles, selected from the group consisting of nonwoven, films, and composites thereof said manufacturing set up (210) comprising:

a) a production area (215) comprising: walls (217) adapted to separate the production area (215) from an external ambient environment (205); a manufacturing room comprising space for at least one manufacturing equipment (230) of said baby and adult incontinence absorbent articles, feminine hygiene articles, and materials adapted to be used in such articles, a multiplicity of said manufacturing equipment, and for operators (236), said manufacturing room further comprising an aerial environment (220);

b) said at least one manufacturing equipment (230) of said articles in said manufacturing room, said at least one manufacturing equipment comprising: a manufacturing equipment housing (235) separating process air of a manufacturing equipment aerial environment (240) from room air of said aerial environment (220), said manufacturing equipment housing being integral with a sound retarding housing; said baby and adult incontinence absorbent articles, feminine hygiene articles, and materials adapted to be used in such articles forming elements (245) inside said housing adapted to change at least one process air properties (250), said properties being selected from the group consisting of temperature, moisture content, dust content, and pressure; and said baby and adult incontinence absorbent articles, feminine hygiene articles, and materials adapted to be used in such articles forming said elements (245) being selected from the group consisting of hot melt application systems, ultrasonic systems, separation systems, defiberization systems, separation systems, web handling drive system, and web handling friction systems;

c) an air treatment system (260), wherein said air treatment system is a HVAC system; and

d) a duct work (270) adapted to connect said manufacturing equipment housing (235) to said air treatment system (260) in a closed loop system;

an indirect heat exchange system as said air treatment system (260) and adapted to transfer energy from said external ambient environment (205) to said aerial environment (220) or said process air of said manufacturing equipment aerial environment (240) without mixing of the energy transferring air streams, wherein said indirect heat exchange system is an adiabatic heat exchange system.

2. The manufacturing setup of claim 1, wherein the air management system further comprises one more elements selected from the group consisting of one or more temperature adjustment element(s) (282) comprising indirect heat exchange elements, selected from the group consisting of cooling elements cooling water at ambient temperature, heating elements, energy exchange elements between other elements connected via said duct system, and heat pumps;

closing valves (288) in said duct work, said duct work adapted to be closed, manually or automatically, in case of an opening of said housing;

a fan element (280);

an air humidity adjustment element (286) adapted to allow increase or decrease of the absolute humidity (water content) of the air;

a dust reduction system (284), filter, wherein said dust reduction system is a HEPA filter; and

an automated control system for adjusting process settings according to production processing variables as well as external ambient air conditions.

3. The manufacturing setup of claim 1, wherein the air management system further comprises:

an air flow distribution system comprising valves (288), and side ducts, wherein further air treatment systems are adapted to provide predetermined air flows to various parts of the system and to different article forming elements.

4. The manufacturing setup of claim 1, wherein said indirect heat exchange system of said air property management system is a multi-way heat exchanger, comprising multiple layers consisting of a 3D surface structure of materials separating airflows within the heat exchanger, and of a high-surface area honeycomb type.

5. The manufacturing setup of claim 1, wherein said indirect heat exchange system of said air property management system is adapted to match dimensions of a standard ISO 668 container, whereby the housing provides structural integrity to achieve ISO 668 standards and to support material layers of said indirect heat exchange system.

6. A process for management of air properties in manufacturing of products in a manufacturing set up, said products selected from the group consisting of baby and adult incontinence absorbent articles, feminine hygiene articles, and materials adapted to be used in such articles, selected from the group consisting of nonwoven, films, and composites thereof, said process for management of air properties comprising the steps of:

providing a manufacturing set up (210) comprising: a) a manufacturing room (215) comprising: walls (217) adapted to separate the manufacturing room from an external ambient environment (205), said manufacturing room comprising space for manufacturing equipment (230) of said articles, a multiplicity of manufacturing lines and for operators (236) said manufacturing room further comprising an aerial manufacturing environment (220); b) said manufacturing equipment (230) of said articles in said manufacturing room, said manufacturing equipment comprising: a manufacturing equipment housing (235) separating process air of manufacturing equipment aerial environment (240) from room air of said aerial manufacturing environment (220), said housing being integral with sound retarding housing; a plurality of article forming elements (245) inside said housing adapted to change at least one air properties (250) in said manufacturing equipment aerial environment, said properties being selected from the group consisting of temperature, moisture content, dust content, and pressure; and said plurality of article forming elements (245) being selected from the group consisting of hot melt application systems, ultrasonic systems, separation systems, defiberization systems, separation systems, web handling drive system, and web handling friction systems; c) an indirect heat exchange system (260); and d) duct work (270) adapted to connect said manufacturing equipment housing (235) to an indirect heat exchange system (260) in a closed loop system; changing the properties of said manufacturing equipment aerial environment (240) by operating said plurality of article forming elements; transferring said process air from said manufacturing equipment aerial environment (240) to said indirect heat exchange system; treating the process air from said manufacturing equipment aerial environment (240) and said room air of said aerial manufacturing environment (220), if present, by exchanging energy with ambient air in an indirect heat transfer that is an adiabatic heat transfer, wherein the content of the ambient air in an air stream leaving said indirect heat exchange system is selected from the group consisting of less than 50%, less than 80%, less than 10%, less than 1% and essentially zero; whereby the indirect heat transfer between said ambient air and said processing air is an adiabatic heat exchange.

7. The process for management of air properties of claim 6, further comprising the step of submitting the process air and room air, if present, to one or more steps selected from the group consisting of further heating or cooling, adjusting water content by adding or removing moisture, reducing dust level, creating a further pressure differential, interrupting said air flow of said processing and said treated air by stop valves upon opening said walls of said manufacturing equipment, collecting air from more than one of said manufacturing equipment, directing more than one air flow to said indirect heat exchange system, by operating a multi-way heat exchanger, and diverting said air flow of treated air towards two or more endpoints.