US1608105A - Dry-pipe sprinkler system - Google Patents

Description

1,608,105 g. w. KNIGHT DRY PIPE SPRINKLER SYSTEM Filed Dec. 9, 1924 INVENTOR. IRA W. KN IGHT A TTORNEYS Patented Nov. 23, 1926.

UNITED. srArl-zs PATENT OFFICE.

IRA wQimre'nr, OF CRANSTON; RHODE ISLAND, ASSIGNOR TO GENERAL FIRE EX- TING-UISHEB COMPANY, OF PROVIDENCE, RHODE ISLAND, A CORPORATION OF DELAWARE.

nnr-rrrn srnmxmn sYsm-p Application filed December 9, 1924. Serial No. 754,848.

This invention relates to improvements in dry pipe sprinkler systems having a booster pump for providing a suflicient 0 rating head to insure adequate sprinkler discharge.

More especially it relates to apparatus or effecting the operation of said pump before dry pipe valve opens, whereby its tripping may be hastened and the discharge v accelerated.

In my pending. application Serial No. 7 54,847 there is dlsclosed a system in which the actuation of the booster pum is dependent upon the tripping of the ry pipe valve, there being a pressure responsive device which efiects starting of the pump motor upon rise of pressure in the intermediate chamber of that valve. where the water pressure supply is extremely low, or when it is greatly reduced by adjacent fire engine or.other pumps; a suflicient rise of pressure to effect pump actuation ma not occur in the intermediate chamber; or 1t may be much delayed, due to the necessity of bleeding the air pressure to practically zero, before the pressure is low enou'gh to let the valve trip.

The presentinvention is to cause earlier starting of the pump, thus to bring about the positive opening of the dry pipe valve irrespective of the supply pressure. A feature is the arrangement and combination of circuits through an accelerator which responds to a drop in pressure inthe distributin g line,. and through a circuit closer which. responds to a rise of pressure, to the end that each device may perform its indi- 'vidual function without interfering with the other, and yet the separate actions of both shall combine to produce early and continuous operation of the pump.

' Apparatus by which the invention may be practiced comprises the usual supply and distributing piping with a dry pipe valve and abooster pump interposed between the supply". main and the valve. The pump is driven by an electric motor whose current passes through a starting and controlling rheostat the actuation of which rheostat is -in turn subject to a shunt circuit from the main power wires. This shunt circuit may be set open or closed by the armature of-a.

solenoid the energization of which may be efiected by either a'pressure fall device attached to the distributing pipes, or by a ressure rise device whic may for examp e be In places connected with the intermediate chamber of the dry pipe valve and normally 0 en to atmos here as disclosed in my sai pending app ication. This double control is accom plished by arranging the energizing circuit in parallel thro'u h thesetwo devices so that the closure of eit er establishes current flow.

The accelerator of the present invention is connected with the system on the air side of the dry pipe valve and may be set to respond when the air pressure has fallen to a predetermined degree which may either be that at which the dry pipe valve would open if there were present a normally suflicient 'anddesirable water pressure, of if desired may be somewhat in excess of that, in which case the same effect is gained as if there were a high water pressure. The bleeding-of the air system through'an open sprinkler head down to this pressure operates to close the ener 'zing circuit, and so to effect operation of t e pump. This properly builds up water pressure against the still closed dry pipe valve, and causes it to open which thus occurs long before the air pressure has gotten. down to the level corresponding to the actually low Water pressure. The flow of water into thevalve chamber also fills the branch pipe leading to the circuit closer which responds to rise in pressure, and operates it in throw its switch. Thus, the ener gizing circuit is doubly closed, as it were,

cause the pressure rise device,'having. already operated, keeps the energizing circuit closed. Thus the pump action, initiated by pressure fall, is maintained notwithstanding the ensuing pressure rise, giving a continuous water pressure supply to the sprinkler.

It is intended that the suitable expression in the appended b patent shall cover, cbaims, whatever features ofpatentable novelty exists in the invention disclosed.

In the accompaning drawings the single figure is an elevation showing a booster sprinkler system embodying the invention,

parts being shown somewhat diagrammatically.

Referring to the drawings, the supply main 10 leads to a booster pump 12 which discharges into the riser 14 leading to the dry pipe valve 18. As illustrated this valve is of the differential type, although the application of the invention is not limited to' that, in which a water clapper 16 holds bacls the water in riser 14 so long as the pressure upon the clapper 20 of air in the distributing pipes 22, is great enough, and until said pressure is reduced by escape of air through the sprinkler heads 24, when one or'more is opened.

The opening of the dry pipe valve permits the water to flow into its intermediate chamber, thereby closing its vent 26 which is normally open to atmosphere, and thence through a small pipe 28 to a device 30 1n which a switch 32 is operated by rise of pressure to close a circuit from the source of energy 34 through solenoid 86. The armature of the latter when drawn upward upon energization of the solenoid rests across terminals 38 of a shunt'circuit S whose current controls the operation of: rheostat 40. This in turn governs the operation of the motor 42 which drives the booster pump 12.

If the supply pressure in main 10 and and riser 14 Were very low, due perhaps to other demands being made upon the supply, the bleeding reduction of the air pressure might not effect a tripping of the dry pipe valve or might be very long in doing so, and consequently the booster pump would not be started bythe pressure rise device. To prevent this, the present invention pro vides another circuit closer 44, herein called an accelerator, connected to the distributing line 22 beyond the dry pipe valve on the air side. This operates upon fall of pressure to close a switch 46 which forms part of the energizing circuit through-the solenoid 36. This part of the circuit is arranged in parallel with that part which passes through the other circuit closer 30, so that if either switch is closed, the circuit from the battery through the solenoid will be made. Since the accelerating device operates upon fall of pressure in the distributing pipe to close its switch and thus to effect pump operation, it acts oppositely upon rise of pressure and opens the switch. But before its opening can thus occur, the pressure generated by the booster pump will have opened the dr pipevalve and caused the pressure rise evice 30 to close its switch, Thereafter it will not matter that the switch of the pressure fall device is opened by the elimination of the low pressure condition, for the circuit through the solenoid will still be closed and the pump thus be continued in motion.

The startin of the pump is efiected by the pressure "all device ahead of the opening of the dry pipe valve, whenever the air pressure has been reduced following the opening of a sprinkler head to a degree which may be predetermined to give as early orlate response as desired. By this means, in a locality where the city water pressure is low or is liable to fail, but where the pump 12 is capable of boosting the pressure to a certain known standard at the dry pipe valve, the accelerator 44 can be sctso that the valve will open when the air has. fallen to one-sixth of that pressure (assuming the valve to operate on a 6 to 1 ratio of water pressure to air pressure)- without waiting for the air pressure to drop to one-sixth of the actual city Water supply pressure. This makes the action of the system analogous to that of a system having the said standard of pressure actual- ,ly available in the city supply. Once started, the pump is maintained running by vthe pressure rise device, so that an effective discharge will be continuous until the system is reset.

I claim:

1. A sprinkler system having the combination, with a dry pipe valve and a booster pump, of pump control means havlng a connection with the system on the air side of said valve and another connection with the system on the delivery side of the pump, and comprising devices responsive to pressure changes in the system adapted upon the fallof pressure on the air side of said valve to initiate actuation of the pump and upon rise of pressure on the delivery side of said pump to maintain the pump actuation.

2. A sprinkler system having the combination, with a dry pipe valve and a booster pump, of pump control means including an electromagnetic device having two circuit closers; a pressure responsive device connected to the system on the air side of said dry pipe valve and adapted upon fall of pressure in said pipes to set one of said circuit closers whereby the pump is put in operation, and another pressure responsive device connected to the system and adapted upon rise of pressure therein to set the other of said circuit closers so as to continue the position of the electromagnetic device and maintain pumpoperation after the first said pressure responsive device has been made inefiective therefor by rise of the system-pressure.

3. A sprinkler system having the combination, with a dry pipe valve and a booster pump, of pump controlrmeans including an electromagnetic device having two circuit closers; a pressure responsive device connected to the system on the supply side of the air clapper of said valve normally open to atmosphere and adapted upon rise of pressure in the system to set one of said circuit closers to effect operation of said pump; and another pressure responsive device connectedto the system on the air side of said clapper and adapted upon fall of system pressure to a predetermined degree above the atmosphere to set the other circuit closer for effecting pump operation, thereby causing a rise of pressure in the system to which the first mentioned device responds to efiect continuation of said pump operation.

Signed at Providence, Rhode Island, this 17th day of October, 1924- 'IRA W. KNIGHT.

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