Abstract: An oil pressure control apparatus which includes a source of hydraulic pressure introducing the hydraulic pressure to a hydraulic actuator which is actuated by hydraulic pressure, a fluid passage which is connected between the source of hydraulic pressure and the hydraulic actuator for introducing and discharging hydraulic pressure from the source of hydraulic pressure to the actuator, a control valve which is disposed in the fluid passages for controlling the hydraulic pressure and a filter is disposed in a position that is between the actuator and the control valve. Thereby, the control valve is capable to be operated smoothly.

Abstract: A fuel-conditioning device for removing moisture from fuel includes two replaceable fuel-conditioning cartridges. The cartridges are alternately put in use by selectively positioning a valve actuator. A marking system for the fuel-conditioning cartridges and the valve actuator identifies which cartridge is in use and which can be serviced. A cartridge can be replaced while maintaining a continuous flow of fuel.

Abstract: A replaceable cartridge type dual stage bypass valve is used in dual filter multi-media filtration assemblies. The cartridge may be selected and easily replaced to meet the various combinations and requirements of the dual filter elements (primary and secondary). The individual bypass valves that form the dual stage bypass valve may each be responsive to a predetermined increase of pressure due to a clogged filter condition. The individual bypass valves may use replaceable coil springs. The spring force of the coil spring is determined by the pressure differential to be resisted, i.e., the resistance to be offered by the spring action of the spring, and the flow capacity at a given pressure differential.

Abstract: A redundant array pumping system and control system is provided for water rides for ensuring continuous and non-disruptive supply of water. The pumping system incorporates a redundant pump and filter array in conjunction with a nozzle system for injecting water onto a ride surface. The nozzle system may incorporate a plurality of redundant or quasi-redundant nozzles. The hydraulic system can include many levels of redundancy as applied to its various components, such as pumps, filters and nozzles. Additionally, the system can be equipped with a plurality of pressure and flow sensors for monitoring and controlling the performance of the pumps, filters and nozzles of the hydraulic system.

Abstract: In order to provide a simply-structured fuel filter which permits soaking at least part of a filter unit all the time in fuel in a reservoir, a reservoir unit is configured of a resin-built cylindrical reservoir having a bottom arranged on the bottom of a fuel tank, a primary filter installed near the inner bottom of that reservoir and a fuel pump sucking fuel in the reservoir through the primary filter, wherein projections protruding upward from the inner bottom of the reservoir are integrally molded and engaging holes to engage with those projections are bored in the circumference of the primary filter.

Abstract: A switching device for optionally passing a flow of medium, such as a highly pressurized gas, through a first or second treatment member (2, 3), in which the medium is subjected to a treatment, such as filtration, heating, cooling or the like, comprises a medium inlet, a medium outlet and two distribution valves (1, 5), of which the valve bodies, which are provided with passages, are attached to a common rotation pin (10). For safety's sake, safety valves (12, 13, 14, 15) are arranged in the connections between distribution valves arranged at the inlet and at the oulet and the two treatment members.

Abstract: A hydraulic control valve has a valve block provided with a plurality of ports, a valve body formed with ports corresponding to the ports of the valve block, and a plate disposed between the valve block and the valve body. The plate has a flow passage for providing communication between the ports of the valve block and the ports of the valve body. A filter is disposed in the flow passage.

Abstract: A multi-part filter combination is received in a stepped bore of a fluid-carrying component. A larger-diameter filter part is associated with a larger-diameter bore portion, and a smaller-diameter filter part is associated with a smaller-diameter bore portion. The two filter parts of the filter combination are connected by a connecting part. When the two filter parts are joined in their respective final position in the bore, this connecting part is detachable by means of a die to be introduced into the bore. The filter combination can be used in a valve block serving to receive a magnet valve.

Abstract: Engine oil solenoid control valve having a solenoid coil, a solenoid armature movable by energization of a solenoid coil, a check valve communicated to a fluid exhaust port of the control valve, a fluid control valve movable relative to a fluid control port in response to armature movement, and a permanent magnet disposed relative to one or more fluid supply ports of the control valve to magnetically attract and hold or getter ferrous particles in hydraulic fluid supplied to the supply port(s).

Abstract: A socket (A) includes a first flow passage (4) which is provided with a first closure member (14) and a first check member (32). And a plug (B) includes a second flow passage (54) which is provided with a second closure ember (64) and a second check member (82). The second check member (82) comprises a larger-diameter member (86) and a smaller-diameter member (88). A first cylindrical filter (20) is arranged on an outer periphery of the first closure member (14). A second cylindrical filter (37) is arranged on an outer periphery of the first check member (32). A third cylindrical filter (70) is arranged on an outer periphery of the second closure member (64). Each of the cylindrical filters (20), (37) and (70) comprises an inner perforated sheet (41), a screen (42) and an outer perforated sheet (43) arranged in the mentioned order from an interior area.

Abstract: A pressure operated normally closed control valve operates to open at a predetermined pressure between the system minimum and maximum pressures to open the valve and allow the discharge of condensate from the system which has a source of pressure to provide a minimum and a maximum pressure. The system is subject to the formation of condensate. There is an inline filter at the inlet end of the valve and a discharge nozzle at the outlet end of the valve. The entrance to the discharge nozzle may also have a filter. The assembly can also be arranged so that the control valve is normally open and operates to open at a predetermined pressure at or below the system minimum pressure whereby condensate is removed, and to close the valve and prevent the discharge of condensate from the system when the pressure falls below the predetermined pressure.

Abstract: A back flow prevention valve for preventing water from draining back into a water supply line. The back flow prevention valve includes a housing comprising a tubular body having a first and second open end each having a respective covering thereon with an aperture extending therethrough. A water supply pipe is fluidly coupled to the aperture in a first covering. A cylinder is coupled to the first covering and extends inward of the tubular body. A piston having a bore extending therethrough is slidably positioned in the cylinder. A biasing member biases the piston toward the first covering. The aperture in the second covering has a ledge therein for opening the valve. A one-way valve is removably coupled to the piston and is adapted for letting water move outwardly through the piston toward the second end of the tubular member.

Abstract: A filtration cartridge faucet assembly contains a filtration body that is concealed beneath a sink deck through the use of an escutcheon mount. The escutcheon mount permits access to a renewable filtration core from above the sink deck while concealing and protecting the filtration body.

Abstract: A device for an arrangement inside a fuel tank, provided with pumps and filters for supplying and filtering fuel that is fed to an internal combustion engine, whereby the fuel is conveyed from the bottom area of the tank through a first filter into a collector chamber and fuel is conveyed from said collector chamber by means of a second pump through a second filter to the internal combustion chamber. Both pumps are arranged in a pump unit. The collector chamber is arranged vertically above the pump unit and the filter with respect to the fitting position of the device and is embodied as an open overflow container, whereby the inventive device can be produced in a rational manner and offers good functionality.

Abstract: A filter system especially useful in the treatment of waste material, in particular liquid waste material which may include particulate matter therein. The filter system includes a series of filters of progressively finer porosity in order to selectively eliminate particulate (or semi-particulate) matters from a carrier material, typically but not exclusively, of a fluid or liquid nature. The filters are mounted within a housing which includes an outlet port and a plurality of inlet ports, wherein each inlet port includes a check valve.

Abstract: The filter element assembly includes a three-way valve member internal to the assembly. The filter element comprises a primary filter construction defining an open internal volume, a first end cover, a second end cover, and a valve construction. The valve construction is positioned within the primary filter construction open internal volume and includes a valve member movable between first, second, and third valve positions. The first valve position blocks fluid flow through a bypass, such that fluid only flows through the primary filter construction. The second valve position permits fluid flow through a secondary filter construction. The third valve position permits fluid to bypass both the primary and secondary filter constructions, and proceed directly to the open internal volume and into an outlet. Methods for filtering are provided.

Abstract: A filter system (50) includes first and second filter heads each including a housing receptacle and a filter receptacle. The second filter head (10) includes an inlet (42) providing fluid communication to the housing receptacle; an unfiltered-fluid outlet (44) connected to the inlet of the first filter head (9) via an unfiltered-fluid line (64); and a filtered-fluid outlet (46) providing fluid communication to the filter receptacle and connected to the filtered-fluid opening (32) of the first head via a filter-fluid line (62). A filtered-fluid outlet (47) is provided in the first head for filtered fluid to leave the system. A plug (34) is also included to prevent fluid communication between the filtered- and unfiltered-fluid outlets within the bore (24) of the second filter head.

Abstract: An improved polymer processing system having a pair of filtration units and a diverter valve arrangement for directing the flow of molten polymers alternately through the filtration units includes an improved manifold for the diverter valve arrangement for positioning the filtration units at opposite sides of the diverter valve arrangement allowing connection between the diverter valve arrangement and the filtration units with relatively shorter connecting pipes. The improved polymer processing system also includes an improved vent valve arrangement extending through the lid of the filtration unit and a means for introducing gas into an inactive filtration unit for speeding the draining of the polymer from the unit. The improved polymer processing system also includes a means for protecting the annular seal of the inlet port of each filtration unit during the process of reinstalling the filter vessel into the surrounding jacket.

Abstract: A closed type water storage container with water level controller and air filtering device, wherein the closed type water container is linked to the water level controlling device by a connection tube and the connection tube is provided with filtering materials for filtering of the moving water at the water level controlling device, such that water and air within the storage container are filtered and clean.

Abstract: A flow detector that can be effectively used in a clean environment (e.g., a semiconductor fabrication apparatus) and that enables the flow to be measured and regulated by an integrated apparatus. The flow detector includes a detector body having a fluid channel penetrating its interior and having a detection section of a flow sensor disposed in the fluid channel; and input and output blocks having input and output channels in communication with the fluid channel in the detector body. A flow control valve is provided in the output block. The detector body and each of the input and output blocks are joined together via seal members that seal the channels provided in the body and blocks and are fixedly connected at positions separate from the channels using screws.

Abstract: A valve filter is provided particularly for a balanced pressure valve and provides a means of preventing particles passing, through the balance holes of the valve plug.The valve comprises a valve housing and a valve plug movable in the housing to open and close the valve, the valve plug containing at least one balance hole, the balance hole defining a fluid communication channel through the valve plug, the fluid communication channel being provided with a filter, the filter comprising a body member and a plurality of elements, each element having a first end and a second end and being fixed at its first end to the body member and being, free at its second end, whereby the elements can deflect under pressure.

Abstract: A flush valve includes: a valve body having a diaphragm valve flexibly formed in the valve body communicated with an inlet pipe for supplying inlet water and an outlet pipe connected to a toilet, a urinal or a sprinkler system, a filter and a magnet mounted in the diaphragm valve for filtering out the dirts or rust carried in the water, a limit valve formed in the valve body juxtapositioned to the diaphragm valve for automatically closing the relief vents and passages between the diaphragm valve and the outlet pipe in case of failure of a manual relief valve or an electrically operated relief valve, which controls the opening or closing of the diaphragm valve, with the manual relief valve operatively opening the relief vents or passages at the downstream side of the diaphragm valve in a pre-set time period for timely opening the diaphragm valve, and a self-regulating valve provided in the outlet pipe for automatically maintaining a constant water flow rate when subjected to a fluctuated water pressure in a pl

Abstract: A coupling is provided having filters in the coupler and/or the nipple members. The coupler filter resides in the inlet to the coupler and the nipple filter resides in the inlet to the nipple member. The coupler and the nipple filters are easily replace due to their locations and the means employment to secure them in place. The coupler and the nipple filters are strength stainless steel filters having pores in the range of to 250 microns.

Abstract: Dangers of catalyst removal are decreased while the efficiency of the process is increased by provision of a new nozzle. The nozzle is two concentric pipes connected at one end, with the inner pipe extending slightly beyond the outer pipe at the other end. The outer pipe has orifices provided at the connected end which communicate with the exterior of the outer pipe and the space between the inner and outer pipes. A vacuum is pulled on the inner pipe which, in turn, causes gas to enter the space between the inner and outer pipes via the orifices. As the gas sweeps around the end of the inner pipe, it entrains catalyst particles and carries the particles into the inner pipe. The inner pipe extends beyond the reaches of the outer pipe to a distance such that the angle formed between the ends of the inner and outer pipes is approximately equal to the angle of repose of the catalyst.

Abstract: Valved couplers and gas processing components particularly suitable for ultra-high purity gas distribution for use in semiconductor manufacturing. In the couplers, a valve stem/bullnose seals the aperture of the coupler immediately adjacent the exterior of the coupler, so that only a minimal amount of the wetted surface of the coupler is exposed to the external environment. A gas processing component (e.g., a filter), or an entire integrated gas stick assembly, may be sealed from the exterior environment at both its inlet and outlet sides, by these valved couplers. As a result, the entire device can be purged after manufacture and left in a controlled environment during shipment and installation, reducing the need for purging after installation.

Abstract: An apparatus for cleaning a separator is disclosed. Generally, the apparatus includes a vessel connected to a well that produces an effluent. The vessel is used for separating the effluent. Also included is a discharge member which is attached within the vessel for discharging a liquid onto solids located at the bottom of the vessel, and a drain adapted for draining the solids from the bottom of the vessel. The apparatus may further include a chemical injection device, operatively associated with the discharge member, for injecting a radioactive dissolution chemical. A process for cleaning the vessel and treating the entrained solids of the effluent with the radioactive dissolution chemical is also described.

Abstract: The invention relates to a valve arrangement which can preferably be used in connection with a removal system comprising digester screens for digester liquids in cellulose digesters. The valve is characterized by a housing (1) with inlet openings (7) for digester liquid from each screen and at least one outlet opening (5) for the digester liquid from the screens and also at least one inlet opening (8) for digester liquid intended for back-flushing the screens and a rotor (10) in the housing (1) which is designed to shut off intermittently at least one of the inlet openings (7) from the screens and instead open the latter for the liquid for back-flushing.

Abstract: A unitary cup-shaped grid member having a grid of holes in the closed end is inserted in the inlet of a valve and a cup-shaped fine-mesh primary filter screen inserted therein and snap-locked in place. In the event the screen clogs and is removed by the user, the grid provides some back-up or auxiliary course filtering to protect the valve in service after removal of the primary filter screen.

Abstract: An apparatus for metering fluids is disclosed which comprises: a solid block having within the block a first fluid inlet; a filter assembly; a first fluid outlet; a first channel connecting the first fluid inlet to the filter assembly, and further connecting the filter assembly to the first fluid outlet; a second fluid inlet; a check valve assembly; a second fluid outlet; a second channel connecting the second fluid inlet to the check valve assembly, and further connecting the check valve assembly to the second fluid outlet; and a fluid meter connected between the first fluid outlet and the second fluid inlet.

Abstract: An apparatus to change and recondition a coolant of a car having a radiator, an engine block and a top hose connecting the radiator and the engine block. The apparatus having a valve to be received in the top hose. There is an inlet and an outlet pipe to be connected to the valve. A pump is connected to the inlet pipe and to the outlet pipe. There are tanks, each having an inlet and an outlet, to receive coolant from the pump and to supply coolant to the pump. These tanks also act to store reconditioned coolant and to receive coolant to be reconditioned. Valves direct coolant flow to one or other of the tanks as required. Using the apparatus coolant can be withdrawn from the radiator, pumped to a first or second tank, reconditioned in that tank, passed to the other of the two tanks and then returned to the engine block.

Abstract: A bypass line is provided to return an excess portion of working oil, whose pressure has been regulated by a regulator valve, to a suction side of an oil pump from a point between the regulator valve and a torque converter pressure regulator valve. An oil filter is inserted in the bypass line.

Abstract: A faucet strainer for preventing debris carried by a dispensed fluid from clogging or jamming the faucet assembly. The faucet strainer includes a strainer body and a debris receptacle. The strainer body includes a straining mechanism which allows fluid to pass therethrough but prevents debris carried by the fluid from passing therethrough. The debris receptacle, which is disposed along a fluid dispensing flow path downstream of the straining mechanism, collects the fluid carried debris prevented from passing through the straining mechanism.

Abstract: An improved foot valve assembly for use with a water intake includes a bucket with an internal conduit having a connector for attachment to a water pump intake pipe at the base of the bucket. Ballast weight added to the bottom of the bucket provides stability. The intake of water occurs at the upper end of the internal conduit, through a vertically supported foot valve. A basket-fitted over the foot valve may support a fabric bag-filter.

Abstract: The invention is a dual tank dispensing system that provides for directional control of the fluid being dispensed. Flow may be diverted through various pathways in order to provide different flow modes including: normal delivery, backwashing, rinsing, and isolation of one of the tanks. A unique dual diverter valve unit provides for alternate flow arrangements through passages in a body that connect the two tanks to the source of water. Each valve is in connection with four passages and through rotation of these valves various pathways are created that lead the flow to be diverted through one or both tanks and through an outlet passage leading to the destination or through one of two passages that allow for either rinse or backwash. A detector may be used in connection with the control unit to determine that the filters are clogged and signals the system to being a backwashing operation.

Abstract: An apparatus (10) for controlling an automatic timer regulated sprinkler system; wherein, the apparatus (10) comprises a float member (60) disposed within a multi-stage screen member (30) secured within a receptacle member (20); and, wherein, the float member is operatively associated with a switch member (50) for controlling the flow of electrical current to the sprinkler system in response to the level of collected water within the receptacle member. Another apparatus (200) for controlling an automatic timer regulated sprinkler system; wherein, the apparatus (200) comprises a water-amount-responsive means (204) containing water absorbing material; and, wherein, the water-amount-responsive means is operatively associated with a switch means (203) for controlling the flow of electrical current to the automatic sprinkler system in response to the change in gravitational force or expansile force produced by water on the water-amount-responsive means.

Abstract: A combination noise suppressor and air filter fits closely around a pressure regulator for milking machines, in such tight-fitting sealed relationship that little or no air or dirt can enter except through a relatively large diameter washable air filter which can be removed and cleaned even while the milking machine is running. The air passing inwardly through such filter also passes through the bars of a cage which support the filter against collapse. A noise suppressor, formed of a laminate of rigid and soft synthetic resin, is provided, and has apertures therethrough through which air passes downwardly after entering through the air filter. After thus passing downwardly, the air is in a chamber that contains the inlet ports of the pressure regulator portion of the combination, the upper wall of the chamber having convolutions which cooperate with sound-absorbing side and bottom walls of the chamber to absorb sound that is generated when air enters into the regulator.

Abstract: A filtered vent useful for venting drums, such as 55-gallon drums, includes a cylindrical housing having an anular activated carbon filter cartridge disposed therein. The cylindrical housing has a threaded collar with vents at one end and a pressure relief valve at the other end. The pressure relief valve is connected to a J-shaped tube which has an open end positioned proximate the threaded collar. An annular filter is disposed in the housing, the annular filter has an inner surface in communication with an inlet connected to the pressure relief valve and an outer surface in communication with the vents in the threaded collar. Volatile liquid in the air space between the top wall of the container and the top surface of the liquid passes through the activated carbon filter before venting into the atmosphere. If nesessary or desired, a HEPA filter may be disposed upstream of the activated carbon filter and a GORTEX.TM.

Abstract: The present invention relates to a self-cleaning dosing pump system for delivering a slurry of solid particles and water. The dosing pump system comprises a membrane metering pump 10 and at least one sieve 11-13, arranged at the delivery end of the pump 10.

Abstract: A spool control valve in which communicating passages are provided in the spool to communicate between a pair of locations in the spool passage and filter means are provided in a communicating passage to prevent valve orifices being blocked by particles of foreign matter in the fluid.

Abstract: Methods and apparatuses for cleaning and/or muffling a gas discharge which in one aspect includes a hollow body with a filter element mounted therein through which the discharge gas flows and in which liquids entrained in the gas are filtered out, the body having one or more liquid collection areas from which liquid can be removed from the apparatus for disposal or for re-use. The apparatus also can serve as a noise muffler to reduce the noise level of the gas discharge.

Abstract: An automatic air valve for a conduit, through which passes fluids and/or solids, which valve prevents the discharge of contaminated air therefrom into the environment and which further permits the introduction of fresh air from the environment into the conduit when a negative pressure develops therein. The valves may be disposed at either the terminus of or interposed within the conduit flow line of a duct system. The valves include an interior filter that restrains foreign objects, such as insects and snakes, in the duct systems from operatively interfering with the proper operation of the valve.

Abstract: An automatic air valve for a conduit, through which passes fluids and/or solids, which valve utilizes a freely-movable valve member to prevent the discharge of contaminated air therefrom into the environment and to permit the introduction of fresh air from the environment into the conduit when a negative pressure develops therein. The air valves may be disposed at either the terminus of or interposed within the conduit flow line of a duct system. The air valves include an interior filter that restrains foreign objects, such as insects and snakes, in the duct system from operatively interfering with the freely-movable valve member. Means is also included for preventing the interior filter to move or to be moved into a position wherein the interior filter may operatively interfere with the freely-movable valve member. The interior filters are nonplanar in shape, so as to provide a total air passage area that is substantially the same as the air passage area that is present without the interior filter.

Abstract: There is disclosed a compressed air delivery system for delivering clean, dry, compressed air from a source of compressed air to a compressed air appliance. The compressed air delivery system includes a vertical, cylindrical tank with an inlet located in the lower 1/3 of the tank and an outlet located near the top of the tank so that the air in the tank becomes stratified with the light, clean air at the top. The inlet to the tank includes in series a connector connected to a source of compressed air, a stepdown regulator, a check valve, an inlet port, and an inlet tube filled with packing material. The outlet of the tank includes in series a drop tube inside the tank, an outlet port, a shut off valve, a particulate filter, a coalescing filter, a stepdown regulator, and an output coupler.

Abstract: An improved juice drainage system is incorporated into the mash line of juice processing equipment. Fruit or other mash is pumped through a relatively large-diameter, generally horizontal mash pipe. A plurality of relatively smaller-diameter tubes or juice drainage elements are inserted into and intersect the mash pipe in generally perpendicular orientation at selected points along its length. These drainage elements include screens or other openings forming a drainage surface, preferably on the "downstream" side of the elements, so that juice from the mash flowing through the mash pipe passes through the openings and into the drainage element. The size and shape of the openings can be designed to control the juice drainage rate from any particular drainage element. In addition, the drainage elements themselves can be specifically sized, placed, and/or oriented along the mash pipe to impart the desired mixing characteristics to the flowing mash.

Abstract: A sampling probe by means of which a sample of fluid free of particles or substantially reduced in particle content can be removed from a particulate matter-containing fluid stream which is flowing in a conduit. This is accomplished by means of probe geometry. Openings for entry of the sample into the probe face downstream. In one embodiment, the cross-section of a probe at the fluid entry area is V-shaped.

Abstract: A strainer device for railroad car air brake combined dirt collector and cut out cocks, and arranged to be applied within the swirl chamber of such cocks, and between the collector bowl, about the pedestal thereof, and the lip of the cock throat chamber, which strainer device comprises an outer shell that is open and flanged at both ends, with one end of the outer shell being disposed adjacent the throat lip, an annular seal applied between the said outer shell one end and the throat lip, an inner shell disposed within the outer shell and secured at the other end of the outer shell and adapted to receive the cock collector chamber pedestal, and a compression spring received about the pedestal within the cock collector bowl and resiliently seated against the outer shell end flange at that end of same for spring biasing the other end of the outer shell and the seal against the throat lip.

Abstract: An inlet flue system for conducting particulate-containing gases to the inlet nozzles of a multiplicity of electrostatic precipitator chambers comprises an elongated plenum located generally above the nozzles. The plenum is substantially entirely open at the bottom, and the inlet ends of the perimeter walls of branch ducts leading from the open bottom define a series of outlet openings from the plenum. The open bottom construction leaves the plenum substantially free of upwardly facing surfaces where particulates can settle.

Abstract: Arc suppressing gas in a high voltage circuit breaker system is collected, filtered and compressed. The compressed gas is passed through a series of oil and desiccant filters and returned to a high pressure vessel for storage. The oil and desiccant filtering system is combined in a single, separable casing including baffles and a check valve.

Abstract: A control valve is provided with an inlet and outlet port and a variable flow control arrangement therebetween. The variable flow control arrangement is comprised of a hollow spool member having a plurality of orifices disposed in a spiral manner along the length of the spool and a sleeve having an annular valve member in contact with the spool movable axially of the spool to selectively expose one or more orifices to a valve chamber in communication with the outlet port. The sleeve member is connected to a flexible diaphragm having a first surface exposed to an atmospheric pressure chamber within the control valve and a second surface exposed to a signal vacuum chamber adapted to be connected to a vacuum supply. Spring means are provided in the signal vacuum chamber for normally biasing the sleeve into a position covering all of the orifices in the absence of a vacuum signal within the signal vacuum chamber.

Abstract: An assembly connectable between a compressor and reservoir, having a filter unit capable of centrifugally cooling and separating condensed moisture and other contaminants from compressed air and discharging clean air in saturated condition at the outlet temperature and pressure, the unit being connected to the compressor through an inlet valve opening when the compressor begins pumping and to the reservoir through a pressure regulator valve adjustable to open only when the air in the unit reaches a predetermined pressure, which, for minimizing the absolute moisture content of the clean air passed to the reservoir, usually will be substantially maximum reservoir pressure.