US2071789A - Exhauster for sprinkler systems - Google Patents

Description

Feb. 23, 1937.

-W. B. GRIFFITH ET AL EXHAUSTER FOR SPRINKLER SYSTEMS Filed May 14, 1935 2 Sheets-Sheet 1 Feb. 2 3, 1937.

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W. B. GRIFFITH ET AL EXHAUSTER FOR SPRINKLER SYSTEMS Filed May 14, 1955 R 2 Sheets-Sheet 2 frwerztvm;

Patented Feb. 23, 1937 amuse- 2,071,789 EXHAUSTER FORSPRINKLER; SYSTEMS William B. Griffith, Audubon, N. 3., and David Arthur Keller, Drexel Hill, Pa.

Application May 14, 1935, Serial N0. 21,364

13 Claims. (Cl. 169-17) Our invention relates to improvements in dry pipe sprinkler fire extinguishing systems containing air under pressure for holding the dry pipe valve closed against water under a supply pressure. The invention particularly relates to systems including apparatus for rapidly exhausting the air pressure and for accelerating the opening of the dry pipe valve upon the opening of a sprinkler head.

Exhausters and accelerators now in general use employ a retaining chamber in communication with air under the system pressure, by means of a restricted orifice, of pin point dimension, through which theair pressure slowly equalizes due to leakage, and when a sudden reduction in the system pressure occurs, due to the opening of a sprinkler head, said restricted orifice retards the reduction of the pressure within said chamber and the retarded pressure is utilized toopen an exhaust valve through which the system pressure is further reduced. Such devices have failed to operate due to the clogging of the orifice by the accumulation of foreign particles.

The object of our invention is to provide means for insuring the proper operation of the retaining chamber by eliminating the possibility of failure of operation due to the restricted orifice being obstructed.

A further object is to construct a retaining chamber with a connection containing a body of liquid which is movable therein for imparting the system pressure to air confined in the retaining chamber, and to actuate the exhaust valve by means movable by the expansive action of the pressure retained in said chamber by the inertia of the liquid, when there is a sudden reduction in the system pressure.

A further object is to provide a retaining chamber having a member movable by air confined under pressure Within said chamber and provide a connection between said chamber and the system containing air under pressure, said connection containing a liquid for excluding said air from the connection below the level of the liquid, and for maintaining the connection free from foreign matter tending to clog the connection.

A further object is to provide said connection for containing the liquid with a sleeve formed of material impervious to corrosion due to the liquid,

said sleeve forming a'restricted orifice for the passage of liquid through the connection.

A further object is to associate a reservoir with the connection containing the liquid, in which reservoir the surface of the liquid is exposed to the air under the system pressure.

A further object is to provide actuating means of novel form between the movable member and the exhaust valve for opening said valve.

A further object is to provide a casing forming a pressure chamber and an inlet chamber, said drain valve, together with novel means for actuating said valves.

These together with various other novel features of construction and arrangement of the parts, which will be more fully hereinafter de scribed and claimed, constitute our invention. Referring to the accompanying drawings: Fig. 1 is a vertical sectional view of our improved exhauster, as on line I--l Fig. 2, and showing, diagrammatically the exhauster connected with a dry pipe system, in dot and dash lines.

Fig. 2 is a horizontal section on line 2--2 Fig. 1. Fig. 3 is a vertical section on line 3-3 Fig. 1. Fig. 4 is a perspective view of the pivoted mem-' her for actuating the exhaust valve, detached.

Fig. 5 is a perspective view of the exhaust valve clapper, detached.

In the accompanying drawings in which like 1 reference characters refer to like parts, 8 represents a combination accelerator and exhauster embodying our invention. A casing IE3, comprises sections l2, l3 and I4, which sections are secured the sec- 26. The dry pipe valve may be of any well known type having an air clapper 21, a water clapper 28 and an intermediate, or neutral air formed between the clappers. The clappers are chamber 29,

held closed against the water pressure in the pipe 26 by air under the system pressure contained in the riser 22 and the branch matic sprinkler heads 30.

The section M of the casing H3 is provided with a drain aperture 32 for the connection of a drain pipe 33. A valve seat 35 is provided pipes having autoupon the section l4, and said seat surrounds the drain aperture 32. A drain valve 35 is normally held closed upon the seat 34 by a spring 36, in-

terposed between the valve and a bearing 31 supported by arms 38 from the walls of the section I4.

The drain valve 35 is secured upon a shaft 39, movably mounted in said bearing 31. The upper end of the shaft is secured by means of clamp plates 40 and 4| to the diaphragm l8. The shaft 39 is provided with a small passageway 43 through which air under the pressure of the system may slowly equalize on opposite sides of the diaphragm l8, thus permitting the spring to normally hold the drain valve 35 closed upon its seat. When the pressure is exhausted from the pressure chamber 45, as more fully hereinafter described, the system pressure in the inlet pressure chamber 46 will move the diaphragm I 8 and lift the drain valve 35 against the action of the spring 36 and open the drain valve .35, thus allowing the air under the system pressure to rapidly exhaust through the drain pipe 33.

The novel features of the present invention include a retaining chamber 48, comprising a receptacle 50 located within the pressure chamber 45, formed within the casing sections l2 and I3. The section I3 is provided with inwardly projecting lugs 52, 53 and 54, shown in Figs. 2 and 3. The receptacle 5!] is provided with outwardly projecting lugs 55, 56 and 51, which are supported upon the lugs 52 to 54, of section l3, by means of fastening devices 58.

The lug 52 is of hollow construction and forms an exhaustpassage 60 and also a connection for a pipe 61, arranged to communicate with the intermediate chamber 29 of the dry pipe valve. The lug 55 on thereceptacle 58 has an aperture 62,-which registers with the exhaust passage 60 formed through the lug 52. A gasket 63 forms an air tight joint between the facing surfaces of saidlugs.

The exhaust passage formed through the lugs 52 and 551s normally closed by an exhaust valve 64, comprising a tubular fitting 65, secured in the aperture 62 in the lug 55. Said fitting 65 is provided with a valve seat 66 for a clapper 61. Said clapper has two arms 58 which are pivotally mounted upon a shaft 69 and which in turn is mounted upon a bearing 10 formed upon the wall of the receptacle 50. The clapper 81 is provided with a resilient gasket H for tightly sealing the outlet through the valve seat 66 when the clapper is held in the closed position upon its seat by air under the system pressure within thechamber 45. The clapper 61 is opened in a manner hereinafter described;

The receptacle 50 forms a retaining chamber 48, said chamber is sealed by a movable member 13, which separates the retaining chamber from the pressure chamber 45. The movable member I3 is in the form of a diaphragm having its periphery secured upon the receptacle 50 by a clamp ring 14, secured to the receptacle by fastening devices 15.

A reservoir 18 is located within the pressure chamber 45 and is in communication with the retaining chamber 48 through a passageway 19, formed within a connection 8!], and through an aperture 8| formed through a tube 82 secured in the bottom wall 83 of the receptacle 56, by a packing gland 84.

The connection 88 is secured upon the under facingsurface of the receptacle 5!! by fastening devices 85. The reservoir 18 is entirely supported by the-connection 80. A body of liquid 86, preferably mercury, is contained in the passageway "19 of the' connection 86 and occupies the lower portion of the reservoir 18 and. the retaining chamber 48 and forms a seal for preventing the passage of air to and from the retaining chamber 48.

The surface of the liquid 86 in the reservoir 18 is subjected to the air under the system pressure and contained in the pressure chamber 45. The upper surface of the movable member 13 is also subjected to the air under the system pressure and contained in the pressure chamber '45. The system pressure upon the liquid inthe reservoir 18 causes the body of liquid to compress the air entrapped in the retaining chamber 48, between the surface of the liquid in said chamber and the innersurface of the movable member 13, so that thepressure on opposite surfaces of the member 73 will slowly equalize by the liquid being forced to. and from the retaining chamber 48, due to slow variations in the system pressure due to leakage.

The exhaust valve 64 is provided for controlling the flow of air from the chamber 45 under the system pressure. Said valve 64 is preferably located within the pressure chamber 45.

Mechanism is provided for opening the exhaust valve 64 by moving the clapper 6! from its seat by a movement of the diaphragm, or movable member 13, when the latter is acted upon by a preponderance of pressure in the retaining chamber 48, upon the occurrence of a sudden reduction of the system pressure due to the opening of a sprinkler head 30.

The reduction of the pressure in the pressure chamber 45 relieves the pressure from the upper surface of the movable member 13, so that the expansive force of the .air retained by the liquid within the chamber 48 will move the member 13 and actuate the mechanism for opening the exhaust valve 64.

The air pressure is retained in the chamber 48 for a relatively long period of time after a reduction occurs in the system pressure, due to the inertia of the liquid 86. The liquid flows slowly through the connection from the retaining chamber towards the reservoir I8 when the air pressure in the reservoir 18 is reduced. by a reduction of the system pressure.

Any liquid such as water, oil, or mercury, may be employed for filling the passageway formed through the connection 80, between the retaining chamber 48 and the reservoir 18.

The reservoir 78, retaining chamber 43 and the connection 80 are constructed of such capacity that they will contain sufiicient liquid to insure the passageway and the tube 82 being submerged in the liquid at all times and under all variations of pressure, thus avoiding the clogging of the passageway 19 and the aperture 8| by the accumulation of foreign particles which would otherwise be carried by the air if it came in contact with the passageway and the aperture 8!. By thus always maintaining liquid in the passageway we eliminate the trouble heretofore experienced in devices having a restricted aperture for the passage of air between a retaining chamber and the system pressure.

The reservoir 18 and the retaining receptacle 58 are positioned in spaced relation and the connection 88 is connected between and below the bottom portions thereof, thus a structure of U-tube formation is provided for containing the liquid 86.

The passageway between the reservoir 18 and the retaining chamber 48 must always be kept open and free fromcorrosion and therefore we employ a tube 82 which is formed of glass or porcelain for this purpose.

The tube 82 forms the restricted portion of the passageway between the reservoir and the retaining chamber 48. The size of the aperture 8i through the tube depends uponthe viscosity of the-liquid employed. The greater the viscosity of the liquid the greater will be the diameter of the aperture required through the tube. However the use of a liquid instead of air permits the employment of a relatively larger restricted orifice or aperture than the minute aperture, of pin point dimension, heretofore used in exhausters and accelerators for retaining the air under pressure in the retaining chamberafter the occurrence of a reduction in the system pressure.

Mercury has been found to be the most suitable liquid for carrying out our invention as it will remain fluid at theordinary temperatures to which sprinkler systems are subjected. 'A further advantage in the use of mercuryisthat all foreign particles will, float upon the surface and will not be carried through the passageway leading to the retainingchamber.

The novel mechanism for opening the exhaust valve 64 by the action of the movable member 13, comprises, a latch lever 88, pivoted upon a pivot pin 89, mounted upon bearings 90 and 9!, formed on arms 93 and 94 and forming part of the clamp ring it. The opposite end of the lever 88 is pivotally connected by apin 93 with a head 94 which is supported upon, or positioned adjacentto'the movable member 13.

A rotatable member 96 is on the shaft 69, on which the clapper 61 is pivoted. Said member 96 has a body portion 91 having two arms 98 and 99 whichembrace the bearing 10 and also embrace the arms 66 formed on the clapper 61, whereby the clapper and the member 96 are rotatably mounted upon the shaft 66 and movable independently of each other. The member 96 is provided with an arm I66, to which one end of a spring I6! is attached. The opposite end of the spring is attached to a post I92, forming part of, or mounted upon the clamp ring M.

The rotatable member 96 is provided with a segmental web 165, the upper portion of which forms a tooth Hi6 which normally engages a shoulder I61 upon the lever 88, whereby the lever acts as a trigger for holding the member 96 against the action of the spring lfll. When the lever 88 is lifted by the upward movement of the member, or diaphragm 13, the tooth i96 will be released from the shoulder NH, of the lever 38, and the spring will rotate the member 96'about its pivot pin 69.

The body portion 9'! of the member 96, as shown in Fig. 4, has two depending side bars I69 and H9, connected by a cross bar H2, and forming a loop which loosely embraces a tongue H3, formed upon the clapper 61. The tongue I I3 projects into said loop and is normally positioned in spaced relation with body portion 9'5 and the cross bar H2, so that the clapper 61 can be moved by the action of air under pressure within the chamber 45, independently of the member 96, and thus compress the gasket H, carried by'the clapper, against the valve seat 66. By this arrangement the clapper is normally held tightly closed upon the valve seat.

Another advantage of the enlarged loop upon the rotatable member 96 is that when the latter is released from the lever 88 and is rotated by pivotally mounted the spring IUL'said member 96 will have gained some momentum bythe time the cross bar H2 takes against the tongue H3 of the clapper, whereby. the impact of the cross bar against the clapper will assist the action of the spring to open the clapper against any pressure remaining in the pressure chamber 95 and also to overcome any tendency of the clapper to stick I upon its seat.

The upper section it: of the casing is provided with a removable plug H6, asshown in Fig. 2, which plug may be removed for making the exhaust valve 5 3 and the rotatable member 96 accessible, so that after the device has operated to exhaust the air from the sprinkler system, the rotatable member 96may be reset in engagement with the latch lever 88, thus allowing the exhaust valve clapper 57 to close upon its seat.

The reservoir 18 has a cap i it, provided with a threaded aperture l H, for the insertion of a plug, not shown in the drawings, to retain the liquid in the reservoir during shipment. The plug may be removed from the cap ll6 through the opening formed in the casing and occupied by the larger plug l i5.

By removing the fastening devices 56 the top section l2 may be removed, thus making the receptacle 5B and the reservoir 18, and also the exhaust valve 66, accessible. By removing the fastening devices 58, shown in Figs. 2 and 3, the receptacle 5!], reservoir 18, and the exhaust valve 66 may be removed as a unit.

The operation of the invention is as follows: The air under the system pressure tends to keep the drain valve and the exhaust valve 64 closed, also the clappers 21 and 28 of the dry pipe valve closed. The air under the system pressure passes through the passageway 63 and equalizes the pressure in the chambers 46 and 46, on opposite sides of the diaphragm i6, during slow changes in the pressure due to leakage.

The reservoir 18 is open to receive air under pressure through the aperture H1, equal to the pressure in the chamber 45 and this same pressure acts upon the upper side of the movable member 13, which seals the chamber. The air under the system pressure acts upon the surface of the liquid 86 within the reservoir 18, and the liquid is moved through the connection 80, so that the body of liquid within the retaining chamber 56 compresses the air within the chamber 48"against the under surface of the movable member 13, so that the latter will remain balanced between equal pressures on opposite sides of the member 13, and slow changes in the system pressure will be compensated for by the movement of the liquid through the connection 6 3.

A sudden reduction of the system pressure, by the opening of a sprinkler head, reduces the pressure in the chambers 45 and #36 The reduction of the pressure in the chamber 45 causes a reduction of the pressure upon the upper side of the movable member 13, the exhaust valve clapper 61 and also upon the surface of the liquid in the reservoir '18. The air under pressure will be retained within the retaining chamber 48 by the retarded flowing of the liquid through the tube 82, from the chamber 48 toward the reservoir 18.

The relatively higher pressure retained in the chamber 48 will move the diaphragm or member '53 upwardly against the reduced pressure in the chamber 65. The upward movement of the member I3 will lift the latch lever 88 and withdraw the shoulder lil'! from the tooth I66 of the rotatable member 96. The spring It]! will then rotate the member 96 about the shaft 69 and the cross bar H2 will engage the clapper 61 and lift it from its seat and open the exhaust valve 64. The air under the system pressure will pass through the exhaust valve and the connection Bl to the intermediate chamber 29 of the dry pipe valve and accelerate the opening of the clappers 21 and 28.

When the air pressure is exhausted from the pressure chamber 45, by the opening of the exhaust valve 64, the system pressure still remaining in the inlet chamber 46 will act upon the under surface of the diaphragm 18, due to the small restricted passageway 43, and cause the diaphragm I8 to lift the drain valve 35 from its seat, thus allowing all the air under the system pressure to rapidly exhaust through the drain valve 35. When the pressure again equalizes on opposite sides of the diaphragm l8, the drain valve 35 will be closed by the action of the spring 36, thus preventing the flow of water into the drain pipe 33, when the air is replaced by water throughout the system by the opening of the dry pipe valve.

Various changes may be made in the construction of the parts and the operation thereof without departing from our invention.

We claim:

1. An exhauster for a dry pipe sprinkler system comprising a pressure chamber adapted to contain air under the system pressure, a sealed expansible air retaining chamber located in said pressure chamber and subjected externally to the pressure in said pressure chamber, a connection having one end connected with said retaining chamber and its opposite end subjected to the pressure in said pressure chamber, a body of liquid in said connection and arranged for compressing the air in said retaining chamber relatively to the pressure in said pressure chamber acting upon the liquid, said connection having a contracted portion for retarding the fiow of the liquid, a valve controlling the flow of air from the pressure chamber, and valve actuating means operatively associated with said retaining chamber and arranged for opening the valve by the expansion of the retaining chamber caused by the expansive action of the air retained in the retaining chamber by the inertia of the liquid upon the occurrence of a sudden reduction in the pressure in said pressure chamber.

2. An exhauster for a dry pipe sprinkler system comprising a pressure chamber adapted to contain air under the system pressure, a sealed expansible air retaining chamber located in said pressure chamber and subjected externally to the pressure in said pressure chamber, a U-tube having one end connected with the retaining chamber and its opposite end subjected to the pressure in said pressure chamber, a body of liquid in the U-tube arranged for compressing the air within the retaining chamber relatively to the pressure in said pressure chamber, said U-tube having a reduced portion for retarding the flow of the liquid and for retaining the air under pressure within the retaining chamber upon the sudden reduction of the pressure in said pressure chamber, a valve controlling the flow of air from the pressure chamber, and mechanism operatively associated with the retaining chamber and the valve for opening the latter by theexpansion of the retaining chamber.

3. An exhauster for a dry pipe sprinkler system comprising a pressure chamber adapted to contain air under the system pressure, a sealed expansible air retaining chamber located in said pressure chamber and subjected externally to the pressure in said pressure chamber, a U-tube having one end connected with the retaining chamber and its opposite end subjected to the pressure in said pressure chamber, a body of liquid in the U-tube arranged for compressing the air within the retaining chamber relatively to the pressure in said pressure chamber, a part having a restricted orifice and forming part of the passageway through the U-tube and arranged for retarding the flow of the liquid from the retaining chambenia valve controlling the flow of air from the pressure chamber, and mechanism operatively associated with the retaining chamber and the valve for opening the latter by the expansion of the retaining chamber caused by the expansive action of the air. retained under pressure by the liquid in passing through said 'restricted;ori.fice upon the occurrence of a sudden reduction in the pressure in said pressure chamber.

4. An exhauster for a dry pipe sprinkler system containing air under pressure comprising a pressure chamber adapted to contain air under the system pressure, an air retaining chamber, a member movably mounted between and separating said chambers, said member subjected externally to the pressure within the pressure chamber, a restricted connection between said chambers, a body of liquid occupying said connection, a valve'controlling the flow of air from the pressure chamber, and means operatively associated with said member and the valve for opening the latter by a movement of said member caused by the expansive action of air' retained under pressure within the retaining chamber by the inertia of the liquid during a sudden reduction in the pressure in said pressure chamber.

5. An exhauster for a dry pipe sprinkler system comprising a pressure chamber adapted to contain air under the system pressure, an air retaining chamber located in said pressure chamber, a member movably mounted upon said retaining chamber and sealing the same said member subjected externally to the pressure Within the pressure chamber, a connection having one end communicating with said retaining chamber and its opposite end exposed to air under the pressure in said pressure chamber, a body of mercury occupying said'connection and movable therein by unequal pressure for equalizing the pressure on opposite sides of said member during slow changes in the system pressure said connection arranged for retarding the flow of the mercury upon the sudden reduction in the system pressure, a valve controlling the flow of air from the pressure chamber, and means operatively associated with said member and the valve for opening the latter by a movement of said member caused by a preponderance of pressure in said retaining chamber.

6. An exhauster for a dry pipe sprinkler system comprising a casing adapted to contain air under the system pressure, an air pressure retaining chamber located in the casing, a member movably mounted upon said chamber and sealing the same, said member exposed upon its exterior to the pressure Within the casing, a connection communicating with said chamber and with the pressure within the casing, a body of liquid occupying said connection, a tube formed of glass located in said connection and forming a resides of said member and for retarding the flowstricted passageway for retarding the flow of liquid through said connection upon the occur.- grence of a sudden reduction in the pressure within the casing, a valve controlling the flow of air from the casing, and means operatively associated with said member and the valve for opening the latter by a movement of said member by a preponderance of pressure within said chamber.

7. An exhauster for a dry pipe sprinkler system containing air under pressure comprising, a pressure chamber adapted to contain air under the system pressure, an air pressure retaining chamber located in said pressure chamber, a member movably mounted upon the retaining chamber and exposed upon its exterior to the pressure in the pressure chamber, a reservoir having an open end and located in the pressure chamber, a connection between said retaining chamber and said reservoir, a body of liquid occupying said connection, said connection having a restricted orifice arranged to permit the slow flowing or" the liquid to and from the retaining chamber for equalizing the pressure on opposite ing of the liquid, and means operatively associated with said member and arranged for exhausting the pressure from said pressure chamber by a movement of said member caused by the expansive action of the air retained in the retaining chamber by the liquid during a sudden reduction of the pressure within said pressure chamber.

8. An exhauster for a dry pipe sprinkler system containing air under pressure, comprising a pressure chamber adapted to contain air under the system pressure, an air pressure retaining chamber located in said pressure chamber, a member movably mounted upon the retaining chamber and exposed upon its exterior to the pressure in the pressure chamber, a connection forming a passageway between said chambers, a body of liquid occupying said connection, a tube formed of porcelain and having restricted aperture, said tube located in and forming part of said passageway, and means operatively associated with said member and arranged for ex haust-ing the pressure from the pressure chamber by a movement of said member caused by the expansive action of the air retained in the retaining chamber by the liquid during a sudden reduction of the pressure in said pressure chamber.

9. An exhauster for a dry pipe sprinkler system comprising a casing forming a pressure chamber, said casing having a connection through which air under pressure is adapted to be admitted from the system, a sealed expansible air retaining chamber located in the casing and subjected externally to the pressure in the pressure chamber, a reservoir located in the casing and in communication with the pressure chamber, a restricted connection between the reservoir and the retaining chamber, a body of liquid in said connection and arranged for compressing the air Within the retaining chamber relatively to the pressure within the pressure chamber, an exhaust valve controlling the flow of air from the casing, and valve actuating means operatively associated with the retaining chamber and the valve and arranged to open the valve by the expansion of the retaining chamber caused by the expansive action of the air retained in the retaining chamber by the liquid upon the occurrence of a sudden reduction or the pressure in said pressure chamber.

10. An exhauster for a dry pipe sprinkler system, comprising a casing forming a pressure chamber and having a connection through which air under pressure is adapted to be admitted from the system, a sealed expansible air retaining chamber located in the casing and subjected externally to the pressure in the pressure chamber, a reservoir located in the casing and in conununication with the pressure chamber, a restricted connection between the reservoir and the retaining chamber, a body of liquid in said connection and arranged for compressing the air in the retaining chamber relatively to the pressure Within said pressure chamber, an exhaust valve located in the casing and controlling the flow of air from the pressure chamber, a valve opening member movably mountedadjacent to the exhaust valve, a latch lever arranged for detachably engaging the valve opening member, a spring tending to move the valve opening member when the latter is released from said lever and for opening the valve, and means operatively associated with the retaining chamber and said lever for moving the lever by the expansion of the retaining chamber upon the occurrence of a sudden reduction of the pressure in the pressure chamber.

11. An exhauster for a dry pipe sprinkler system, comprising a casing forming a pressure chamber and having a connection through which air under pressure is adapted to be admitted from the system, a sealed expansible air retaining chamber located in the casing and subjected externally to the pressure in the pressure chamb r, a reservoir located in the casing and in communication with the pressure chamber, a restricted connection between the reservoir and the retaining chamber, a body of liquid in said connection and arranged for compressing the air in the retaining chamber relatively to the pressure in the pressure chamber, an exhaust valve seat surrounding an aperture through which air may flow from the pressure chamber, a clapper movable to and from said seat, a latch lever operatively associated with the retaining chamber and movable by the expansion of the latter by excess pressure in the retaining chamber, a valve clapper opening member movably mounted within the casing, a part upon said opening member normally located in spaced relation to the clapper, cooperating parts upon the latch lever and said opening member and arranged for detachably holding the latter out of engagement with the clapper, and a spring tending to move said opening member into engagement with the clapper and the latter from said seat when said opening member is released from the latch lever.

12. In a combination exhauster and accelerator for a dry pipe valve with an intermediate chamber, a casing having an inlet chamber and a pressure chamber, a diaphragm movably mounted upon the casing and separating said chambers, a connection through which air under the system pressure is adapted to be admitted to said inlet chamber, means forming a restricted connection between said chambers, a sealed retaining chamber located in said pressure chamber, a member movably mounted upon said retaining chamber and subjected externally to pressure within said pressure chamber, a reservoir located in said pressure chamber and open to the pressure in the latter, a restricted connection between the reservoir and the retaining chamber, a body of liquid in said connection and arranged for compressing the air in the retaining chamber, an

exhaust valve upon the casing for exhausting the air from said pressure chamber, means adapted to form a communication between said valve and the dry pipe intermediate chamber, valve actu-- ating means operatively associated with said member mounted upon the retaining chamber and with said valve and operable by the expansion of the retaining chamber, a drain valve located in said inlet chamber, and a connecting part between said diaphragm and the drain valve arranged for opening the drain valve when the diaphragm is moved by excess pressure remaining in the inlet chamber after the exhaust valve has been opened.

13. In a combination exhauster and accelerator for a dry pipe valve with an intermediate chamber, a casing formed of upper, lower and intermediate sections, means detachably securing said sections together, a diaphragm movably mounted between the lower and intermediate sections and forming an inlet chamber in the lower section and a pressure chamber in the upper and intermediate sectionameans forming a restricted connection between said inlet and pressure chambers, said casing having a connection through which air under the system pressureis adapted to be admitted to said inlet chamber, a sealed receptacle located in the pressure chamber, means detachably mounting said receptacle upon one of said sections, a reservoir located in said pressure chamber, a body of liquid in said reservoir, a connection having a restricted passageway between said reservoir and said receptacle, a flexible member upon the receptacle and responsive to pressure in the pressure chamber and to presture retained. in the receptacle by the liquid, an exhaust valve adapted to be connected with the pressure chamber, a pipe connection between said valve and the dry pipeintermediate chamber, a clapper arranged for opening and closing the exhaust valve, a clapper opening member, a bearing located in a. fixed position within the casing, a shaft upon said bearing upon which shaft the clapper and clapper opening member are pivotally mounted, a spring ttending to rotate said opening member into. engagement with the clapper for opening the exhaust valve, a latch lever operatively associated with said flexible member, said lever detachably associated with the clapper opening member, a drain valve located in said inlet chamber, and a connecting part between said diaphragm and the drain valve arranged for opening the latter when the diaphragm is moved by excess pressure remaining in the inlet chamher after the exhaust valve has been opened.

WILLIAM B. GRIFFITH. DAVID ARTHUR KELLER.

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