Method and device for delivering fluid, and a heat transfer cartridge
A method and device for delivering a fluid, in which the fluid is fed from a fluid source of a fluid-delivery device and delivered through a discharge orifice assigned to the delivery device. Before the fluid is delivered through the discharge orifice, it is heated or cooled by flowing through a heat-transfer chamber, which contains a fluid-permeable structure having a large number of communicating cavities through which the fluid flows.
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The invention generally concerns a method and device for delivering a fluid such as a gas or a liquid.
BACKGROUND OF THE INVENTIONIn many industrial applications, fluid materials (fluids) are delivered with the aid of fluid-delivery devices and deposited on or applied to substrates. The fluid materials may be, for example, adhesives, paints, or sealing materials, and the substrates may be personal care products, plastic sheets, furniture, machine parts, or the like. Depending on the application, the fluid materials may be delivered, for example, in the form of beads, strips, or films, or the material may possibly be sprayed with the aid of a gas jet that affects the fluid. The fluid-delivery devices are connected to a fluid source, for example, an adhesive reservoir, and the fluid is fed by a pump through so-called application valves to a discharge orifice, which is, for example, circular or slot-shaped.
In some applications, it is advantageous to heat the fluid before it is delivered. In spray processes, it may be advantageous to heat a gas that acts on the fluid to be delivered. For this purpose, it is well known that the base of the delivery device can be electrically heated, so that liquid or gas flowing through flow channels formed in the base is heated by convective heat transfer at the inner wall bounding the flow channel. To heat a gas in a fluid-delivery device, it is well known to use a gas flow channel that follows a zig-zag pattern. The purpose of the zig-zag design is to lengthen the flow path available for heat transfer and in this way improve the heat transfer. However, this has the disadvantage that the designs needed to produce this type of flow path are very involved and thus expensive.
The goal of the present invention is to develop a method and device of the type described above and a cartridge to improve heat transfer.
SUMMARY OF THE INVENTIONThe invention achieves the goal with respect to a method of the type described above in such a way that, before it is delivered through the discharge orifice, the fluid is heated or cooled by flowing through a heat-transfer chamber. The heat-transfer chamber contains a fluid-permeable structure or foraminous body with a large number of communicating cavities or interconnected interstices, such that the fluid circulates through this structure.
Furthermore, the invention achieves the goal with respect to a device of the type described above by a heat-transfer chamber for heating or cooling the fluid, which contains a fluid-permeable structure with a large number of communicating cavities.
The advantages of the invention include significantly improving the heat transfer for heating or, alternatively, cooling a liquid and/or a gas before it is delivered by the delivery device. More specifically, this advantage is achieved by the fluid-permeable structure of the invention through which the fluid circulates. The fluid-permeable structure is preferably a sintered material, especially a sintered metal, which is essentially rigid and has a large number of intercommunicating cavities through which the fluid can circulate. Due to the fluid-permeable structure present in the flow channel of the heat-transfer chamber, the heat transfer is improved by virtue of the fact that the surface area between the structure and the fluid to be heated or possibly cooled, which is crucial to the transfer of heat, is greatly increased and multiplied. The structure is heated and the heat can be transferred to the fluid over the large surface area of the structure. Furthermore, the heat transfer is improved by the fact that the fluid is repeatedly deflected as it flows through the structure. This produces a certain amount of turbulence which, in turn, results in improved heat transfer.
In accordance with the invention, the heat transfer involved with, for example, the heating of a liquid or a gas, is thus significantly improved and, as a result, the device can be built relatively compactly. Especially in the case of the heating of compressed gas for delivery devices for spraying liquids, such as hot-melt adhesives, the increased flow resistance produced by the fluid-permeable structure, compared to a free-flow channel, is negligible. The use of sintered metal as the preferred material has the advantages that it has a large internal heat-transfer surface, is dimensionally stable, is easily produced and processed, and thus can be adapted to specific applications. Alternatively, however, it is also possible, in accordance with the invention, to use other open-pored, preferably essentially rigid, structures, such as fabrics, metal braids, or rigid, open-pored cellular plastics.
Advantageously, as the fluid flows through the heat-transfer chamber, it can be heated or cooled and simultaneously filtered by the fluid-permeable structure, so that, in addition to being heated, a gas or liquid is also purified.
To introduce heat into or remove heat from the fluid, the fluid-permeable structure is preferably in contact with the inner surface of the heat-transfer chamber. In this way, efficient heat transfer occurs.
It is especially preferred for the fluid to be a liquid, especially a fluid plastic, such as a hot-melt adhesive, and for it to be heated by flowing through the heat-transfer chamber. It is likewise preferred for the fluid to be a gas, preferably air, and for it to be heated by flowing through the heat-transfer chamber, which is advantageous in spray applications.
The device of the invention is refined by a simple design modification by forming the heat-transfer chamber as a section of the flow channel, into which the fluid-permeable structure is inserted. In this way, the heat-transfer can be improved in a flow channel formed in a housing or base of the delivery device in a simple way by inserting a fluid-permeable structure of the invention.
It is especially preferred for the fluid-permeable structure to be designed essentially as a cylindrical body, which is inserted in an essentially cylindrical bore. This allows simple production and installation as well as replacement of the fluid-permeable structure.
A further advantage is realized if the fluid-permeable structure is a mechanically finished sintered metal part, preferably a turned sintered metal part. The heat transfer between the sintered metal part and the heat-transfer chamber is further improved by mechanical finishing, e.g., turning, of a surface of the sintered metal part that is in contact with the heat-transfer chamber. As a result of the turning, the outer pores are partially sealed, and a larger contact surface is produced, without adversely affecting the inner structure, through which the fluid flows.
Advantageously, the heat-transfer chamber is formed in a metal housing, and the housing contains heating elements for heating the housing.
It is especially preferred for the fluid-permeable structure to be designed as part of a cartridge that can be inserted in the device. The cartridge is detachably mounted in the device, and the fluid flows through it. This allows fast and easy replacement of the cartridge. It is advantageous for the cartridge to have at least one heating element.
In accordance with an alternative embodiment, it is proposed that the device have a base, in which the one or more heat-transfer chambers are installed, and that one or more application modules are provided, which are installed on the base and contain the discharge orifice for delivering the fluid. If needed, several heat-transfer chambers can be connected in series or in parallel. They are preferably installed in separate housing sections, which can be attached to one another.
Additional advantageous modifications will become apparent upon further review of the specification.
BRIEF DESCRIPTION OF THE DRAWINGSThe invention is described below on the basis of preferred embodiments illustrated in the attached drawings.
The device shown in
A hose connection socket 18 serves to connect the device 1 with a fluid source, such as an adhesive reservoir for liquid adhesive (not shown). The adhesive is conveyed through a flow channel which is composed of several sections and runs through the base 2 and into the application modules 4, 6, 8, 10 as far as the discharge orifices 12. The adhesive flow channel has a first bore 20, which is shown only schematically by the broken line, a transverse distribution channel 22, oblique bores 24, which communicate with the transverse distribution channel 22 and lead to each of the modules 4, 6, 8, 10, and additional channels, which are formed inside the application modules 4, 6, 8, 10 and open into the discharge orifice 12.
To allow selective starting or stopping of the flow of the adhesive inside the device 1, each module 4, 6, 8, 10 contains a valve system (not shown in detail), which has a valve body that can be moved pneumatically from an open to a closed position and interacts with a valve seat. The valve system is operated by an electrically controllable solenoid valve 26, control air lines 28 connected to the solenoid valve, and compressed gas channels formed in the base 2, which are only indicated by the broken lines 30, 32 and serve to introduce compressed gas into the application modules 4, 6, 8, 10.
An air connection socket 34 is installed on the base 2 to supply gas, e.g., in the present embodiment, compressed gas. The compressed gas flows through several compressed gas channels, which are described in greater detail below and are used for spraying or swirling the fluid delivered through the discharge orifice 12.
For heating the spraying gas, preferably air, several heat-transfer chambers 36, 38, 40, 42, 44, 46 are formed inside the base 2. The gas flows through the heat-transfer chambers in the direction indicated by the arrows. In the present embodiment, there are two series-connected preheating heat-transfer chambers 36, 38 and four additional, parallel-connected heat-transfer chambers 40, 42, 44, 46, each of which is assigned to an application module 4, 6, 8, 10. Alternatively, however, depending on the specific application, there may be different numbers of series-connected or parallel-connected heat-transfer chambers or even only a single heat-transfer chamber. The heat-transfer chambers 36, 38, 40, 42, 44, 46 are arranged parallel to one another in a plane in the upper section of the base. As
A fluid-permeable structure that contains a large number of communicating cavities is provided in each heat-transfer chamber. In the embodiment shown here, the structure is formed by cylindrical sintered metal parts 48. The heat-transfer chambers with the fluid-permeable structures arranged within them serve primarily to improve the heat transfer, i.e., in the present embodiment, to improve the heating, of the gas flowing through the fluid-permeable structure. The sintered metal parts are essentially rigid and may consist, for example, of a bronze-copper alloy. Alternatively, however, the fluid-permeable structure may also consist of metal fabric, metal braid, or an open-pored, rigid cellular plastic material, through which gas or liquid can flow.
The sintered metal parts 48 are cylindrical and are fitted to and inserted in cylindrical bores 50 formed in the base 2. The addition or removal of heat is explained in detail below. Each bore 50 is formed as a through-hole in the base or, more precisely, its housing sections. The sintered metal parts 48 can be inserted from the inlet ends 52, which are readily distinguishable in
To supply heat to the heat-transfer chambers 36-46 and the fluid-permeable structures (sintered metal parts 48), electric resistance heaters are installed inside the base 2, namely, inside several heater bores 58, 60, as
The alternative embodiment of a cartridge 71 of the invention that is shown in
The alternative cartridge shown in
In the example shown in
As illustrated in
Claims
1-33. Canceled.
34. A method of transferring heat to or from a fluid flowing through a foraminous body positioned in a fluid chamber, comprising:
- feeding the fluid into the fluid chamber,
- heating or cooling the foraminous body positioned in the fluid chamber,
- feeding the fluid through interstices of the foraminous body,
- transferring heat between the fluid and the foraminous body, and
- delivering the fluid from the foraminous body to a fluid-delivery device.
35. The method of claim 34, wherein feeding the fluid through the interstices of the foraminous body further comprises feeding the fluid through the interstices of a sintered metal, a woven material, a metal fabric, or a cellular plastic.
36. The method of claim 34, further comprising:
- filtering the fluid as the fluid is fed through the interstices of the foraminous body.
37. The method of claim 34, wherein the fluid is a liquid hot-melt adhesive.
38. A device for delivering a fluid, comprising:
- a dispensing body having a flow channel capable of being connected with a source of the fluid, and a discharge orifice communicating with said flow channel for delivering the fluid,
- a heat-transfer chamber communicating with said flow channel,
- a foraminous body positioned in said heat-transfer chamber and having interconnected interstices capable of receiving the fluid from said flow channel and delivering the fluid to said discharge orifice, and
- a heat transfer device thermally coupled with said foraminous body and capable of transferring heat with respect thereto for heating or cooling the fluid flowing through the interconnected interstices.
39. A device in accordance with claim 38, wherein said foraminous body is constructed from a material selected from a group consisting of: a sintered material, a woven material, a metal braid, and an open-pored cellular plastic.
40. A device in accordance with claim 38, wherein said heat-transfer chamber is formed by a section of said flow channel into which said foraminous body is inserted.
41. A device in accordance with claim 38, further comprising:
- a housing containing said heat-transfer chamber, said housing further containing heating elements for heating the foraminous body.
42. A device in accordance with claim 38, further comprising:
- a cartridge carrying said foraminous body, said cartridge being insertable into and removable from said heat-transfer chamber.
43. A device in accordance with claim 42, further comprising:
- at least one heating element carried by said cartridge.
44. A device in accordance with claim 43, wherein said foraminous body surrounds said heating element.
45. A device in accordance with claim 43, wherein said heating element surrounds said foraminous body.
46. A device in accordance with claim 38, further comprising:
- at least one application valve module communicating with said heat-transfer chamber and having said discharge orifice for delivering the fluid.
47. A cartridge for transferring heat to or from a fluid, comprising:
- a foraminous body having interconnected interstices through which the fluid may flow, and
- a heat transfer device thermally coupled with said foraminous body and capable of transferring heat with respect thereto for heating or cooling the fluid flowing through the interconnected interstices.
48. A cartridge in accordance with claim 47, further comprising:
- a housing having a hollow interior space, said foraminous body positioned within said hollow interior space.
49. A device in accordance with claim 47, wherein said foraminous body is constructed from a material selected from a group consisting of: a sintered material, a woven material, a metal braid, and an open-pored cellular plastic.
50. A device in accordance with claim 47, wherein said foraminous body surrounds said heating element.
51. A device in accordance with claim 47, wherein said heating element surrounds said foraminous body.
Type: Application
Filed: Nov 13, 2003
Publication Date: Mar 10, 2005
Applicant:
Inventor: Eric Lingier (Straelen)
Application Number: 10/712,521