Patent Application
20060272832
This invention relates generally to fire suppression systems used in buildings, restaurants and other commercial kitchens, and more particularly, to blow-off caps used on nozzles within the fire suppression systems.
Fire suppression systems provide an integral service to commercial kitchens, which use multiple cooking appliances (e.g. chain broilers, deep fryers, broilers, cook tops, and the like) to cook large quantities of food. The cooking appliances are often operated at high temperatures for extended periods of time, creating a large amount of grease and other effluent.
Fire suppression components are located over the top of the cooking appliances, aimed inside partially enclosed cooking appliances, and are within hoods and ducts associated with the exhaust system. When a hazardous condition is detected, a fire suppression agent is discharged through a nozzle to eliminate the hazardous condition. The fire suppression agent may be, for example, a chemical agent, water, or a combination of the two.
Due to the large amount of effluent present in the location of the nozzles, clogging of the orifice or orifices through which the fire suppression agent is discharged needs to be prevented so that the system activates correctly when needed. A cap is therefore affixed to the nozzle. The cap is to be blown or pushed off the nozzle, or broken or burst, by the pressure created when fire suppression agent is discharged.
A silicone rubber cap has been used to cover the end of the nozzle. However, the rubber cap deteriorates due to effluent build up and the high temperature experienced in the exhaust area over broilers and other cooking units. A brass cap held onto the nozzle with a retaining clip has also been used. The retaining clip weakens over time due to, for example, the extreme temperature gradients, allowing the cap to fall off the nozzle. Also, grease accumulates inside the cap and nozzle, effectively freezing the cap onto the nozzle and/or clogging the orifice.
Therefore, a need exists for a blow-off cap and nozzle assembly capable of withstanding the extreme conditions experienced in commercial kitchen applications, while still allowing the blow-off cap to be pushed off the nozzle during a fire discharge situation. Certain embodiments of the present invention are intended to meet these needs and other objectives that will become apparent from the description and drawings set forth_below.
In one embodiment, a discharge assembly for use with a fire suppression delivery system comprises a nozzle having an outer nozzle surface. The nozzle also has an inlet end configured to receive a fire suppression agent and a discharge end with an orifice therein to dispense the fire suppression agent in a desired manner. A blow-off cap has an open-ended cavity shaped to receive the discharge end of the nozzle and to cover the orifice. The cavity includes an interior cap surface that is located in close proximity to the outer nozzle surface of the nozzle when the blow-off cap is mounted on the discharge end of the nozzle. A receptacle is formed in at least one of the outer nozzle surface of the nozzle and the interior cap surface of the blow-off cap. A retention element is fit within the receptacle and engages the outer nozzle surface and the interior cap surface to provide a predetermined amount of retention resistance to retain the blow-off cap on the nozzle.
In another embodiment, a blow-off cap for use on a nozzle in a fire suppression system comprises a cover and an O-ring. The nozzle has an outer nozzle surface and inlet and discharge ends. The inlet end is configured to receive a fire suppression agent and the discharge end has an orifice therein to dispense the fire suppression agent in a desired manner. The cover of the blow-off cap comprises a cavity configured to receive the discharge end of the nozzle. The O-ring is fixed within the cavity and is snappingly received over the outer nozzle surface. The O-ring and nozzle provide resistance to retain the blow-off cap on the nozzle until a system pressure builds up sufficient to push the blow-off cap off the nozzle.
In another embodiment, a fire suppression system comprises a fire suppression delivery system for delivering fire suppression agent. A nozzle has an outer nozzle surface and inlet and discharge ends. The inlet end is configured to receive the fire suppression agent and the discharge end has an orifice therein to dispense the fire suppression agent in a desired manner. A blow-off cap has an open-ended cavity shaped to receive the discharge end of the nozzle and to cover the orifice. The cavity includes an interior cap surface that is located in close proximity to the outer nozzle surface of the nozzle when the blow-off cap is mounted on the discharge end of the nozzle. A receptacle is formed in at least one of the outer nozzle surface of the nozzle and the interior cap surface of the blow-off cap. A retention element is fit within the receptacle and engages the outer nozzle surface and the interior cap surface to provide a predetermined amount of retention resistance to retain the blow-off cap on the nozzle.
The foregoing summary, as well as the following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. It should be understood that the present invention is not limited to the arrangements and instrumentality shown in the attached drawings.
The chain broiler 100 has an open or substantially open top end 120 to exhaust effluent. The open top end 120 is placed beneath an exhaust hood 122, which is connected to an exhaust duct within an exhaust system. The exhaust system may provide ventilation for multiple areas within a kitchen, such as additional hoods, chain broilers, upright broilers, ovens and the like.
The fire suppression delivery system 101 uses a number of interconnected controls, panels, pipes, tanks, bottles, nozzles, blow-off caps, detectors and the like. The fire suppression delivery system 101 may be designed based on the cooking appliances it will be used with. A hazard zone, such as a flat, level and/or rectangular surface including all of the cooking hazards of the protected appliances under the hood or hoods, may be defined when designing the number, flow, location and aiming of the nozzles. Fire suppression is provided to the hazard zone as well as to the hood 122 and other locations within the exhaust system.
A control unit 124 is located near the hood 122 and provides a control panel 126 to allow operation of the fire suppression delivery system 101. The control panel 126 may be accessible from the outside of the control unit 124, or may be behind a door or window. The control panel 126 provides controls to a user, such as an on/off switch 154 and a manual activation switch 156 for manually activating fire suppression. Alternatively, emergency control of the fire suppression delivery system 101 may be provided simply through a manual pull station and a fuel shut off.
One or more bottles 128 of fire suppression agent may be installed within the control unit 124, a separate enclosure, or affixed to a wall or other location. A water source 129 may also be supplied to the fire suppression delivery system 101. The bottle 128 is connected to a pipe 130, hose or other conduit suitable for carrying the fire suppression agent and able to withstand hot and fluctuating temperatures. An actuator 168 may be connected to the bottle 128 or between the bottle 128 and the pipe 130. The pipe 130 extends out of the control unit 124. The pipe 130 is bent in one or more locations, if necessary, such as at elbow 132, and extends into the hood 122. The water source 129 may also be connected to the actuator 168 and allowed to flow through pipe 130, or may be connected to a second actuator and pipe (not shown)
One or more nozzles 134, 136 and 138 are interconnected to the pipe 130 and may be positioned uniformly under the hood 122 from the first end 112 of the chain broiler 100 to the second end 114. The nozzles 134-138 are configured to dispense the fire suppression agent through one or more orifices. Each of the nozzles 134-138 has a flow rating, angle of coverage, and/or spray pattern, and the type and configuration of nozzles 134-138 may vary. For example, both nozzles 134 and 136 may provide a wide angle of coverage while the nozzle 134 has a flow rating of 1 and the nozzle 136 has a flow rating of 2.
A blow-off cap 140, 142 and 144 is installed on each of the nozzles 134, 136, and 138, respectively. The blow-off caps 140-144 cover the orifice(s) on the nozzles 134-138, each forming a discharge assembly which prevents the nozzles 134-138 from clogging with grease and/or other effluent. It should be understood that additional nozzles 134-138 and blow-off caps 140-144 may be installed to provide protection to other ventilation equipment such as ducts, plenums and filters.
One or more detectors 146, 148 and 150 may be connected to the control unit 124 by way of one or more wires 152. The detectors 146-150 detect a condition that needs to be suppressed, such as a fire, excess smoke, or heat beyond an acceptable limit, and report the condition to the control unit 124. Other methods of detection may be used.
When the detectors 146-150 detect a condition or the manual activation switch 156 is activated, the control unit 124 opens the connection between the bottle 128 and the pipe 130, such as by energizing the actuator 168. The fire suppression agent discharges into the pipe 130 at a minimum pressure. The fire suppression agent enters each of the nozzles 134-138 and applies a system pressure to each blow-off cap 140-144 through the orifice. When the system pressure builds up to a sufficient level, the blow-off cap 140-144 is pushed off the nozzle 134-138. The fire suppression agent is discharged out of the orifices of the nozzles 134-138, into the hood 122 and the top end 120 of the chain broiler 100. By way of example only, the blow-off caps 140-144 may be designed to blow off the nozzles 134-138 when experiencing system pressure within a range or predetermined limit or limits, such as above a minimum preset pressure. The blow-off caps 140-144 stay connected to the respective nozzles 134-138 through a lanyard 158, 160 and 162, chain or other device after a fire discharge situation.
One or more fire suppression agents may be used. For example, a fixed amount of wet chemical agent from the bottle 128 may be discharged through the nozzles 134-138. Alternatively, following the discharge of a wet chemical agent, water from the water source 129 may be discharged through the nozzles 134-138, such as in a hybrid system. Alternatively, a clean extinguishing agent may be used instead of a wet chemical agent. A clean extinguishing agent, such as a liquefied gas product, is discharged out of the nozzle 134-138 as a liquid and then vaporizes. Optionally, a foam based agent may be used. One or more nozzles may be used to supply the fire suppression agent while the remaining nozzles are used to supply water. Optionally, a dry chemical agent may by applied using a first set of nozzles while a second set of nozzles apply water.
The wall portion 184 has a thickness T1 at a first end 182 and a thickness T2 at a second end 183. The wall portion 184 may have a beveled inner edge 188 along the first end 182. A receptacle 178 with a depth D1 and a height H1 is formed in the cavity 176, starting at a height H3 from the interior cap surface 174 of the closed end 177. The receptacle 178 forms a first angle 180 with the interior cap surface 174 and a second angle 181 with a protrusion 164. First and second angles 180 and 181 may be approximately 90 degrees. The receptacle 178 may be a groove which retains a retention element, such as an O-ring. The depth D1 and the height H1 may vary depending upon the size of the retention element or O-ring, operating pressures of the fire suppression delivery system 101, and the like. It should be understood that the details illustrated and discussed in
The receptacle 204 may be formed adjacent the first portion 202 as a groove having a diameter D11 and a height H11. The receptacle 204 is configured to snappingly receive the O-ring 190 (
The third portion 210 is formed adjacent the second portion 206 and has a diameter D13 and a height H13. The diameter D13 is substantially equal to or slightly less than the diameter D3. A surface 214 of the third portion 210 is configured to rest against a surface 165 of the protrusion 164. The recess 212 has a diameter D14 and a height H14 which may be varied depending upon the height H4 of the cavity 176. Therefore, a total height H15 of the cap receiving portion 200 is substantially equal to, or slightly greater than, the height H4. The recess 212 may be configured to receive an interconnecting member attached to the blow-off cap 140. As stated previously with
A puff test may be conducted to ensure that the blow-off cap 140 is pushed off the nozzle 134 at the appropriate system or discharge pressure, and may be measured in pressure per square inch (psi). Therefore, the receptacles 178 and 204 and retention element or O-ring 190 provide a predetermined amount of retention resistance to retain the blow-off cap 140 on the nozzle 134. The discharge pressure range may be based on the normal operation of the fire suppression delivery system 101. For example, the fire suppression delivery system 101 may be set to operate normally between 45 and 65 psi, that is, the pressure range experienced at the nozzle 134 during a fire discharge situation will be between 45 and 65 psi. The discharge assembly 240 may be designed to separate at, by way of example only, 50 psi. Thus, when the system pressure builds up to the sufficient level of 50 psi, the blow-off cap 140 is pushed off the nozzle 134.
The receptacle 204 retains the blow-off cap 140 on the nozzle 134 under the defined system conditions. The discharge pressure needed to push the blow-off cap 140 off the nozzle 134 may be refined by adjusting the size of one or both of the receptacles 178 and 204. For example, by increasing the depth 208 (
In addition, a minimum operating limit or range may be established, ensuring that the discharge assembly 240 withstands a predetermined level of vibration. By way of example only, a vibration test using 0.06 inches of displacement at 10 hertz for 8 hours may be conducted during which it is verified that the blow-off cap 140 stays on the nozzle 134. The discharge assembly 240 is also designed to withstand hot and cold temperature gradients experienced during cooking operations, such as fluctuations between 70 degrees and 200 degrees. Optionally, a single receptacle may be formed in either the blow-off cap 140 or nozzle 134 to retain the O-ring 190. The receptacle may be adjusted in height, width, and/or diameter to adjust the retention resistance of the discharge assembly.
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
The application relates to and claims priority from provisional patent application Ser. No. 60/683,673, titled “CB BLOW-OFF CAP”, filed May 23, 2005, the complete subject matter of which is expressly hereby incorporated herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60683673 | May 2005 | US |
