Abstract: A three-way tubing includes an outlet, an inlet and an opening communicated with one another, a valve is pivotally supported in the tubing and includes a board and a panel perpendicular with each other, when water flows from the opening to the outlet, a force may act on the panel such that the board is forced to close the inlet and such that water is prevented from flowing through the inlet, when water flows through the inlet, the water forces the board away from the inlet when the outlet is enclosed such that the water may flow through the opening.

Abstract: A cam operated valve mechanism for directing the flow in a fluid flow duct to selective alternative outlets. The valve comprises an annular array of segmented elements which are each pivotally mounted to an axially translatable sleeve disposed coaxially within the duct. In a first axial position the sleeve extends across port and starboard alternative flow outlets, and in a second axial position extends downstream thereof. Each valve element comprises a cam follower which engages an axially extending cam track formed in the duct surface. The profile of the cam track is such that translation of the sleeve from its first to second axial position causes each of the valve elements to rotate from a stowed to a deployed position, and thereby obturate the duct.

Abstract: A constant air pressure unit for an air handling system. The unit comprises a housing having an air inlet opening for admitting pressurized air into the housing. The housing has a top wall with a by-pass opening therein and a door is displaceably retained over the by-pass opening. The door has a predetermined load whereby the door is caused to lift away from the by-pass opening when the pressure of the air in the housing is equal to the pressure required to lift the load. The door load defines a maximum housing pressure. In the case where the pressure at the inlet opening starts to increase above the predetermined maximum housing pressure, the door lifts and by-passes the excess pressurized air and thus limits the inlet and housing pressures. In a corollary unit, an air outlet opening for releasing air is included. A pressurized airflow path is defined between the inlet opening and the outlet opening.

Abstract: Underwater cleaning apparatus of a general type well-known includes a chamber having an inlet on one side thereof and a pair of outlets on the other side communicating with a pair of passages adapted for connection to a suction hose; a pair of valve seats for the outlets; a valve closure arrangement for the valve seats; a valve closure arrangement including a body, preferably of cylindrical segmental shape, mounted in the chamber to pivot about an axis perpendicular to the plane through the axis of the valve seats and including a closure for each seat with the closures disposed relative to each other and parallel to the pivotable axis such that the closures may close the valve seats alternately on oscillation of the valve body about its axis; and a curved surface connecting the closures with the surface being concavely profiled at least the areas adjacent the closures.

Abstract: A blade damper for use in fluid flow control devices having damper blades mounted on an axle and having extension ears mounted at opposite ends of the damper blades. The extension ears are mounted in a 90 degree relationship to the damper blades and are semi-circular at their boundary to allow for rotation with the damper blades. The extension ears prevent fluid leakage through boundary planes perpendicular to the axle when the damper is open thereby providing near linear side blade opening versus fluid flow characteristics.

Abstract: A diverter valve (10) provided at a three-way junction through which passes a high temperature gas, the valve having a closure member (12, 13, 14) pivotable between a first position in which it closes a first outlet branch of the junction and a second position in which it closes a second outlet branch of the junction, wherein the closure member carries one or more deflecting vanes (16) positioned (a) in front of the closure member so as to direct the flow of gas into and through the first outlet branch when the closure member closes the second outlet branch and (b) to be hidden behind the closure member and to be isolated from contact with the gas flowing into and through the second outlet branch when the closure member closes the first outlet branch.

Abstract: The invention relates to a discharge system for combustion gases of a gas turbine or the like, whereby one end of a discharge pipe is connected to the gas turbine or the like. The other end of the discharge pipe is connected to a heat exchanger. A branch pipe, which extends transversely to the discharge pipe, is connected to the discharge pipe. A valve mechanism is adjustable between a first position, in which the end of the branch pipe connecting to the discharge pipe is closed, and a second position, in which the discharge pipe is closed downstream of the connection of the branch pipe to the discharge pipe. The passage of the branch pipe is larger than that of the discharge pipe.

Abstract: A flow control valve includes a body having a hollow central section into which a flow control body fits. Three fluid flow ports are defined in the central section in a Y-shaped configuration to include a trunk port and two branch ports, and two flow ports are defined in the flow control body. The flow control body is moved from one orientation fluidically connecting one fluid port to one of the branch ports and the second port to the trunk port and a second orientation fluidically connecting the one fluid port to the trunk port and the second fluid port to the other one of the branch ports. Another form of the flow control valve includes a keystone shaped flow control body. The flow control valve can be used in a fluid circuit connecting a fluid source to various ones of a plurality of fluid flow driven subsystems.

Abstract: An improved gas flow diverter is provided, which includes a rotatably mounted diverter blade, a rotatably mounted turning vane assembly, a drive shaft adapted for receiving torque from a drive mechanism, and a toggle assembly, including a pair of toggle joints, mounted on the drive shaft and linked to the diverter blade and turning vane assembly. The improved construction of the gas flow diverter allows dependent synchronous rotation of the diverter blade and turning vane assembly.

Abstract: A delivery conduit operative through a valve member directs fluid selectively from the shower conduit to a storage tank in operative communication with a commode, wherein the storage tank permits selective use of water from a primary conduit or from the delivery conduit for the utilization of water therefrom.

Abstract: The selective creation of tramlines is disclosed where the metered seed normally delivered through the outlet hose (18b) of the row planter unit (20b) corresponding to the desired location of the tramline is diverted by a butterfly valve (26) to one or both of the row planter units (20a, 20c) located adjacent to and on opposite sides of the row planter unit (20b). The butterfly valve (26) includes an inlet conduit (28) which intersects with first and second outlet conduits (30, 32) and a butterfly element (34) which is pivoted by a solenoid actuator (40) against the bias of a spring (36) to selectively block one of the outlet conduits (30, 32).

Abstract: An air distribution housing in an automotive air conditioning system includes spaced wall portions forming an air passage for flow of conditioned air into the passenger compartment of a motor vehicle; each of the wall portions having pins directed internally of the wall portions without forming openings therethrough and including distal ends thereon inserted into a tubular end portion of the valve member for pivotally supporting the valve member within the air passage without penetrating through the spaced wall portions so as to prevent air leakage and resultant noise from the air distribution housing. A method of assembly of the air distribution housing includes the steps of providing two separate housing parts with integrally formed pins on the inner surfaces thereof; providing a valve door with a pivot tube on one end thereof; vertically locating one end of the tube on one of the pins; thereafter joining the housing parts to locate the other pin in the other end of the pivot tube.

Abstract: A fountain attachment for a faucet, comprising a tubular body of rigid plastic material, a closure member of rigid plastic material hinged to the short rear wall of the tubular body and adapted to be pivoted to cover its inclined outlet end, a fountain spout formed in the long front wall of the tubular body with an inclined passage terminating at its upper end in an upwardly directed spout opening and terminating at its lower end within the tubular body, and a tubular insert of yieldable plastic material disposed inside the tubular body, with its top end disposed within the top end of the tubular body and spaced therefrom by an annular gap and adapted for frictional fit with a faucet, the tubular insert further having a mid section supported within the tubular body and a bottom end comprising a sealing flange extending beyond the bottom end of the tubular body, the sealing flange providing a seal with the closure member when the closure member is pivoted to cover the outlet end of the tubular body.

Abstract: Steam quality at both outlets of a T junction is maintained equal to that of the inlet by variably controlling the pipe cross sectional area according to the ratio of vapor flow rates through the respective outlet legs.

Abstract: A three-way valve (11) is formed from three identical casing parts (13), between which is inserted a one-piece sealing cage (15). The flap-like valve body has a closure face (31) displaced eccentrically with respect to the axis or spindle (20) and whose marginal areas cooperate with the webs (24) of the seal (15). The valve creates an almost unconstricted passage in all three deflection directions and has only narrow, clearly defined sealing areas and can be completely washed round in a cleaning position.

Abstract: An air flow control valve assembly for selectively directing air flow through the air chambers of a heating, ventilating and air conditioning (HVAC) module. The assembly includes a support arm rotatably secured at one end to a flat plane valve and defining a first rotation axis therewith, and a second end rotatably secured to the housing of the module and defining a second rotation axis which is parallel and spaced from the first axis. The valve is actuated to move through an arcuate path about the second axis to selectively position the valve in sealing contact with first and second ports for controlling air temperature in a passenger compartment of a vehicle.

Abstract: A dual blend door for a motor vehicle climate control system allows operation of the door within an air passage with lesser effort and thus may be operated by a smaller and more efficient mechanism. The dual blend door provides a main door within which is an opening covered by a smaller inner door. Both the main door and the inner door are coaxially mounted on the same pivot shaft and pivoting of the shaft first opens the inner door, relieving the air pressure exerted upon the main door. Continued pivoting of the pivot shaft beyond a predetermined angle engages drive means comprising cooperating elements of the inner door and main door to open the main door subsequent to the opening of the inner door. In broader applications, the invention constitutes a fluid passage door assembly for controlling the flow of fluid through a passage.

Abstract: An apparatus for separating foreign bodies from a stream of fiber material includes a vertical chute having an upper inlet and a lower outlet; a mechanism for introducing the fiber material into the chute inlet; and a detector positioned in the chute for emitting a sensor signal upon passage of a foreign body. The fiber material is propelled from the detector towards the chute outlet substantially solely by gravity. The apparatus further has a waste discharge opening provided in the chute between the detector and the chute outlet; a deflecting mechanism arranged in the chute and having first and second positions. In the first position the deflecting mechanism causes the stream of fiber material to proceed in the chute to and through the chute outlet and in the second position the deflecting mechanism causes the stream of fiber material to proceed through the waste discharge opening.

Abstract: A valve including a valve member having two different stable positions, and a valve operator for shifting the valve member between its two stable positions and holding the valve member in those positions. The valve operator includes a shuttle moveable between two extreme positions corresponding to the two stable positions, respectively, of the valve member. A first spring urges the shuttle toward one of its extreme positions and a second spring, stronger than the first spring, urges the shuttle toward the other of its extreme positions, these movements of the shuttle being transmitted to the valve member. A device, such as an electric solenoid, selectively renders the second spring ineffective with respect to the shuttle, so that when the second spring is ineffective the first spring causes the valve member to assume one of its stable positions, and when the second spring is not ineffective, the second spring causes the valve member to assume the other of its stable positions.

Abstract: The invention is directed to a fluid distribution valve including a housing having at least three ports and a flap member for selectively closing the ports. The flap member is mounted by at least two mounting means which provide for pivoting of the flap about two different predetermined axes. At least one of the mounting means can be selectively engaged and disengaged to provide for pivoting of the flap member about a selected one of the two different axes. In a preferred embodiment, the valve of the invention is employed in combination with an air conditioning and cool storage system for a vehicle, such as a truck.

Abstract: A valve having a valve body formed with a chamber with which a plurality of ports in the valve body communicate. At least one of the ports is adapted for connection to a source of pressurized fluid. A rocker valve member is pivotally mounted within the chamber and swings between two extreme positions in which it closes and opens at least one of the ports. A diaphragm within the chamber extends from the periphery of the rocker valve member and the margin of the diaphragm is secured in the valve body. All the ports in the valve body face one side of the diaphragm. An operator, for swinging the rocker valve member between its extreme positions, engages the rocker valve member on the side of the diaphragm opposite the side facing the ports, so that the diaphragm serves to isolate the ports from the operator.

Abstract: A grain chute valve providing an enclosed valve member which will avoid leakage of grain between the valve member and the walls of the valve. Either two-way or three-way valves can be produced using the enclosed valve member of the invention.

Abstract: Valves of the diverter and isolating types have their ports which are to be opened and closed surrounded by seats each of which is inclined inwardly towards the surrounded port. The hinged blades are surrounded by tips in support of seals of which there are two for each port to be closed. The seals are metallic and resiliently flexible and the seals of each pair are disposed to engage spaced apart, transverse zones of a seat when a blade is operatively positioned to close the surrounded port. As a diverter valve has two ports to be closed by opposite sides of its blade, there are two like but oppositely disposed pairs of seals, one pair for each port. With both types of valves, the seals of a blade are in substantially linear engagement with a seat when the blade is positioned to close the associated port and are in scraping engagement with the seat as the blade moves into and out of that position.

Abstract: Exhaust mechanisms are useful for directing exhaust gas flow from an inlet to either a truck dump body or a muffler means. A mechanism for a vehicle includes a valve body haivng a valving element pivotally mounted to a telescopically movable tube moveable to a first position upon movement of the dump body to a raised position to direct exhaust from the engine to the muffler. With the dump body in the lowered position, the valving element is in a second position to direct exhaust to the dummp body. The valving element interacts with an upper stop plate when the tube moves upward and interacts with a lower stop assembly when the tube moves downward.

Abstract: Valve means includes a first pipe which receives a signal fluid stream. The stream is separated into two substreams in accordance with a control signal. A second and third pipe are connected to the separating apparatus provides the substreams external to the valve.

Abstract: An agricultural irrigation system comprised of a plurality of unit pipes which constitute a water supply pipe line and another plurality of unit pipes which constitute a plurality water dispensing line each of whose respective pipe units are connected to respective center, valve/connectors which couple successive pipe units of the water supply pipe line.

Abstract: An automotive vehicle air conditioning system has an air distributor duct branching off into first and second outlet ducts for delivering air in different directions, respectively and an air flow control device disposed at a junction where the distributor duct branches off into the two outlet ducts. The air flow control device consists of first and second air flow control members disposed side by side for deflecting air flows passing into the first and second outlet ducts, respectively, either one of the first and second air flow control members being actuated to deflect a flow of air passing therethrough so as to deliver air into the one of the first and second outlet ducts in a high proportion relative to air delivered into the other.

Abstract: An isolator including a combined blade and flap arm assembly in which two opposed side members (22) of a blade frame (31) are extended (22a) to attach to an operating shaft (21) to act as the load-bearing members of the system, the frame being completed by two opposed side members (23) oriented parallel to the shaft. Preferably insulation (37) is provided on one side only of a blade plate (33) attached in a flexible manner to a cross-sectionally generally channel-shaped blade frame by being either welded or bolted to at least one strip (34 or 34a, 34b, or 41, 42) welded to the frame. The blade designed in accordance with the present invention will accept differential expansion due to operational conditions while retaining the lightest possible construction.

Abstract: A heating, ventilating and air conditioning system for vehicles incorporating a rotary air valve mounted in a housing for limited arcuate movement with respect to a pivot axis to adjust the amount of opening of two adjacent air flow windows to thereby control the routing and quantity of air flow through the heater core and a heater core bypass. The rotary valve is moved in a track radially spaced above peripheral edges in the housing defining the windows to eliminate frictional drag and wear of the sealing face of the air valve as well as the load on the motor or mechanical actuator. The valve is positioned at an infinitely variable number of positions for partial opening of the windows and a camming system is used to move the valve without drag into or from sealing positions with respect to the two windows.

Abstract: A variable volume terminal unit for an air handling system includes a duct having an air by-pass outlet in its top wall, and a deflector blade that can be moved between a "straight through" position in which the by-pass outlet is closed, and a position in which at least some of the air flowing through the duct is deflected through the by-pass outlet. The deflector blade is of an angled shape selected so that, in the deflecting position, the blade presents a substantially symmetrical surface to the incoming air, while in the straight-through position, the blade closes the by-pass outlet.

Abstract: An agricultural irrigation system comprised of a plurality of unit pipes which constitute a water supply pipe line and another plurality of unit pipes which constitute a water dispensing line each of whose respective pipe units are connected in series by one or more separate center, valve/connectors which couple successive pipe units of both the water supply pipe line and the water dispensing pipe line.

Abstract: A duct leading to a bypass and a duct leading to a heat exchanger are arranged at the output side of the gas turbine. The two ducts can be closed alternately by flaps. Pivotable guide plates are arranged in the branching area of the two ducts. The guide plates are pivoted by linkages connected to the flaps in the duct leading to the heat exchanger, so that, when the flaps in the bypass are open, the guide plates are inclined relative to the flow of combustion gases and deflect the flow into the duct leading to the bypass. When the flaps in the duct leading to the bypass are closed, the guide plates are pivoted to extend parallel to the flow of combustion gases. In this position, the guide plates do not provide any resistance to the flow of combustion gases to the heat exchanger.

Abstract: An air conditioning apparatus is provided with an exhaust feature for exhausting air from the living enclosure. The air conditioning apparatus includes an evaporator blower for moving air from the living enclosure through an evaporator coil and back to the living enclosure. The evaporator blower includes a blower housing which includes an air inlet and an air outlet, and an exhaust opening is provided in the blower housing. An exhaust door is pivotally mounted on the blower housing and is movable between a first position in which the exhaust door closes the exhaust opening in the blower housing and a second position in which the exhaust door closes the air outlet of the blower housing and the exhaust opening is opened. When the door is in the second position, air is exhausted from the living enclosure through the exhaust opening.

Abstract: The invention provides a fluid switching microelectrovalve in which the mobile member playing the role of closure member for one or other of the pipes (18,19) is a single membrane (23) with oriented deformation applied by a rocker (24) against one or other of the pipes to be closed, the rocker (24) being moved from one to the other of its two balance positions corresponding to the two closure positions of the membrane by a spool (3) sliding in the valve body (1) under the action of the core of an electromagnet.

Abstract: A pneumatic wave-generator for a wave pool, comprising a caisson divided into a plurality of wave-generating chambers, a ventilator space provided with a powered source of forced air, and a system of conduits coupled to an air-directional valve which is capable of effecting forced aspiration and expiration above the water surfaces in the wave-generating chambers. The air-directional valve efficiently and selectively directs air into and out of a chamber, as desired, provides a seal against the unwanted flow of air, has a reduced number of moving pieces, is mechanically efficient, and has limited wear points.

Abstract: A Y-shaped air diverter box is utilized to permit the replacement of a malfunctioning air filtration unit which is being utilized in a contaminated work site area. The Y-shaped air box is utilized in such a manner so as to permit the purging and cleaning of the air conduit which normally connects the air filtration unit to an air exhaust as well as providing a means for cleaning the exhaust side of the new air filtration unit which is being placed into service.

Abstract: A solids flow distribution apparatus is disclosed for use with two or more solid separation devices, such as shale shakers. The appartatus includes a plenum in communication with a source of flow of solids and liquid, such as from a drilling rig's mud system. The plenum includes lower outlets positioned adjacent inlet zones for each solid separation device. Valves are positioned across the lower outlets for regulating the quantity of solids and liquids that flow into the inlet zones of each solid separation device. A variable distribution apparatus is included within the plenum adjacent the flow inlet for regulating the proportion of solids directed towards each solid separation device.

Abstract: The functions of a diverter valve and a variable orifice valve are combined in a single valve including an elongated magnetic member that is pivoted at a first end with a portion of the second end being positioned between opposed restrictors, a coil assembly for producing a magnetic field for selectively pulling the magnetic member toward one of the restrictors, sealing the restrictor it is pulled against thereby enabling the diversion of fluid flow, for example, from one nozzle to another, and further including a ball screw and torque motor attached to the first end of the magnetic member for selective movement thereof fore and aft, with the second end of the magnetic member being tapered and positioned in cooperative relation with respect to an orifice in a fluid inlet member whereby the fore and aft movement of the magnetic member controls the size of the orifice and the amount of fluid flow.

Abstract: A gas flow diverter receives large volumes of hot gases from a gas turbine into a chamber in which is a pivotally mounted blade adapted to close either the outlet port to a heat recovery steam generator or the outlet port to the stack. Each port is surrounded by an open channel, the two side walls of each of which are provided with an exposed seal arranged one beyond the other. One or both surfaces of the blade is insulated, the insulated surface(s) being covered with steel cladding and the uncovered surface being a stainless steel membrane adapted to resist corrosion from the hot gases. The steel cladding is connected through insulation to the underlying structure in a manner permitting but confining the expansion of the cladding.

Abstract: The subject flow proportioner device has a pivoting target plate opposite an inlet and between a pair of axially aligned exit ports. Product is introduced through a flow shaping inlet and strikes a profiled target on the plate forming a cushion and diverting the subsequent product between the outlets.

Abstract: The oral hygiene device comprises a nozzle-holder connectable to a liquid source and a nozzle (1) removably attached to the nozzle-holder, the nozzle being intended for spraying either a multi-jet of liquid via a first duct or a single jet of liquid via a second duct. A two-way valve (5) makes it possible to direct the liquid towards one duct or the other and therefore the branching of the two liquid ducts are located in the nozzle itself. There is a restoring spring (27) which is such that the stable position of the device is for multi-jet spraying, while under the action of an external force exerted on the control member (6) of the valve the device assumes the single-jet position.

Abstract: A diverter valve includes a valve body formed with a pair of openings. Inlet ends of a pair of discharge tubes are respectively carried by and extend through these openings. An elongated elastomeric strp then may be wound about each tube extended end to form a gasket. This wound strip is held in place by a clamp. The valve further includes a movable member formed with an opening to carry an outlet end of an intake tube. The movable member is pivotally attached to the valve body by two spaced apart pairs of link bars. As connected, the pairs of link bars are positioned in a parallel relationship. Operatively attached to one end of the movable member is a piston rod of an air cylinder which in turn is attached to the valve body. During use the movable member may be selectively positioned by the air cylinder to align the outlet end of the intake tube end with either discharge tube inlet end.

Abstract: An arrangement for a climate control in passenger spaces of power vehicles comprises a passage for supplying an air stream, two other passages located downstream of the first-mentioned passage, a branching located between the first-mentioned passage and the further passages, a flap-like member located in the region of the branching and movable between two end positions in each of which it closes a respective one of the further passages, the flap-like member having an end which faces toward the first-mentioned passage and being provided at the end with an auxiliary blade which extends over an essential part of a length of the member.

Abstract: A gas flow diverter receives large volumes of hot gases from a gas turbine and has a blade adapted to close either the outlet port to a heat recovery steam generator or the outlet port to the stack. Each port is surrounded by an open channel the two side walls of which are each provided with a seal with both exposed, one beyond the other. The surfaces of the blade are stainless steel cladding and are connected through insulation to a reinforcement in a manner permitting but confining the expansion of the cladding. The frame has a border providing first and second ledges on each side which are spaced and positioned so that each may engage a different one of the two seals bordering an outlet port when closed thus establishing the channel as a closed passageway surrounding the closed port which may be sealed against leakage by discharging sealing air into it.

Abstract: A diverter valve for diverting the flow of hot gases has a valve door pivotable between two outlets, each of which is surrounded by a bellows seal having a sidewall of significant width for continuous with the valve door and defining with the door a seal of large area. The sidewall is flat and uninterrupted, and the bellows can be made in various shapes, including circular, rectangular with rounded corners, and rectangular with mitered corners.

Abstract: A diffuser unit for air conditioning systems includes an air supply duct having an air inlet and two air outlets, two dampers for adjusting the open area of the respective air outlets, and a linkage mechanism interconnecting the dampers and a drive unit. The dampers include arcuate end portions for contacting an inner wall of the duct and for preventing the generation of wind noise from air being supplied through the duck. The linkage mechanism is so constructed as to displace a selected one of the dampers while holding the other damper in its closed position.

Abstract: Disclosed is an electromagnetically actuatable three-way/two-position valve for alternatively connecting an outlet connection with a first or a second inlet connection. The valve includes a housing having a cavity which is sealed by means of a cap and within which a magnet winding and a displaceably arranged armature are provided which, upon excitation of the winding, actuates a valve closing body which is preloaded into an inoperative position by means of a return spring supported against the housing. A communication between the first inlet connection and the outlet connection exists in the inoperative position.

Abstract: A diverter valve has a "Y" shape with a single inlet and two branch passageways formed at a confluence region of the "Y". A double sealing member paddle is pivoted on a shaft and located at the confluence of the two branches. The branches each have a replacement tapered seal seat. Rotation of the shaft in one direction forces one sealing member of the paddle onto one seat for full 360.degree. contact with the seat. Rotation of the shaft in the other direction forces the other sealing member of the paddle onto the other seat. A continuous peripheral seal contact is made with the seat. The seals and seats are concentric with the branch passageways and easily machineable and replaceable. The arrangement provides for smooth flow through the valve.

Abstract: A diffuser is provided with three discharges. Two of the discharges are directed in one direction and, when installed, would be directed towards the outside wall of the conditioned space. The other discharge is directed in the opposite direction and would discharge into the interior of the conditioned space. Responsive to the temperature of the conditioned air being supplied, a thermally responsive actuator of shape memory alloy is in either one of two positions whereby either one of the two discharges in the one direction or the discharge in the opposite direction is blocked. This results in two discharges in one direction or one in each direction with the discharge area being the same in both instances.

Abstract: Method and apparatus for removing extraneous matters from cooling water used in a tubular heat exchanger such as a condensor is disclosed. When a pressure difference between the portions upstream and downstream of a filter element exceeds a predetermined threshold value set in advance in accordance with the flow rate of the cooling water, a blow-down operation is started to remove the extraneous matters scraped off of the outer peripheral surface of the filter element by a turning flow. The extraneous matters are removed at a rate of clogging of the filter element of 50%, irrespective of the flow rate of the cooling water. The clogging rate can be sensed accurately, and the blow-down operation is effected with necessary and sufficient frequency.