Abstract: A water supply system includes a motor operated pump (12) which provides water upon demand to a remote location via a discharge pipe (13). When the demand 5 ceases, the pump (12) continues to operate to provide water to an annular chamber (21) which is under air pressure. The annular chamber (21) is formed by a storage pipe (20) generally concentrically positioned around the discharge pipe (13). A pressure switch (17) senses the water pressure in the discharge pipe (13) and stops the pump when a first predetermined pressure level is reached. Then upon the next water demand, water is provided from that in the storage pipe (20) until a second predetermined pressure level is sensed by the switch (17) at which time the pump (12) is activated to provide water through the discharge pipe (13). An air volume control unit (45) maintains the proper air pressure in the annular chamber (21).

Abstract: A method for controlling the filling of a filter press with slurry according to a preferred embodiment of the present invention includes the sequentially executed steps of: gradually increasing the pressure of the slurry supplied to thee press until the slurry pressure reaches an upper pressure limit; recording a trigger point in time at which the slurry pressure reaches the upper pressure limit; and determining whether the slurry pressure subsequently falls below a lower pressure limit within a predetermined period of time commencing at the trigger point. If the slurry pressure does fall below the lower pressure limit within the predetermined period of time, then the above-listed sequence of steps is repeated until the slurry pressure fails to fall below the lower pressure limit within the predetermined period of time, thereby indicating that the press is full and terminating the process.

Abstract: A portable, inflatable support system, and a portable inflator for use with such a system are provided in one embodiment. The inflatable support system may include an inflatable mattress having a pressure valve and a battery powered inflator for removable engagement therewith, which on engagement is automatically powered for a predetermined time or until a predetermined pressure is achieved. The mattress may be readily expanded for use and collapsed for storage. Another embodiment provides a multipurpose pressure control, for manual adjustment to provide an inflatable support system of desired firmness, and to modify the posture of the reclining user. Another embodiment provides an in-place bedding system, including a mattress, mattress cover, and top and bottom bedsheets, which retain their functional arrangement when the bed is collapsed for storage and prepared for use, thereby eliminating the necessity for re-making the bed with each use.

Abstract: A reverse osmosis water purification system that incorporates a high torque low speed motor to drive a pump, such that the pump can continuously pump water from a source of water to an osmotic membrane The system may have a reservoir to store the purified water as it is pumped through the osmotic filter. The system can also have a transformer and rectifier to convert and rectify an alternating electrical power source to 24 volt DC power for the motor. The transformer having a higher impedance than the motor such that the transformer acts as a current limiter in the event the motor stalls. The pump has an internal pressure relief valve Operatively connected to the inlet of the pump housing. The relief valve opens when the output pressure of the diaphragm piston reaches a predetermined valve. The relief valve allows the high pressure water to flow back into the housing inlet creating a flow loop from the inlet back to the water source.

Abstract: An apparatus for on/off controlling a pump in a water distribution network, which ensures a practically constant pressure through the distribution network, comprises, within a body, a chamber having an inlet conduit adapted for connection to the delivery side of the pump and an outlet conduit adapted for connection to the network, a pressure switch placed in said chamber to issue a start signal to the pump at a predetermined pressure setting, and a flow switch placed in the outlet conduit to issue a start signal to the pump upon the occurrence of a predetermined minimum flow or a stop signal to the pump in the event of the flow being interrupted.

Abstract: An electrohydraulic pump load control system that includes a fluid-cooled integrated electric motor/hydraulic pump for delivering fluid under pressure to an accumulator that stabilizes pump output pressure while accommodating changes in fluid flow. A pressure sensor is coupled to the accumulator to provide an electrical signal as a function of fluid pressure at the accumulator. An electronic controller applies electrical power to the pump motor, and is responsive to the electrical signal from the pressure sensor for terminating application of electrical power to the pump motor when pressure at the accumulator reaches the desired threshold. The electronic motor controller controls both application and termination of electrical power to the motor to energize and de-energize the motor at predetermined rates responsive to pressure differential thresholds at the pressure sensor.

Abstract: A combined air vent and pressure switch are provided at the inlet of a liquid pump. The air vent is adapted to exhaust air from a supply line, such as a garden hose, and thereby substantially prevent the pump from running dry before water from the hose reaches the inlet. The pressure switch is connected to the motor of the pump and is adapted to signal the motor to stop if the pressure switch senses a low pressure condition at the pump inlet, such as when there is inadequate liquid or no liquid at the pump inlet. The features of the air vent and pressure switch combine to prevent the pump from being damaged by running the pump without adequate liquid supply.

Abstract: A hydraulic power unit for a vehicle comprises a motor, a pump to be driven by the motor to pump up an oil stored in an oil tank, a gas filling type accumulator connected to the pump, a pressure sensor disposed at a portion near an outlet port of the accumulator for detecting a pressure of the oil in the accumulator, a control unit operatively connected to the pressure sensor and a relay opertively connected to the control unit for controlling an operation of the motor.

Abstract: A reverse osmosis water purification system that incorporates a high torque low speed motor to drive a pump, such that the pump can continuously pump water from a source of water to an osmotic membrane. The system may have a reservoir to store the purified water as it is pumped through the osmotic filter. The system can also have a transformer and rectifier to convert and rectify an alternating electrical power source to 24 volt DC power for the motor. The transformer having a higher impedance than the motor such that the transformer acts as a current limiter in the event the motor stalls. The pump has an internal pressure relief valve operatively connected to the inlet of the pump housing. The relief valve opens when the output pressure of the diaphragm piston reaches a predetermined valve. The relief valve allows the high pressure water to flow back into the housing inlet creating a flow loop from the inlet back to the water source.

Abstract: A pressure supply system for a vehicle according to the invention incorporates a pump and an accumulator in which an output pressure of the pump is maintained within a prescribed range by controlling the on-off operation of the pump according to the inner pressure of the accumulator. By changing the prescribed range of pressure according to the actual pressure requirement, for instance according to the change in the travelling speed of the vehicle, the burden on the system is reduced. The prescribed range can be changed either by simply changing the upper and/or lower pressure limits at which the pump is deactivated and activated, respectively, or by operating the pump for a prescribed time period which is dependent on the pressure requirement after a certain reference pressure value is reached. Thus, the structure of the fluid pressure system is simplified, and the generation of unnecessary high pressure can be avoided.

Abstract: A hydropneumatic arrangement is provided for actuating a pump upon pressure decrease and for deactivating the pump upon flow decrease. The hydropneumatic arrangement includes a bearing cylinder; a flow sensor piston movably disposed within the bearing cylinder; a driving piston connected to the flow piston by a common shaft, the flow sensor piston being moved according to a variation in consumption demand by an interaction of a force of flow exerted against the flow sensor piston and a force of pressure exerted on the driving piston. A pressure switch is provided and is electrically connected to an electric motor that drives the pump.

Abstract: A sewage pumping system includes a container, an inlet for the inflow of liquid and a modality for ascertaining the liquid level in the container. Two or more pumps are provided, each having an inlet communicating with a container and an outlet communicating with the common conduit. A pump controller receives information from the modality for ascertaining the liquid level and is adapted to start and stop individual pumps. A pressure sensing device is located in the conduit for sensing the backpressure against which pumps in operation are pumping, and for generating a second signal corresponding to the sensed backpressure, the signal going to the pump controller. An addressable memory is operatively connected with the pump controller and stores values corresponding to pumping rates vs. backpressure for each of the pumps, along with high and low backpressure values for each pump. On high backpressure the pump controller avoids pumpstarts which will not result in a net increase in the total pumping rate.

Abstract: A sump apparatus for use in a marine vessel comprises a tank, a pump communicating with the tank for evacuating the tank, and a pump control mechanism for energizing the pump in response to a predetermined height of water in the tank. That mechanism comprises a housing defining an air chamber, a switch disposed in the chamber and operably connected to the pump, a switch actuating diaphragm mounted in the housing for actuating the switch. An air vent conduit communicates with the chamber, and a flow restrictor desensitizes the diaphragm relative to momentary changes in the water pressure acting on the diaphragm. The pump control mechanism can be mounted in a side wall of the tank, or to a removable top lid of the tank so as to be removable with that lid. The pump control mechanism may include a timer operably connected to the switch and pump for deactivating the pump after a predetermined period of pump operation sufficient to evacuate the tank.

Abstract: The temperature-dependent pressure detection switch according to the present invention comprises a pressure receiving member to receive hydraulic pressure, on which spring force of the predetermined value is permanently applied to the direction reverse to the operating direction of said hydraulic pressure and the spring force is varied according to temperature change, and a switch unit, which is operated by the movement of said pressure receiving member against said spring force when predetermined hydraulic pressure is received. Accordingly, when ambient temperature changes, spring force is changed, and the switchover setting pressure related to the on-off switchover operation of the switch unit can be changed according to temperature change. Namely, the pressure detection switch can be provided with temperature-dependent property.

Abstract: An apparatus for conveying paints is connectible via a supply passage to a reservoir and is connectible via a feed passage to an application device. The apparatus includes a diaphragm pump mounted in a closed housing and provided with an admission valve and a discharge valve. The diaphragm pump is driveable with an electric motor that can be switched by a manometric switch dependent on conveying pressure. The admission valve and the discharge valve are commonly arranged in a pump head and are held by a supporting element that is detachably connected to the pump head. Further, the discharge valve is located upsteam of a pressurized chamber that is connected to the feed passage and is also located in the pump head. Variations in feed passage pressure cause variations in the volume of the pressurized chamber by flexing a control diaphragm. The control diaphragm acts on an adjustment element to actuate a control switch. The invention provides an apparatus that is compact, reliable, and easy to manufacture.

Abstract: An improved dome structure on a base is disclosed comprising, in the preferred embodiment, of a membrane sandwiched between layers of rigidifying material such as shotcrete or reinforced composite which also serve to embed radial wires and circumferential tensioned prestressing. Various types of circumferential tensioned prestressing can be applied to minimize bursting stresses and can consist of steel wire as well as fiber or steel-reinforced tape. Further layers of rigidifying material can then be applied over the circumferential prestressing as a final protection and cover. The radial wires can contain spacers or hooks to preclude the circumferential prestressing from riding up on the structure. The lower portion of the dome can include a reverse curvature to minimize stresses and stabilize the structure. The rigidifying material may be composite which can be hardened by light curing. A second outer membrane can also be used for weather protection.

Abstract: A pneumatic device for detecting continuously the hydrometric level of a water column, said device comprising a tubular probe dipped into the liquid column by a height greater than the distance between the two maximum and minimum levels set forth previously, a pair of pneumatic detectors of the minimum and the maximum level which are operatively associated to said probe and are put in action by changes in the air pressure occurring inside the probe itself as a function of changes in the column level, a gauge or indicator associated to the maximum level detector for signaling continuously the position of the water level, and means for starting or for stopping a motor-driven pump in correspondance to said maximum and minimum values.

Abstract: A pump supply system for furnishing well water or the like which is sensitive to and operates within a range defined by a pressure switch to supply water when pressure in the system falls below a preset minimum pressure and shut off the pump when the pressure reaches a predetermined value. Timing means is employed in the system and preset to time out after a predesignated interval of operation of the pump. The system will retime the next pumping cycle, if that interval of operation is not exceeded. If the pump seeks to operate beyond the predesingated time period, the timing circuit is disabled, the pump is shut down, and an alarm is activated.

Abstract: An underwater frazil ice detector is disclosed comprising channel means disposed underwater for moving water therethrough, means for drawing water through said channel means, screen means disposed in and across said channel means so that water drawn therethrough by said water drawing means passes through said screen means, pressure detecting means disposed in said channel means and downstream of said screen means for detecting pressure differential across said screen means, whereby flow of water through said screen means is constricted when frazil ice forms thereon, creating an increased pressure differential across said screen means and thereby indicating the presence of frazil ice.

Abstract: A system for automatically controlling the pressure maintained in a plurality of fluid-filled cylinders supporting a sleep surface in order to maintain a desired degree of firmness/softness. In one mode, the system permits the user to set the desired level of firmness and then the system acts to maintain that level under the conditions encountered in use, either venting if an above-setting pressure is sensed or pumping to fill if a below-setting pressure is detected. In another mode, the user is enabled to manually activate either the pump or the vent in order to vary the firmness to his choice.

Abstract: A mechanical pressure switch is provided which includes a conduit that is expandable and contractable in response to the pressure of fluid passing through the conduit. A switch is mounted in a fixed position relative to one portion of the conduit and an actuator is mounted in a fixed position relative to a second, spaced portion of the hose such that the switch will be mechanically activated and deactivated by movement of the actuator relative to the switch in response to pressure changes in the conduit. Preferably the relative positions of the actuator and switch are adjustable in the same direction as the expansion and contraction of the conduit.

Abstract: In a suction apparatus (1) for sucking up wet and/or dry suction material there is a single suction chamber (6) having an approximately constant inside diameter over its entire height forming in the bottom region a preseparating chamber (9) for heavier parts and optionally liquid, as well as spaced above the same in the top area a filter chamber (10) for receiving a wet or a dry filter (11) for filtering before or after the preseparation. The main container (2) forming the suction chamber (6) and to be opened level with filter (11) is immediately adjacent to an electromotive exhauster unit (3) relative to which it can be tilted for emptying the preseparation chamber (9). So that the filter (11) is not subject to liquid or heavier parts to be preseparated, there is an adjustable fill level limiting device (25) with a limit switch (26) directly responding to the suction material, which switches off when the exhauster unit (3) responds and then automatically switches in again.

Abstract: A control system for a pump includes a level sensor switch that is positioned along a production string in an oil well shaft (S). The level sensor switch is protected from damage by inner and outer housings. A control circuit responsive to the level sensor switch is also provided. The control circuit includes an adjustable timer that is located at ground level remote from the harsh environment of the oil well shaft (S). The timer controls the operation time of the pump during each pumping cycle.

Abstract: A bottled water supply system comprises a base unit into which a standard five gallon water bottle may be installed. The cover of the base unit supports the bottle in an inverted position such that the neck of the bottle projects into a water reservoir within the unit. A pump, also housed within the unit, draws water from the reservoir and pumps it to the water supply line of an appliance. Power for the pump is controlled by a pressure actuated switch so that the pressure in the supply line is maintained a predetermined level. A pair of magnetic reed switches are housed within a water tight tube in the reservoir below the normal water level. A magnetic float surrounding the tube actuates one of the reed switches when the water level falls below the neck of the water bottle, thereby actuating an alarm indicating that the bottle is empty. The second switch is actuated just before the water level drops to the level of the pump supply tube and interrupts power to the water pump.

Abstract: A waste water collection and discharge system includes a buried waste water collection container which receives solid and liquid waste through an inlet. A dry vault located outside the container has a closable entryway which permits access to the vault from above ground. A pump which fits in the vault has an inlet which receives waste water from a fluid inlet tube that extends into the collection container, and an outlet which passes waste water through a fluid outlet tube to a remote collection site. A level sensor senses the level of the waste water in the collection container and initiates and terminates operation of the pump to maintain the level within predetermined limits. The pump, motor, level sensor and motor control system are interconnected into a unitary module which can be placed into and removed from the vault from above.

Abstract: A switch mechanism for controlling a motor that runs a well pump. Water line pressure acts on a diaphragm to pressurize an air chamber that communicates with a pressure switch. The switch components are isolated from the water line (by the air chamber), to minimize the possiblity of switch failure due to ice formation (winter time operations) or corrosion.

Abstract: A device for automatically disabling operation of a pneumatic device, such as an air-actuated pump switch. The device includes a diaphragm exposed to atmospheric pressure on one side and to water pressure on the other. So long as the water pressure is high enough, the diaphragm is held in a position in which it seals a pneumatic port and ensures continuing operation of an air-actuated switch. If the water pressure falls below a preselected level, the port is vented to atmosphere and the air-actuated switch is effectively disabled until the water pressure increases again.

Abstract: A control system of pumping operation comprises a cycloconverter for converting AC power from a AC power system into AC power having a given frequency, anAC exciting generator-motor, having a stator side electrically connected to the AC power system, having a rotor side electrically connected to the cycloconverter, and having a rotor shaft mechanically coupled to a pump-turbine by which the pumping operation is carried out, a circuit breaker inserted between the AC power system and the AC exciting generator-motor, a rotation speed controller for controlling a rotation speed of the AC exciting generator-motor such that the rotation speed becomes slow when the pumping operation is to be stopped, an AC excitation controller for decreasing a degree of excitation effected by the cycloconverter, wherein decreasing of the excitation degree starts when the rotation speed of the AC exciting generator-motor reaches a given minimum value, and a circuit breaker controller for turning off the circuit breaker when input po

Abstract: A control system and method is disclosed for a plaster pump 10. A pair of nozzles A, B dispenses material pumped from the nozzle and are connected by a "Y"-branch 50 in supply lines 11a and 11b to pump manifold 10a. Actual pressure signals 14a are compared in a comparator 16 to preset pressure signal 28. A differential pressure signal 16a is delivered to a signal switch 34 which controls a throttle driver 38 to control throttle 40 and pump 10. The pump may be throttled up or down to satisfy the pressure difference and bring the pressure to the desired preset pressure. An actual pressure signal 14c is delivered to an overpressure comparator circuit 26. An upper pressure limit signal 28a is compared to actual pressure by comparator 26. If an overpressure condition exists, an overpressure signal 26a is sent to signal switch 32 which shuts off or idles down the pump. If either nozzle A or B is shut off, a nozzle-off signal at 64a is sent to logic controller E.

Abstract: A device for detecting partial restriction in a fluid line connecting a fluid source with an IV infusion pump comprises a gauge mounted on the pump and operatively associated with the line to determine fluid pressure therein. The pump also comprises a peristable finger to conditionally occlude the line and a miroprocessor, upon occlusion of the line, to establish fluid pressure parameters within which the indication is that there is no partial restriction in the line. The pump also uses the microprocessor to compare actual pressure measured by the gauge during an occlusion with the established parameters to determine whether pump operation is to be continued.

Abstract: In a method and device for the application of foamed or non-foamed flowable substances upon a substrate, where the quantity of the substance to be applied in function of the surface units to be coated is preselected, the flow rate of the material dispenser to the applicator is controlled by a control element and the quality of application is insured by measurements of the application pressure.

Abstract: A liquid dispensing system and a unified assembly for control of fluid flow in such a system has a container 1 from which liquid such as beer is drawn by an electrically controlled pump 2 to be supplied through a unified assembly 4 to a dispensing tap 5. The assembly 4 has an inlet 6 which communicates through a pressure biased non-return valve 8 with a high pressure chamber 9 and an outlet 11 to the tap 5. A piston 14 responds to high pressure in the chamber 9 to be displaced and pivot a rocking lever 26 to operate a microswitch 28 which is normally closed to operate the pump 2 but is opened in response to said displacement of the piston 14 to deactivate the pump 2. A low pressure chamber 35 communicates with the inlet passage 6 and the pressure of liquid in the system expands the chamber 35 to maintain a plunger 38 against its spring biasing.

Abstract: A ventilator apparatus comprises a pump; a delivery conduit for delivering pressurized air to a patient; a relief valve preventing the pressure in the delivery conduit from rising above a predetermined peak value; a sensor for sensing the pressure in the delivery conduit; a storage device for storing the sensed peak pressure; and a comparator for continuously comparing the sensed pressure with the stored peak pressure and effective to energize the pump whenever the sensed pressure is below the stored peak pressure, and to deenergize the pump whenever the sensed pressure is generally equal to the stored peak pressure.

Abstract: A liquid flow system comprising a bidirectional liquid pump, a bidirectional electric motor coupled to drive the pump, and a liquid flow line having the pump connected therein. The system further comprises a motor control circuit connected to power the motor in either the forward or the reverse direction. The control circuit includes a switch for connecting the motor windings to the power lines, the switch being operable to instantly reverse the power connections when the motor is operating in the forward direction and thereby powering the motor-pump to an instant stop and then immediately powering the motor in the reverse direction. The pump thereby instantly reverses the liquid flow in the flow line and abruptly terminates the flow. To quickly start the flow again in the forward direction later on, a priming loop is connected to the pressure side of the pump, so that the pump is able quickly to develop pump pressure.

Abstract: A back pressure sensor comprising a flexible beam having a pivot end with a pivot pin and a drive connector end with a means for engaging a pump drive. A pump actuator is connected to the flexible beam at a position intermediate the ends and connects with a positive displacement pumping member. A sensor beam is attached to the flexible beam at a connecting point spaced from said pivot end. A first capacitor plate is mounted on the flexible beam at a point which is spaced from the connecting point. A second capacitor plate is mounted on the sensor beam in a position facing and spaced apart from the first capacitor plate at a distance therefrom which permits formation of a capacitance coupling therebetween.

Abstract: A gas driven pump (102) is controlled by an asynchronous controller (101). The controller (101) has two control conduits (105,103) respectively in communication with the bottom and top regions of the chamber of the pump (102). Low pressure air is bubbled through the control conduit (105) in communication with the bottom region of the pump chamber; therefore, the pressure in that conduit, which is applied to the face top of the diaphragm (111), in a direct function of the depth of the liquid in the pump chamber. The other control conduit (103) is in communication with the bottom face of the diaphragm (111). When the difference of the pressures in the control conduits (105,103) exceeds the bias of the spring (114), the diaphragm (111) and the attached spool (128) move downward to activate a mechanically operated pilot valve (144). The pilot valve, in turn, releases supply air under pressure to switch the main valve (145) from the rest state to the operated state to initiate discharge of liquid by the pump.

Abstract: A detector for determining when an occlusion has occurred in the fluid line of an IV administration set comprises means associated with an IV infusion pump to determine the resistive force exerted by fluid in the line against the pumping mechanism of the pump. The detector includes a flexible beam which is mounted between the plunger and the activator of the pumping mechanism and which bends proportionately to the magnitude of the resistive force. A strain gauge attached to the beam activates an alarm which stops the IV pump when flexure of the beam indicates an occlusion in the line has occurred.

Abstract: A washing machine includes a tub having a water collecting well, a water suply conduit provided with a controllable valve for supplying water to the well during at least one water supply phase of the operation of the washing machine, and a circulation pump for circulating water collected in the well during at least a latter portion of the supply phase. A control system automatically controls operation of the valve and thereby the supply of water to establish a minimum water level within the well required for optimum operation of the circulation pump. The control system includes a control chamber and an overflow wall having a predetermined overflow level and communicating the well with the control chamber, such that when the level of water in the well reaches the overflow level the water overflows the overflow wall into the control chamber.

Abstract: A regulation system controls the print head pressures of a plurality of discrete ink jet printers of the continuous type to the same nominal pressure, while the printers use a common drive source to their own ink pumps. The regulation system includes bypass pressure detection passages extending from a tap in each printer's circulation system to a detection reservoir. Each bypass passage includes a bladder/valve portion whose exterior is in fluid communication with a detection fluid enclosed within the common reservoir. A transducer detects the pressure of the common reservoir and signals control of the common pump drive so as to regulate all print head pressures to the same nominal operating pressure.

Abstract: A fluid sampling apparatus is disclosed for withdrawing samples of groundwater or other fluids from a well or other monitoring site. The apparatus preferably includes pump means, conduit means and a wellhead assembly that are substantially permanently installed at such well or monitoring site and are thereby dedicated thereto in order to avoid or minimize cross-contamination of samples from site to site. The apparatus preferably also includes a removable and portable controller means adapted for easy and convenient transportation and connection to such dedicated fluid sampling components at various wells or monitoring sites. A recovery, collection and control system for cleanup of leachate or other liquid material or contaminated groundwater from a landsite is also disclosed.

Abstract: Sensor circuitry is disclosed for a transducer (32) having a sensor or delta coil (66) for generating a magnetic flux through a path of movement of a magnetically permeable piston member (48), such that movement of the member (48) changes the return coupled flux linkage, which flux change indicates movement of the member (48), and having a reference coil (84) spaced sufficiently from the path of movement of the member (48) such that movement of the latter has less affect on return coupled flux linkage of the reference coil (84) than the delta coil (66). The coils (66 and 84) are connected (204) in respective parallel voltage dividers, and a half-wave rectified AC signal (diode CR11) is applied thereto.

Abstract: An apparatus for monitoring the level of water being pumped into kitchen sinks, laundry tubs, and standpipes. The apparatus features a novel fluid levels ending unit operatively connected to a novel control unit for providing maintained termination of electrical power to the pump motor, should the water drainage system become clogged. As water flows through the nozzle of the sending unit, it operates to seal off the nozzle's air chamber inlet to trap and contain air therein. Therefore, should the drainage system become clogged, back-up water rises to a predetermined height within the air chamber. In so doing, the trapped air within the air chamber becomes compressed to a predetermined small value, for actuating the pressure switch. The actuated pressure switch in turn provides an electrical signal to the control unit for termination of water pump action.

Abstract: A rheostat of the kind that comprises a tank containing electrolyte and at least two electrodes, one electrode being connectable to an electric power supply and the other electrode being connectable to apparatus to be fed by the power supply. The electrodes define therebetween an electrolyte flow path and there is associated with the electrolyte flow path operational pumping apparatus providing for a controlled effective circulation of the electrolyte between the electrodes. The rheostat is particularly usable in conjunction with the starting of squirrel-cage motors.

Abstract: A control system for a pump submersible in a well having a water pipe extending upwardly to a water source includes an isolation element that has one fluid chamber in communication with the water pipe and another chamber separated from the first by a flexible diaphragm. The second fluid chamber is filled with a non-toxic antifreeze control fluid and communicates with a fluid conduit which extends upwardly to a pressure switch. The pressure switch is mounted above-ground and monitors the pressure of the control fluid to activate and deactivate the pump. Since the diaphragm is flexible, the pressure of the control fluid corresponds to the water pressure in the water pipe. The isolation element is positioned in the well below the frost line so that all control parts in contact with water are located below the frost line, and all control parts located above the frost line contact only the antifreeze solution.

Abstract: A hydraulic booster including an input piston adapted to be actuated by a manually operated member such as a brake pedal. The input piston is axially slidable in a power piston which is in turn axially slidable in a booster casing. The power piston divides the inside cavity of the casing into a power chamber and a reservoir chamber. An electrically operated plunger pump is provided and has an outlet port connected with the power chamber and an inlet port. Between the input piston and the power piston, there are defined a first valve and a second valve. The first valve functions to open the power chamber to the reservoir chamber when the pedal is released but to disconnect the power chamber from the reservoir chamber when the input piston is depressed by a first predetermined distance.

Abstract: A pump operable in response to the level of the liquid to be pumped comprising an impeller, a motor for rotating the impeller, a discharge passage for receiving the liquid pumped by the impeller, and a sensing chamber communicating with the discharge passage between the impeller and the pump outlet so that liquid in the discharge passage can trap gas in the sensing chamber. A pump controller is responsive to the pressure of the trapped gas in the sensing chamber for energizing and di-energizing the motor. Energizing of the motor to cause the impeller to pump liquid into the discharge passage substantially increases the pressure of the trapped gas to thereby assure that the pump remains on.

Abstract: To protect the pump of a whirlpool bath against running dry and against blockage at the inlet, a pressure (or flow) sensor 14 senses pump pressure and generates a signal to keep a switch S2 in the pump motor electrical supply circuit closed. If the pressure signal ceases owing to blockage or running dry, the switch S2 opens. A manual override button 15 is held ON to close switches S1a and S1b in the power circuit for start-up. The sensor 14 and manual button 15 are preferably air pressure devices. Switch S1a is preferably an air-signal-operated latching switch whereby with the pump operating, the button 15 can be operated to switch the pump off. Relays RLA 1 and 2 may be used in conjunction with the electrical switches. A bleed hole may be provided between the button 15 and switch S1b to limit the period of time for which the motor could be run, with the bath empty, by prolonged inadvertent actuation of the button 15.

Abstract: A power assisted respirator comprises a facepiece for covering at least the nose and mouth of the wearer which has an outlet provided with a one-way exhale valve which is openable to permit air to flow out of the facepiece when a predetermined pressure P is established within the facepiece. A pump unit supplies air to the space within the facepiece. The pump unit may be connected to an inlet of the facepiece by a flexible hose or may be mounted directly on or in the facepiece. A filter canister is connected to the inlet of the pump means for filtering air supplied to the facepiece. A one-way inlet valve is provided in the path of air flowing from the pump unit to the facepiece and a pressure sensor is provided for sensing the pressure of air in the region of the pump unit inlet for causing deenergisation of the pump unit when the pressure in the region of the pump unit inlet exceeds a predetermined level.

Abstract: Disclosed is a method of controlling the operation of a plurality of compressors each having at least one capacity controller capable of changing the discharge rate of the compressor in a stepped manner in such a manner as to provide a total discharge rate just meeting the load demand which varies momentarily. In this method, the control system is divided into a capacity control loop for responding to comparatively small load variance and a compressor control loop for responding to a comparatively large load variance. The capacity control loop is further divided into a sub-loop for capacity controllers of a compressor which has worked longest and which is to be stopped first and a sub-loop for the capacity controllers of other compressors. The unloading operation is commenced preferentially with the sub-loop for the capacity controllers of the compressor to be stopped first, while the on-loading operation is made first with the sub-loop for the capacity controllers of other compressors.

Abstract: The invention involves positioning the working end of a vertical pump below the surface elevation of the fluid, enclosing a space around the pump with a structure extending below the surface and having a submerged opening to the main reservoir, and drawing a vacuum in the enclosed space in order to raise the surface elevation in the enclosed chamber in order to maintain a minimum working depth for the vertical pump that will prevent air entrainment by vortexing during periods of low fluid levels outside the chamber.