Quick response dry pipe sprinkler system
AssigneeCentral Sprinkler Corporation
InventorsRalph A. Loh, James E. Golinveaux
Life of this patent
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Abstract
A gas charged fluid flow line of a dry pipe sprinkler system is continuously monitored to detect rate of loss of pressure (dp/dt). The rate of pressure loss is used to detect whether there is an open sprinkler head in a sprinkler grid of the system. Detection of an open sprinkler head and opening of a dry valve may occur in a matter of a few seconds, allowing for a quick response to a fire condition and accurate discrimination of a pressurized gas leak condition. The system may operate at charge pressures in the range of about 7 psig to about 15 psig.
Claims23
A method of operating a dry pipe sprinkler system, the method comprising monitoring the charged fluid flow line by:
- (a) sensing pressure in a gas charged fluid flow line of the system and generating a signal representing instantaneous gas pressure in the fluid flow line;
- (b) calculating a rate of change of the instantaneous gas pressure;
- (c) comparing the rate of change to a predetermined negative rate of change value;
- and
- (d) outputting an open sprinkler head signal if the rate of change is more negative than the predetermined negative value, thereby detecting sprinkler openings in the system.
Apparatus including electronic circuitry adapted for use in a dry pipe sprinkler system to monitor a gas charged fluid flow line in the system, the electronic circuitry comprising:
- (a) an input for receiving an electrical signal representing the instantaneous gas pressure in the gas charged fluid flow line;
- and
- (b) a processor for using the electrical signal to calculate a rate of change of the instantaneous gas pressure and compare the rate of change to a predetermined negative rate of change value, the processor outputting an open sprinkler head signal if the rate of change is more negative than the predetermined negative value.
A method of controlling the state of a primary fluid flow supply valve associated with a dry pipe sprinkler system, the method comprising:
- (a) detecting the occurrence of an open sprinkler in the system by monitoring a rate of change of gas pressure versus time in the fluid flow line and determining when the rate of change versus time is more negative than a predetermined negative value;
- and
- (b) opening the primary fluid flow supply valve to allow fire retarding fluid to flow through the fluid flow line when the rate of change versus time is determined to be more negative than the predetermined negative value.
A method of monitoring a dry pipe sprinkler system to detect pressurized gas leaks in a gas charged fluid flow line in the system, the fluid flow line having an operating pressure, the method comprising the steps of:
- (a) sensing pressure in a gas charged fluid flow line of the system;
- (b) comparing the sensed pressure to a preset value which is less than the operating pressure;
- (c) recharging the fluid flow line to the operating pressure if the sensed pressure is below the preset value by operating a gas compressor which has its output connected to the fluid flow line;
- and
- (d) outputting a pressurized gas leak signal if the fluid flow line pressure is not restored to the operating pressure within a predetermined time period.
A method of monitoring a dry pipe sprinkler system to detect pressurized gas leaks in a gas charged fluid flow line in the system, the fluid flow line having an operating pressure, the method comprising the steps of:
- (a) sensing pressure in a gas charged fluid flow line of the system;
- (b) comparing the sensed pressure to a preset value which is less than the operating pressure;
- (c) recharging the fluid flow line to the operating pressure if the sensed pressure is below the preset value by operating a gas compressor which has its output connected to the fluid flow line;
- and
- (d) outputting a pressurized gas leak signal if the gas compressor is actuated to restore pressure more than a predetermined number of times in a fixed time period.
A method of monitoring a dry pipe sprinkler system to detect pressurized gas leaks in a gas charged fluid flow line in the system, the method comprising the steps of:
- (a) sensing pressure in a gas charged fluid flow line of the system and generating a signal representing instantaneous gas pressure in the fluid flow line;
- (b) calculating a rate of change of the instantaneous gas pressure;
- (c) comparing the rate of change to a predetermined negative rate of change value;
- and
- (d) outputting a pressurized gas leak signal if the rate of change is negative and less negative than the predetermined negative value.
Dependencies are inferred from the claim text.