US1762009A - Constant-alarm device - Google Patents

Description

G. CARLSON CONSTANT ALARM DEVICE Filed March 14, 1927 Patented June 3, 1930 UNITED STATES CORPORATION OF MASSACHUSETTS imzroe PATENT -oFric1-:; 1

HJALMAR G. GARLSON, or WORCESTER; MASSACHUSETTS, ASSIGNOR 'ro RocKwoo SPRINKLER COMPANY or MASSACHUSETTS, or WORCESTER, M ssAcgUsErrS, A

CONSTANT-ALARM DEVICE Application filed March 14, 1927. Serial No. 175,283.

\Vhen water spurts from an opened sprinkler on an automatic sprinkler system it is important to have a continuous alarm sounded. The usual means provided consists of three elements: a check valve in the main riser pipe,' having a grooved annular seat, an automatic drip-chamber connected by pipes to both the groove and to an alarm means such as a water motor or electric circuit closer operating a gong. The drip chamber has a valve-controlled waste outlet for Wasting part of the water as it enters, to slow down the rate of filling it completely. The purpose of the drip chamher is to prevent the gong from being rung by a Water hammer. Water hammer is the popular name given to the sudden rise in pressure which occurs 'whenever'the rate of flow of water in a supply system is Suddenly reduced. Such an increase of pressure will cause the check valve ,to lift and admit water to both the system and the 'dripchainber. a A

It has been found in practicethat the time of duration of a water hammer is quite variable and. depends both upon its force andupon the amount of air trapped .in the extremities of the sprinkler pipes.

takes a given rate of flow of water, up the riser to cease its upward motion and start back again under theinfluences of gravity and the compressed air. The return wave off iowing water re-seats the valve, thus cutting 05 the supply of water to the drip chamber. "So desirable is it to prevent water hammers from causing the alarm to ring.-

' chamber will solve the foregoing problem,

it introduces a new trouble for such increase in size is inpart itself the cause of'discon- 1 tin'uous ring ng of the gong when the hpward flow of water by the check valve is due, not to waterhammers, but to an open sprinkler. Indeed it maycause entire fail The more such air there is, the longer time it ure of the gong to'ring because of the suction on the back of the check valve induced by the flow of water through the groove when the-valve has opened just enough to supplyone or two open sprinklers. When a sprinkler opens the first rush of water there from is not caused by the outside water supply pressure, but by the air bottled up in the extremities of'the sprinkler lines. This air' pressure must fall a few pounds per square inch before the water supply pressure can overcome the differential load on the upper side of the check valve, caused by the smaller area of its under side. The consequence is that when release takes place the valve bounds open clear to its extreme position and remains there until the motion of the water by it is arrested by the rising air pressure and a return wave orfiow takes place. Then the valve may he slapped back to its seatagain before the drip chamberhas been entirely filled. and-an alarm sounded; A

or this action may be sufiiciently sluggish to occupy more than enough time to fill the drip chamber and ring the gong, onlyv to then occur and stop the water supply to drip chamber and gong, thereby stopping the alarm. It was to correct this action that the device shown in vPatent Number 1,051,-

266, patented Jan. 21,1918, wasv invented by George I. Rockwood. Inthat invention a small auxiliary check-valve, having a capacity for supplying two orthreesprinkler heads, was pipedaroiund the main check valve, the purpose being to prevent most of the above described {return .wave ofxthe opened. Thisiwas effected so throttling the water supply through the auxiliary check valve that the purely inertia effects of the stream of'water in the riser were reduced with the difliculties described.

The principal object of my invention-is water after the small: check valve has V to provide automatic and positively operat ing means for controlling the reseating of the auxiliary check valve of the Rockwood type of alarm check valve during the period of existence of such return wave as there is when the auxiliary check valve opens in response to the flow from an opened sprinkler.

Other objects and advantages of the in vention will appear hereinafter.

Reference is to be had to the accompanying drawing which is a central sectional view of an alarm valve of the Rockwood type with a preferred embodiment of this invention applied thereto. 7

I have shown this invention as applied to a well known type of alarm valve device comprising the casing 9 and'the valve, which consists of two plates 10 and 11 compressing between them a rubber ring. The valve rubber ring rests on an annular valve seat 12. The area of the valve on the under side, which is exposed to the main water pressure is less by the area of the annular seat than the area of the valve on the upper side, which is subjected to substantially the same pressure above. In other words, it is a differential valve which will remain closed if the pressure per square inch on both sides is the same. This valve is pivoted at 13. The valve seat 12 is provided with a groove 14 which, in this case, as usual, is connected by a pipe 25 with an alarmbell 26 and adapted to operate the same when the valve opens and this groove is exposed to the pressure of the water in the system. This construction, although commonly used, is open to the objection above specified and is also aflected by the fact that the current of water rushes by this groove at a high velocity, thus at times relieving it of some of the pressure. The usual drip chamber is employed but is not shown.

A bypass 15 is provided allowing the water from the system constantly to enter pressure of the water in the main.

a chamber 16 outside the valve chamber so that this chamber will remain under the This chamber has an opening into the interior of the valve casing which is provided with another difierential valve 17 having a higher ratio of difference between the two areas than is the case with the valve 11. Therefore the valve 17 will open under a lower reduction of pressure above and if only one or two sprinkler heads are open this valve 17 will open and allow the water to pass by into the sprinkler system even when the valve 11 is closed. All this is shown in the said Rockwood patent.

'The valve 17 besides closing the chamber 16, also closes the end of a tube 19 connected with pipe 20 which is connected with the alarm pipe 25 to which the water from the groove 14 flows. ,Therefore the alarm will be operated by either or both. The valve 17 details herein disclosed, but what I is pivoted at 21 on a lever 23. This arrangement minimizes the difiiculties above specified but does not entirely eliminate them ii only the parts that have been so far described are employed. It will be understood of coursethat if the valve 11 is open, the pressure on the valve 17 will close it, and the operation of the alarm will be provided for only from the groove 14.

F or the purpose of preventing the sudden closing of the valve 17 by the reverse flow of water, thus allowing the water to reestablish its upward flow through the pipe 20 so as to hold the valve 17 open and cause the alarm to operate continuously, I provide a flexible diaphragm .30 in a chamber 31 at the SlClG Ol the valve casing. The water is admitted to the inner side of the diaphragm by a passage 36. Secured to this diaphragm is a rod 32 extending through the passage 36 and pivoted at 33 to the lever 23. The chamber 31 behind the diaphragm 30 is connected by a comparatively small passage 35 with the by-pass 15 to keep the chamber 31 under the same pressure as the chamber 16. On account of these conditions'it will be understood that the chamber 31 on both sides of the diaphragm 30 is constantly full of water under pressure and that the diaphragm will move one way or the other according to changes in the pressure of the water.

The swing of the lever and the movement of the valve are limited by the length of the rod 32.

With any reduction of pressure in the system below that in chamber 31, the excess pressure on diaphragm 30 will assist in opening valve 17 against its differential load, thereby shortening the time required to soundthe alarm when a sprinkler opens. On the other hand, the restricted size of the port between passage 35 and chamber 31 limits the speed of outflow of the water from that chamber, thus causing the diaphragm to actas a clash-pot, slowing down the return motion of the valve 17 toits seat. In operation, therefore, whether one head opens or more heads than one, a continuous water pressure is kept on the alarm gong motor regardless of whether or not the intensity of the return wave of pressure is suflicient to reach and reseat the main valve 11.

, Although I have illustrated and described only a single form ofthe invention, I am aware ofthe fact that modifications can be made therein by any person skilled in the art Without departing from the scope of the invention as expressed in the claims. Therefore I do not wish to be limited to all. the do claim is 1. The combination with an alarm valve casing and valve, of a by-pass having one end opening on the main water pressure side by-pass' and having an opening into the intenor of said valve casing on the other side of the valve, a tube in said chamber connected to conduct water to an alarm device, a valve for closing said opening, said tube being in position for its end to be closed by the valve when in closed position, a second chamber in open communication with the interior of the valve casing, a diaphragm across the second chamber, a rod connected with said diaphragm and' connected with said second valve, and a restricted passage to admit water into the second chamber behind the diaphrag-n from the main water pressure side of the valve casing, the pressure of water from the chamber behind the diaphragm toward the valve acting to slow down the closing of the second valve.

2. The combination with an alarm valve casing and valve, of a tube connected to conduct water to an alarm device, a valve for closing said tube, said tube being in position for its end to be closed by the second valve 25 when in closed position, a chamber in open communication with the interior of the valve casing on the outlet side of the valve, a

diaphragm across the chamber, a restricted passage from the main water pressure side of 30 the valve casing to admit water into the chamber behind the diaphragm, a rodconnected with said diaphragm and connected with said second valve for restricting the closing of the valve after it is opened.

3. The combination with a dry pipe valve casing and a valve, of a chamber connected with the interior of said valve casing on the I outlet side of the valve, an open ended tube passing through said chamber connected to conduct water to an alarm device, a valve for closing said opening and tube, a second chamber in open communication with the interior of the valve casing, a diaphragm across the second chamber, a rod connected with said diaphragm and connected with the second valve, said second chamber being ing of the valve and preventing the leverfrom moving backrapidly to seat the valve after'the valve is once'opened V 5. The combinationwith a dry pipe valve, of a by-pass from the water pressure side of the valve, an alarm connected with'the bypass, means leading from the seat of the; valve to operate said alarm, means leading from the by-pass to operate said alarm, a

differential valve for closing the connection of thenby-pass to said alarm, the second valve being constructed and arranged to open under a lower "difference of pressure than the first named valve, a diaphragm chamber connected with the by-pass by a restricted opening, and means for connecting the diaphragm with the second; valve for assisting the opening of the second valve. 7

6. The combination with a dry pipe valve, of an alarm, means for conducting water to said alarm having two inlets, one being under the valve and the other above it, a

second valve for closing the other inlet, a

chamber connected with the water pressure side of the system having a restricted inlet and a diaphragm in said chamber connected with the second valve to operate it, the chamber on one side of the diaphragm being connected with the restricted inlet and that on the other side being connected with the first namedinlet, the diaphragm and restricted inlet being so proportioned as to retard the closing ofthe second valve.

- In testimony whereof I have. hereunto aflixed my signature.

-HJALMAR G. CARLSON.

open by a restricted orificeto the main water a pressure side of the valve casing to admit water slowly into the second chamber be-,

hind the diaphragm and discharge it slowly to assist the opening and slow down the closing of the second valve. I

4. The combination with a dry pipe valve and an alarm, of a by-pass from the main water pressure side of the valve, a chamber connected with said by-pass, a tube through said chamber, means'forconnecting said tube to the alarm, said chamber opening into the main valve chamber, a differential valve for closing said opening and closing the end of said tube, a lever connected with the second valve, a second chamber connected with the by-pass by arestricted opening, and a diaphragm in said second chamber con nected with said lever for limiting the open-

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