Abstract: A three-way valve assembly connected between the purified water delivery tube and the pressure tank of a reverse osmosis water purifier, which includes a casing having a three-way valve controlled by a rotary lever to open or close the passage way through the casing, and a meter fastened to the casing to measure the quantity of water in the pressure tank.

Abstract: An apparatus and method for reducing pulsation-induced errors in the secondary system of orifice meters or other differential pressure flow measuring devices. The apparatus of the present invention comprising means for reducing the distance between the flow meter and the differential pressure detector for reducing pulsation-induced errors as well as reducing errors caused by rectification and energy redistribution, and means for maintaining a constant cross section between the orifice meter or the like and the differential pressure detector for reducing the pulsation-induced errors and, particularly for reducing errors caused by rectification and energy redistribution.

Abstract: A system is provided for determining the presence, or absence of a component on the end of a vacuum pickup device. A monitor having a transparent body portion and plural air flow passageways is provided. An indicator is provided for each vacuum pickup device and contained within the air flow passageway intermediate a vacuum source and the vacuum pickup device. The position of the indicators within the flow passage is dependent upon the presence, or absence of a component on the end of the vacuum pickup device. With a component present on the pickup device, air flow through the passageway, due to the application of the vacuum source, is minimal and the indicator will be biased in a first direction. However, when a component is absent the pickup device, substantial air flow occurs through the passageway, thereby biasing the indicator in a second direction.

Abstract: A regulator for pneumatic system comprising a connecting bracket for connecting other air conditioning units to a regulator body. Because of this connecting bracket, the air conditioning units to be connected to each other can be modularized. The connecting bracket has, at its both ends, a pair of projection-like pawl sections which are engageable respectively with engaging sections formed respectively on outer peripheral surfaces of the other air conditioning units. Incorporated in the connecting bracket is a pressure gage for detecting secondary pneumatic pressure within the regulator body. The pressure gage comprises a pressure detecting section, a pressure display section, pressure setting section and an abnormality alarm section.

Abstract: Apparatus and method for detecting fluid leakage into an enclosed leakage chamber or space sealed by a fluid seal exposed to pressurized fluid from a flow line or pressure vessel. Upon leakage of fluid from the flow line or pressure vessel past the seal into the leakage chamber or space, the leaked fluid is communicated to a piston chamber in a fluid indicator device. Upon the reaching of a predetermined high fluid pressure, the piston is actuated for extending an indicator rod of the fluid indicator into a projected position for visual observation. For testing or inspection of the leaked fluid, a separate removable adaptor is provided for moving the piston to a fluid bypass position to permit removal of fluid from the piston chamber containing the leaked fluid, or to permit injection of an external fluid such as a sealant into the piston chamber and leakage chamber.

Abstract: The connection strip is for use with a dual-purpose hot water and central heating boiler. The strip comprises four modules made of molded hard plastic and assembled side-by-side by being mutually juxtaposed with tie bars passing through them, the modules being respectively associated with outgoing heating water, outgoing domestic hot water, incoming cold water, and returned heating water, each module including the corresponding stopcocks and ducts together with lengths of a short-circuit duct enabling the modules to co-operate to form a short-circuit on the heating circuit, suitable for feeding water to said heating circuits and for enabling leak tests to be performed when the boiler is not present.

Abstract: This invention relates to a shutoff mechanism, in particular in the form of a hinged safety-valve for large gas ducts, which contains a plate-shaped shutoff body which can be pressed against a seat on the housing. To guarantee a reliable and secure shutoff of large gas lines, the shutoff mechanism, together with an additional cover, forms a gas-tight chamber closed off from the two chambers of the gas line. The pressure in this chamber is monitored and is different from the pressures in the two chambers of the gas line.

Abstract: An ultra low pressure flow sensor consisting of a support gasket defining a flow way and having a thin, pliable membrane extending thereacross with right angle slits formed totally across the flow way portion. An electrical conductor strip is then bonded across each pair of opposing quadrants of the membrane in continuous connection to an electrical indicator circuit. The conductor strip across each pair of membranes is centrally notched to a preselected depth of cut thereby to adjust the flow pressure break strength.

Abstract: A screw-in throttle valve and pressure gauge assembly including a valve member and a selectively rotatable screw-in member operatively associated with the valve member for permitting selected positioning of the valve member with respect to a valve seat. The screw-in valve member supports a pressure gauge at a location outside the valve body and the valve member is formed with a capillary bore communicating between a first flow duct downstream of the valve seat and the pressure gauge so that when the screw-in member and valve member are selectively positionable for varying the gap between the valve seat and valve member the valve gauge is simultaneously moveable with the valve member and screw-in member for directly measuring the pressure at the first flow duct without alteration of the pressure gauge.

Abstract: A fluid switch for measuring throughput in a fluid line, the fluid switch having an electrical switch and an associated membrane subjected to the pressure of the fluid introduced into a working chamber of the fluid switch. The fluid pressure causes simultaneous opening of a fluid outlet of the fluid switch and of contacts of the electrical switch. Thereby, the number of openings and closings of the switch will be representative of the number of openings of the fluid outlet and the throughput of the fluid. The membrane carries a projection serving as a valve which cooperates with a valve seat on the fluid outlet and the valve is coupled through a tappet to the electrical switch to open the switch when the valve is lifted off the valve seat.

Abstract: A drive for a feed valve having an actuating line and a device for controlling the pressure in the actuating line. The device comprises three valves connected to one another to form a hydraulic auctioneering circuit. The drive is suitable for a comparatively high oil pressure, and the drive is provided with a test system which monitors the operativeness of the drive. The test system is pressurized by the device, and a pressure drop can be sensed in the test system by a sensor.

Abstract: A medical valve comprises a rotatable member having a fluid flow path formed by a passageway. Flow path indicia on a surface of the rotatable member follows a path along the surface which substantially replicates the fluid flow path of the passage so as to indicate the orientation of the fluid flow path.

Abstract: A pressure regulator is described including an integral indicator which signals the near depletion of gas in a compressed gas cylinder to which the regulator is connected. The indicator remains extended as long as an adequate supply of gas remains in the cylinder. Upon the near depletion of the gas, the indicator withdraws into the regulator body to warn of the near depletion of gas.

Abstract: A valve of the kind for controlling the flow of fluid from at least two alternative supplies in such a manner that reduction or cessation of one supply automatically causes the valve to switch to another of the alternative supplies comprises a cylinder having a piston slidable therein in a region between a first fluid inlet and a second fluid inlet. The piston has working surfaces of differential area such that equal pressure on both sides of the piston biases the piston to one end of the cylinder. The valve has a fluid outlet with a first fluid flow path from the first fluid inlet to the fluid outlet, and a second fluid flow path from the second fluid inlet to the fluid outlet and including an axial outlet bore. The second fluid flow path is closable by the piston and is opened up on axial movement of the piston towards the first fluid inlet which is caused when the supply of fluid from the first fluid inlet fails, is arrested or falls below a predetermined limit.

Abstract: A conversion kit is utilized in combination with an air tank for containing pressurized air to include a series of inner communicating fittings mounted to a primary distribution block for utilization of the container as a transportable source of pressurized air. A modification of the invention includes the kit structure in cooperation with a cage organization to afford protection to the pressurized container minimizing damage thereto.

Abstract: A safety device for gas welding has a cylindrical main body having a flow path for an inflammable gas. A cylindrical cover is mounted on the outer periphery of the main body in such a manner that it can reciprocate on the outer periphery. The main body is provided with a normal-flow indicating mark and a counter-flow indicating mark which are positioned in space-apart relation on the outer periphery of the main body. One of the counter-flow and normal-flow indicating marks is exposed and the remaining one is covered alternately, depending on whether the flow condition is counter-flow or normal-flow.

Abstract: A method is described in which the operative condition of the cooling sections of a slot die for making flat films of thermoplastic material, or of an annular die of a blow molding extruder for making tubular films from synthetic thermoplastics, is tested. The cooling sections are provided with lines for supplying and discharging cooling air and the lines for supplying cooling air are connected, as required, to a central cooling air feed line, which is under superatmospheric pressure, by solenoid valves controlled by an electronic computer. In one embodiment of the invention, a testing program is performed in which the cooling air feed line is disconnected by a shut-off valve from the branch lines leading to respective solenoid valves when the latter are closed.

Abstract: In accordance with an illustrative embodiment of the present invention, a restriction sub apparatus for use during well cementing operations includes a tubular body having upper and lower internal recesses, a restriction ring having a shoulder engaged with the upper recess, and depending, inwardly inclined fingers at its lower end, and a back-up rubber ring mounted in the lower recess that yieldably resists expansion of the fingers as the drive plate of a displacement plug passes downward therethrough to provide a positive surface indication in the form of a pressure change that the plug is located at a particular depth.

Abstract: The pressure reducer body includes oppositely disposed bores for mounting inlet and outlet connecting devices, and the outer end of another bore defining a high pressure chamber in which the regulating valve is mounted, is adapted to receive a connecting device for a high pressure manometer defining a rest for a spring of a regulating valve which includes an annular truncated lining in which is force fittingly engaged a connecting rod between the regulating valve and the piston bounding the low pressure chamber. Applications to various pressure reducer arrangements for industrial use.

Abstract: A leak detector for a valve controlling flow of fuel to a combustion chamber employs a fuel concentration sensor in a sensing chamber placed downstream from the valve seat. The valve has a downstream chamber which is in communication by diffusion through an orifice, with a source of pressurized air. By injecting air into the downstream chamber through this orifice after the valve has closed and then measuring with the sensor the fuel concentration within the sensing chamber, excessive fuel leakage by the valve can be detected.

Abstract: A pressure regulator includes a flexible diaphragm which sets-off a liquid chamber having an inlet and an outlet for respectively introducing liquid into and discharging liquid from the liquid chamber under the control of an associated valve through an actuator operated by the movement of the diaphragm. The valve is carried by a coupling which is connected to the housing inlet which, upon the uncoupling of the coupling, allows inspection and/or repair of an associated valve seat or the actuator through the pressure regulator inlet. The pressure regulator can be cleaned or flushed by a novel method which includes uncoupling the coupling from the liquid inlet and reversing the connection with an associated standpipe outlet and thereafter reopening the liquid inlet valve. Liquid enters the liquid chamber through the standpipe outlet and discharges the liquid chamber through the liquid outlet thereby flushing the liquid chamber in a thorough and effective manner.

Abstract: An automatic changeover manifold is described which permits an uninterrupted supply of fluid, for example, cryogenic liquified gas, from a source to a fluid delivery conduit. Liquid flow is controlled by solenoid-operated on-off valves which are switched from an open-condition to a closed-condition in response to a detected low pressure condition. When flow ceases in one feed line, the solenoid-operated valve in the other feed lines opens. The electrical circuit prevents both solenoid-operated valves from being open at the same time, provided an electric current is present in the circuit.

Abstract: A first nozzle is connected to a space to be protected from excess pressure. A valve member releaseably seals the first nozzle. A second nozzle is coupled to an adjustable vacuum source for applying a predetermined vacuum level to the valve member to create a force against the member to seal the first nozzle. Seals are between the first and second nozzles and the member which couple the nozzles when the member disengages from the seals. The member disengages from the seals when the force on the member imposed by gas in the space being protected exceeds the force on the member created by the difference between ambient atmospheric pressure and the vacuum source pressure.

Abstract: Apparatus is provided for controlling the pressure of gas in a plurality of dunnage bags. The apparatus employs an enclosure which houses a pressure regulator valve, linear air reset controller, pressure gauge, pneumatically activated electrical switch, and three-position valve for permitting quick filling of the dunnage bags from a high pressure inlet line. A low pressure line emerges from the enclosure and communicates with the bags. When the bags are at proper inflation, the electrical switch causes a green light to be illuminated. When the bags are inadequately inflated, the electrical switch causes a red light to be illuminated.

Abstract: A medical gas alarm system is provided which includes a sensor unit pneumatically connected to a medical gas supply line and a switch connected to a valve in the supply line for detecting the open condition of the valve. In the event either the sensor detects a high pressure or low pressure condition in the supply line or the switch is activated by closing of the valve, an alarm signal is received by an alarm module and an alarm is activated. The alarm may be visual, audible or both. During normal operations, the alarm module displays both a system on condition and a digital display indicating the pressure in the supply line.

Abstract: A warning device for use with tanks of compressed air which device will automatically generate an audible warning signal that can be heard under water or in other noxious gas or in oxygen-depleted environments when the air pressure in the tank reaches a predetermined low pressure level.

Abstract: A valve and an arrangement for testing and draining a fire suppression water sprinkler system includes a valve which has a valve member with first, second and third ports which are coplanar. The selective rotation of the valve member interrupts a flow of water through the valve and permits a flow at two different preselected flow rates.

Abstract: A flow-control type piezoelectric element valve simplifies calibration of the gas flow rate, permits stable control of the gas flow rate and facilitates to supply a gas at stable flow rate. A gap is produced between a valve seat and a sealing portion comprising a sheet arranged on the top of the valve seat and a piezoelectric element, by applying from a current installation element to the piezoelectric element. Then a gas is introduced into a gas channel within the valve seat through the gap, pressure of the gas flowing along the gas channel is detected by means of a pressure sensor mounted near the outlet of the gas channel. According to correlation between pressure and gas flow rate in the output characteristics on the pressure sensor, the flow rate at the time when a gas flows along the gas channel can be accurately and easily calculated.

Abstract: Method and apparatus for cleaning fuel injector systems of internal combustion engines which comprises avoidance of burns and possible injuries in setting up the conventional system apparatus in the engine compartment. The present method is characterized by setting up the required connections and apparatus at the rear of the vehicle in an area isolated from the region under the vehicle hood. The invention has other advantages. In particular, filter replacement in the isolated area subsequent to completion of the cleaning process is effected by a novel aspect of the method which involves filter removal as a step in the method. In a conventional method the filter is left in place but ultimately replaced, for comprehensive maintenance of the fuel system, as an additional step. Another advantage of the invention is the method of detecting leakage in injector and fuel flow systems and to detect the extent of clogging of individual injectors to determine the need for replacement.

Abstract: An add-on liquid overflow shut-off valve including a valve body, a float and an arm connecting the float to the body that is insertable in fully assembled form through a standard tank lid opening, and further including a flanged end on the valve body for engagement outside and above the rim of the opening and threads associated therewith to engage the periphery of the opening to anchor the body inside the interior of the tank and at the top thereof, pneumatic openings formed in the top flanged end in spaced-apart relation for connection respectively to a pressurized pneumatic source and a pneumatic-driven liquid pump arranged to pump liquid into the tank through another opening in the tank, first and second pneumatic passageways formed interior the body extending from the openings, a third pneumatic passageway formed in the body for interconnecting the first and second passageways, and a shaft pivotally received in the body, having a fourth pneumatic passageway formed therethrough for pneumatic alignment with

Abstract: A re-settable apparatus for producing a signal for triggering off a safety measure on an installation with at least a pneumatic feed in response to a drop in the pneumatic feed pressure comprises a body providing an internal chamber connected by a first duct to a first orifice for connection thereof to the pneumatic feed, by a second duct to at least one member for outputting a signal for control of the triggering effect, and by a third duct to an exhaust orifice. The first duct opens into the chamber through a first seat and the third duct opens into the chamber through a second seat of larger diameter than the first seat. A valve member is mounted in the chamber movably between a first position in which it is applied against the first seat and a second position in which it is applied against the second seat, while a resilient return member between the body and the valve member urges the valve member towards its first position with a force of given intensity.

Abstract: The invention is an electronic monitor for monitoring the pressure of in fluid circuitry and governing the shutdown in such mechanisms as dynamometers. The monitor has two pressure switches at every point in the fluid circuitry where pressure is sampled, and has a monitor circuit responding to signals from the switches to selectively energize lights indicating the status of the fluid circuitry. The monitor has a circuit for shutting down the dynamometers and other equipment when pressure falls below a predetermined threshold at one of the pressure monitoring points. The monitor also has a circuit for detecting which of the points is first to experience a fall in pressure below the threshold when the fluid circuitry as a whole is losing pressure.

Abstract: An alarm valve and a backflow preventer are provided by a check valve and an alarm valve with a passageway provided between the check valve and the alarm valve preferably having a relief valve which selectively drains the passageway in response to the pressure in the main conduit upstream of the check valve. An alarm is sounded when the alarm valve is open. An impeller flow sensor may be provided in the backflow prevention device.

Abstract: A coupling for a pressure or vacuum fluid system having a bowl and filter head (10, 26) that connect together by relative rotation to engage bayonet coupling formations (32, 34, 94) thereof. When connected together the bowl (10) and filter head (26) have outer walls (16, 104) overlapping with an intervening seal (22) therebetween. A pressure relief valve (38) is provided in one of the members (10). A latch (36, 108) engages at an angular position of said members (10, 26) where the bayonet coupling is established to prevent relative rotation of said members (10, 26) and is prevented from engagement at other angular positions. The latch (36) is decoupled from the valve (38) when in its engaged state but is operatively coupled to the valve (38) when in a disengaged state to open said valve (38), fluid flow therethrough providing an audible warning when a pressure differental exists across the valve (38).

Abstract: A rupturable fluid flow indicator and a rupture disk assembly including the indicator are provided. The indicator is comprised of a rupturable member adapted to be clamped across a fluid flow passageway having at least one opening formed therein for weakening a portion of the member. An electric current conductor adapted to be electrically connected in an alarm circuit is attached across the weakened portion of the rupturable member whereby when the member ruptures as a result of fluid pressure exerted thereon, the conductor also ruptures.

Abstract: A valve includes a housing having an inlet, an outlet, and a passageway that connects the inlet and the outlet in fluid communication. A valve member on the housing for opens and closes the passageway and an actuator on the housing that is responsive to movement such as may accompany an earthquake causes the valve member to close the passageway automatically in the event of such movement. The actuator may include a spring for driving the valve member from an open position to a closed position, and a trigger mechanism responsive to movement such as may accompany an earthquake for holding the valve member in the open position until the occurrence of such movement and then enabling the valve member to move to the closed position under influence of the driving means.

Abstract: A flow control and pressure reducing valve has a valve body with an inlet chamber and outlet chamber separated by a partition plate. A plurality of passages are formed in the valve body spaced circumferentially around the partition plate and have an inlet portion opening into the inlet chamber and an outlet portion opening into the outlet chamber. Elastomeric flow control means are positioned in the passages and are responsive to pressurized fluid introduced therein to control flow of fluid through the passages around the partition plate. The valve configuration allows the mounting of inlet and outlet gates within the inlet and outlet chambers to eliminate the need for separate gate valves. An auxiliary flow passage may be provided through the partition plate and flow controlled therethrough to increase the flow capacity of the valve yet still provide full flow and pressure control. Air inlet and relief valves may also be provided as an integral part of the valve.

Abstract: This invention relates to a pneumatic valve assembly for controlling a compressed air stream in response to a non-contacting actuation. It is desired to provide such a valve assembly which is adapted to control high working pressures without an intermediate amplifier. This is accomplished in that a pivoted one-armed or double-armed lever is provided with a permanent magnet on one side or on each of both sides of its pivotal axis and via a ferromagnetic or magnetic actuating member which is moved into the proximity of the permanent magnet or magnets and via a plunger causes a pilot orifice to be opened or closed, which orifice is adapted to be flown through by a pilot air stream for actuating a pilot piston for moving a valve piston to positions in which the valve is opened or closed.

Abstract: An arrangement for treating hair with a liquid in a circulating process, comprises a circulating pump, an electric motor arranged to drive the circulating pump, a treatment time determining device, at least one treatment start switch arranged to control the treatment time determining device, the treatment time determing device being connected with the electric motor so that the electric motor is turned off at a treatment end, and a sensing element arranged to sense a parameter of a treatment liquid and operative so that the treatment time determining device is controlled through the sensing element in dependence upon the parameter of the treatment liquid which no longer substantially changes.

Abstract: The present invention provides apparatus for visually indicating the failure of a rupture disc comprised of an elongated hollow body member, a piston disposed in the body member which is moved therein by pressurized fluid pressure exerted thereon, and an elongated indicator pin which is pushed by the piston through an opening in the body when pressurized fluid causes the piston to be moved therein. The body member includes a pressurized fluid exhaust port which is opened by the movement of the piston. Pressurized fluid exhausted through the exhaust port can be vented to prevent abnormal rupture disk operation or it can be utilized to activate an alarm.

Abstract: This invention discloses a truck with a hand-operatable bed of which the front side under surface is provided with a pair of front wheels and of which the rear side under surface is supported by a hydraulic cylinder, for lifting or lowering the bed, mounted on a pair of rear wheels by means of bearings, which is characterized by being further provided with an overload-sensing device and an alarm-raising device to be put into operation according to the sensing of the overload-sensing device. Because operators can be told about an overload immediately by the devices, they do not have to keep a plunge pump working without being aware of an overload applied on the cylinder as did before. What is more, as they can realize whether the cause of not feeding oil to the cylinder has come from troubles in pressure lines or an overload, they can take measures against the cause at their earliest possible, with the result that the safety and the operatability in handling the truck are improved greatly.

Abstract: Vacuum regulator apparatus comprising: a valve that in use is arranged to admit air to a vacuum system that in operation is at a sub-atmospheric pressure, the apparatus being so arranged that an increase in the pressure in the vacuum system tends to cause less air to be admitted to the vacuum system by the regulator apparatus, and vice versa; means responsive to the position of the said valve arranged to give a first signal if air is being admitted at more than a first predetermined rate and a second signal if air is being admitted at less than a second predetermined rate lower than the first; and pressure-responsive means arranged to give a third signal if the pressure in the vacuum system is outside a predetermined range.

Abstract: An emergency gas flow shutoff device for use primarily with gas cylinder operations. When there is a sudden loss of resistance downstream of the device due to a cut hose or a fire from a severed hose a ball located in the device completely closes off an orifice to stop further gas flow. The device also incorporates a gas flowmeter or pressure gauge as part of the reset mechanism thus eliminating additional connectors.

Abstract: A system for controlling the amount of torque applied by a hand-held power tool to fasteners during an assembly of parts. In the preferred embodiment, a torque control circuit is operated by air to deliver a selected volume of air under selected pressure to the tool and to stop the delivery of air when the desired torque has been applied to the fastener. The system can operate one or more torque control circuits. Visual color coded signals can be used to indicate the active circuit and the tools intended to be used with that circuit.

Abstract: A sprinkler head having a readily accessible top plug which can be removed and replaced by a pressure-reading gauge that is in fluid communication with the head's interior pressure. Each individual sprinkler head includes a manually-adjustable pressure adjusting screw which is accessible at an exposed location for the installed sprinkler head. Pressure adjustment for an individual head, while it is operating in either a manual or an automatic mode, is available. After individual pressure adjustment for a sprinkler head has been performed the gauge is removed and the plug is replaced for normal sprinkler operation.

Abstract: In accordance with illustrative embodiments of the present invention, restriction subs for use in setting cement plugs in wells include a tubular threaded adapter having an internal annular recess, and a metal restriction sleeve mount in such recess. In one embodiment, the sleeve has a corrugation that extends into the bore of the adapter to provide a deformable restriction; in another embodiment the sleeve has curved resilient tabs whose free ends extend into such bore. The restrictions are cooperable with a displacement plug having a metal expander member on its nose so that a distinct pressure is required to cause the expander member and plug to be forced through the restriction.

Abstract: A pressure gauge has a turning button, a turning disc and a sliding block disposed thereon that, through a protruding wheel fixed on the needle shaft moves the sliding block to force a contact point of a conducting metal piece to contact with a contact point of the turning disc, can start an alarm in case the needle of the gauge comes to reach the designated pressure.

Abstract: A drilling fluid saver valve apparatus incorporating a pressure test device. The apparatus includes a tubular body having a valve seat and a closure check valve moveably mounted in spring loaded relation within the body to be normally seated in closed relation to permit flow of fluids under pressure only from a drilling kelly into the drillpipe, and a pressure test device connected into a side port formed in the body between the valve seat and drillpipe.

Abstract: A pressure regulator has a first and a second chamber which are separated by a movable piston varying the size of the chambers and which are in fluid contact with one another through a channel extending in the movable piston. The piston has a greater pressure surface area in the first chamber than in the second chamber. A high-pressure chamber beneath the bottom of the second chamber, has an aperture disposed in the bottom of the second chamber. A valve seat is disposed in the second chamber and cooperates with the movable piston to form a throttle between the high-pressure chamber and the second chamber. A high-pressure piston disposed in the high-pressure chamber projects into the second chamber through the first aperture and is displaceable in its longitudinal direction therethrough. A second aperture is provided at the end of the high-pressure piston which faces the second chamber. Also, a channel in the high-pressure piston extends from the second aperture throughout the entire high-pressure piston.

Abstract: A valve for checking tire pressure comprising a hollow cylinder, a sealing block, a plate, a spring and a flute. The hollow cylinder has a flange inwardly extending at intermediate portion thereof to form an opening and divide the hollow cylinder into upper and lower portions. The sealing block is disposed in the lower portion of the hollow cylinder and contacts with the flange to seal the opening. The sealing block is provided with a passage communicating both sides of the sealing block. The plate has a pin downwardly extending into the opening and contacting the sealing block and a seat formed on upper surface of the plate. The spring is disposed on the seat of the plate. The flute mounted on the hollow cylinder includes a base and a flute body disposed on the base. A passage is formed in the base which communicates the flute body with the upper portion of the cylinder.