Fire sprinkler control apparatus

A fire sprinkler control apparatus which is adapted for connection between a network of connecting fluid flow lines which terminate in sprinkler heads and a water supply. The apparatus consists of a conduit having a first end and a second end. The first end is secured to a water supply and the second end is secured to a network of connecting lines. A solenoid valve is positioned at the first end of the conduit such that the flow of water from the water supply through the conduit to the connecting lines is controlled. An expansion tank is connected to the conduit. A sniffer valve is provided for coupling the conduit to an air source, such that the conduit, the expansion tank and all connecting lines may be pressurized with gas. A pressure switch is connected to the solenoid valve and with the conduit. The solenoid valve is opened to release water from the water supply into the conduit should the pressure in the conduit drop below a preset level.

The present invention relates to a fire sprinkler control apparatus. 
BACKGROUND OF THE INVENTION 
There has been a reluctance on the part of persons living in cold climates 
to install fire sprinkler systems in their premises, where the connecting 
fluid flow lines must be positioned in exterior walls. The reason for this 
reluctance is that fluid in exterior walls may freeze and burst the fluid 
flow lines resulting in extensive damage. 
SUMMARY OF THE INVENTION 
What is required is a fire sprinkler control apparatus which releases water 
into connecting fluid flow lines only when water is required to extinguish 
a fire. 
According to the present invention there is provided a fire sprinkler 
control apparatus which is adapted for connection between a network of 
connecting fluid flow lines which terminate in sprinkler heads and a water 
supply. The apparatus is comprised of a conduit having a first end and a 
second end, such that the first end may be secured to a water supply and 
the second end may be secured to a network of connecting lines. A valve is 
positioned at the first end of the conduit such that the flow of water 
from the water supply through the conduit to the connecting lines is 
controlled. An expansion tank is secured to and communicates with the 
conduit. Means is provided for coupling the conduit to an air source, such 
that the conduit, the expansion tank and all connecting lines may be 
pressurized with gas. A pressure switch is connected to the valve and the 
conduit. The valve is opened to release water from the water supply into 
the conduit should the pressure in the conduit drop below a preset level. 
The described fire sprinkler control apparatus releases water into the 
connecting fluid flow lines only when water is required to extinguish a 
fire. The expansion and contraction of the volume of pressurized air in 
the system which occurs with temperature fluctuations is accommodated 
through the use of the expansion tank. Water is introduced into the system 
only when a drop in pressure in the conduit causes the pressure switch to 
activate the valve. 
Although beneficial results may be obtained by using the fire sprinkler 
control apparatus as described above, there is a danger that a leak in the 
system may cause pressure levels to drop below the preset level thereby 
triggering the release of water. A release of water in the absence of a 
fire would fill the fluid flow lines with water as the sprinkler heads 
would remain closed. Having the fluid flow lines filled with water exposes 
the pipes to the consequential risk of freezing. Even more beneficial 
results may therefore be obtained by having a buzzer and a secondary 
pressure switch connected to both the buzzer and the conduit, such that 
the buzzer is activated to emit a warning tone should the pressure in the 
conduit drop below a preset level.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The preferred embodiment will now be described with reference to FIG. 1. 
The preferred embodiment, generally designated by reference numeral 10, is 
a fire sprinkler control apparatus which is adapted for connection between 
a network of connecting fluid flow lines 12 which terminate in sprinkler 
heads (not shown) and a water supply 14. The main components of fire 
sprinkler control apparatus 10 are a conduit 16, a solenoid valve 18, an 
expansion tank 20 and a primary pressure switch 22. 
Conduit 16 designates the primary water flow path. No water can flow from 
water supply 14 to connecting fluid flow lines 12 leading to the sprinkler 
heads without passing through conduit 16. Conduit 16 has a first end 24 
and a second end 26. First end 24 is to be secured to water supply 14. 
Second end 26 is to be secured to connecting fluid flow lines 12. Solenoid 
valve 18 is positioned at first end 24 of conduit 16. No water may flow 
from water supply 14 through conduit 16 to connecting fluid flow lines 12 
when solenoid valve 18 is closed. Expansion tank 20 is secured to conduit 
16 by connecting line 28. The purpose of expansion tank 20 will be 
hereinafter described in connection with the operation of apparatus 10. A 
connecting line 32 leads from conduit 16 to primary pressure switch 22 and 
a secondary pressure switch 36. A sniffer valve 60 is also positioned on 
connecting line 32. Primary pressure switch 22 is connected by electric 
cable 38 to solenoid valve 18, by electrical cable 40 to a alarm bell 34 
and by electrical cable 42 to a power source (not shown). Secondary 
pressure switch 36 is connected by electrical cable 46 to a buzzer 56 and 
by electrical cable 48 to a power source (not shown). A dual back flow 
preventer 50 is positioned at first end 24 of conduit 16. A manual shut 
off valve 52 is positioned at first end 24 of conduit 16 adjacent water 
supply 14. A drain 54 is secured at first end 24 of conduit 16. A pressure 
indicator gauge 30 is secured to conduit 16. 
The use and operation of fire sprinkler control apparatus 10 will now be 
described with reference to FIG. 1. Solenoid valve 18 should be placed in 
a closed position, such that no water from water supply 14 can enter into 
conduit 16. Sniffer valve 60 is then coupled to an air source (not shown) 
in order that connecting lines 28 and 32, conduit 16, expansion tank 20 
and connecting fluid flow lines 12 may be pressurized with air. The 
preferred pressure level is 60 pounds per square inch. The pressure level 
in conduit 16 can be checked with reference to gauge 30, as the pressure 
in connecting line 32 and the pressure exerted against primary pressure 
switch 22 is the same as in conduit 16. Should the pressure level in 
conduit 16 drop below 25 pounds per square inch primary pressure switch 22 
activates solenoid valve 18. As solenoid valve 18 opens water is released 
from water supply 14 into conduit 16 and via conduit 16 to connecting 
fluid flow lines 12 which lead to the sprinkler heads (not shown). At the 
same time as solenoid valve 18 is activated, alarm bell 34 is also 
activated to warn occupants of the residence. It must be noted the 
important role played by expansion tank 20. The volume of air in the 
system varies with temperature. An increase in temperature results in the 
expansion of the air, and expansion tank 20 provides the space necessary 
for such expansion. 
Secondary pressure switch 36 is provided as a precautionary measure. Should 
the pressure in conduit 16 drop below 50 pounds per square inch secondary 
pressure switch 36 activates buzzer 56 which emits a warning tone. The 
warning tone indicates that a slow pressure leak has developed. This 
permits systems maintenance to be performed before water is released into 
fluid flow lines 12. 
Once primary pressure switch 22 has activated solenoid valve 18 and water 
from water supply 14 has flowed through conduit 16 to connecting fluid 
flow lines 12, the remaining features are used in resetting the system. 
Back flow preventer 50 prevents water in connecting fluid flow lines 12 
and conduit 16 from flowing back to water supply 14. This is important in 
applications where a back flow of water could contaminate the water 
supply. Manual shut off valve 52 permits the supply of water to conduit 16 
to be shut off once a fire is extinguished in order that solenoid valve 18 
may be reset to a closed position. Drain 54 permits conduit 16 and 
connecting fluid flow lines 12 to be drained of water once a fire is 
extinguished, in order that the system may again be pressurized. 
It will be apparent to one skilled in the art that modifications may be 
made to fire sprinkler control apparatus 10 without departing from the 
spirit and scope of the invention. In particular, many of the preferred 
features may be removed while still leaving apparatus 10 functional. In 
additional alternate types of switches and valves may be used having 
regard to the intended function. Similarly, the arrangement of components 
may be configured in a different manner having regard to the intended 
function.