Patent Publication Number: US-11660485-B2

Title: Fire suppression system

Description:
BACKGROUND 
     The invention relates generally to fire suppression systems designed to produce a foam-water mixture out of a discharge outlet. 
     SUMMARY 
     In many modern firefighting systems, a mixture is formed by injecting and metering foam concentrate into a water stream. Such systems are commonly used for fire suppression in industrial applications to combat fires in oil refineries, chemical plants, and other large facilities where highly flammable liquid materials are processed or stored. These fires are often fought by blanketing the flammable material with Class B foam. After use of the foam system there remains a significant volume of foam concentrate in the lines of the system. This concentrate must be removed from within the lines. Many foam concentrates congeal as they set for long periods of time, especially if air is present. This can lead to damage of mechanical components if not removed from the lines. 
     Larger industrial firefighting systems can hold as much as 5 to 15 gallons of foam concentrate in their plumbing manifolds. To remove it from the system, the foam concentrate is typically flushed through the system and pumped out of a discharge where it could undesirably enter the environment. Foam concentrates are also relatively expensive, costing between $20 and $40 per gallon of concentrate depending on brand and chemical makeup. 
     In one aspect, the invention provides a fire suppression system comprising a water supply system, a foam concentrate supply system, and a foam concentrate recovery system. The foam concentrate supply system includes a pipe segment. The foam concentrate supply system is fluidly connected with the water supply system to facilitate mixing of foam concentrate provided by the foam concentrate supply system and passing through the pipe segment with water provided by the water supply system. The foam concentrate recovery system includes a recovery pump fluidly connectable with the pipe segment of the foam concentrate supply system to facilitate the extraction of foam concentrate from the pipe segment. 
     In another independent aspect, the invention provides a method of operating a fire suppression system. The method comprises supplying water through a water supply system, supplying foam concentrate through a foam concentrate supply system including a foam tank and a foam concentrate supply line in fluid communication with the water supply system, mixing the water and the foam concentrate to form a foam-water mixture, exhausting the foam-water mixture from the fire suppression system, and recovering at least a portion of the foam concentrate from the foam concentrate supply line to the foam tank. 
     Independent aspects of the invention will become apparent by consideration of the detailed description, claims and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic view of a fire suppression system with injection of foam concentrate upstream of a water pump. 
         FIG.  2    is a schematic view of a second embodiment of a fire suppression system with injection of foam concentrate downstream of a water pump. 
         FIG.  3    is a schematic view of a third embodiment of a fire suppression system with a valve permitting injection of foam concentrate either upstream or downstream of a water pump. 
         FIG.  4    is a schematic view of a fourth embodiment of a fire suppression system similar to  FIG.  3    but including a first foam tank and a second foam tank. 
         FIG.  5    is a schematic view of a fifth embodiment of a fire suppression system similar to  FIG.  4    but including first and second vent valves and first and second recovery valves. 
         FIG.  6    is a schematic view of the fire suppression system of  FIG.  1    as applied in a vehicle. 
         FIG.  7    is a schematic view of the fire suppression system of  FIG.  1    as applied in a building. 
         FIG.  8    is a schematic view of the fire suppression system of  FIG.  1    in a supply mode and including arrows illustrating the flow of fluid. 
         FIG.  9    is a schematic view of the fire suppression system of  FIG.  1    in a recovery mode and including arrows illustrating the flow of fluid. 
         FIG.  10    is a schematic view of the fire suppression system of  FIG.  1    in a flushing mode and including arrows illustrating the flow of fluid. 
         FIG.  11    is a schematic view of the fire suppression system of  FIG.  1    in a circulation mode and including arrows illustrating the flow of fluid. 
     
    
    
     DETAILED DESCRIPTION 
     Before any embodiments of the present invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. 
       FIG.  1    illustrates a fire suppression system  10  capable of distributing a foam-water mixture in a supply mode, recovering a portion of residual foam concentrate from within the system  10  in a recovery mode, and flushing the remainder of residual foam concentrate from the system  10  in a flushing mode. Broadly speaking, the fire suppression system  10  shown in  FIG.  1    is a simple form of the invention, while the embodiments of the system  10  shown in  FIGS.  2 - 5    illustrate additional features of the invention.  FIGS.  6  and  7    illustrate the system  10  as applied in an apparatus  14  such as a fire truck  18  and a building  22  respectively. Other applications of the system  10  are possible.  FIGS.  8 - 10    illustrate the flow of fluid in the supply mode, recovery mode, and flushing mode, respectively, with regard to the fire suppression system  10  shown in  FIG.  1   . 
       FIG.  1    illustrates the fire suppression system  10  including a water supply system  26 , a foam concentrate supply system  30 , and a foam concentrate recovery system  34 . The illustrated water supply system  26  includes a water pump  38  and a water supply line  42 . The water supply line  42  receives water from at least one of a water tank  46  and an external water source  50 . 
     The illustrated foam concentrate supply system  30  includes a foam pump  54  and a foam concentrate supply line  58 . The foam concentrate supply system  30  receives foam concentrate from at least one of a foam tank  62  and an external foam source  66 . The foam concentrate supply line  58  is fluidly connected with the water supply system  26  upstream of the water pump  38 . This fluid connection facilitates mixing of foam concentrate provided by the foam concentrate supply system  30  with water provided by the water supply system  26 . 
     The foam concentrate recovery system  34  includes a recovery pump  70  and a recovery line  74 . The recovery line  74  fluidly couples the foam tank  62  to the foam concentrate supply system  30 . This fluid connection facilitates the extraction of foam concentrate from at least a portion of the foam concentrate supply system  30  and the recovery of the foam concentrate to the foam tank  62 . 
     With reference to  FIGS.  1  and  8   , the fire suppression system  10  distributes the foam-water mixture in the supply mode. In the illustrated supply mode, water flows at atmospheric pressure from the water tank  46  to a tank-to-pump valve  78  and a check valve  82  before entering the water pump  38 . Additionally or alternatively, water may flow from the external water source  50  to the water pump  38 . Foam concentrate flows from the foam tank  62  through a foam concentrate valve  86  and a check valve  90  before entering a foam pump  54 . Additionally or alternatively, foam concentrate may flow from the external foam source  66  to the foam pump  54 . Prior to entry into the foam pump  54 , the foam concentrate passes through a strainer  92 . Foam concentrate flows at pressure out of the foam pump  54 , through a foam concentrate flowmeter  94  and a metering valve  98 . The foam concentrate supply system  30  supplies foam concentrate in a first direction  99  away from the foam tank  62 , and opposite a second direction  100  that is towards the foam tank  62 . 
     The first suppression system  10  also includes a control system  102  that receives and transmits signals to control the operation of the system. The control system  102  is in electrical communication with various components of the fire suppression system  10 . For example, the flowmeter  94 , the metering valve  98 , the water pump  38 , the foam pump  54 , and the recovery pump  70  may receive and transmit data related to system operations to and from the control system  102 . Prime movers powering the water pump  38 , the foam pump  54 , and the recovery pump  70  may be adjusted to control the operating status of the water pump  38 , the foam pump  54 , and the recovery pump  70 . This allows for adjustment of the volumetric flow rate of both water and foam concentrate through the system  10 . The flowmeter  94  may serve to indicate the amount of flow of foam concentrate out of the foam pump  54 . The metering valve  98  may limit the flow of foam concentrate out of the foam pump  54 . Generally, the control system  102  is also responsible for opening and closing valves during shifting between operating modes, and any other related operations. 
     With continued reference to  FIGS.  1  and  8    and the supply mode, the illustrated foam concentrate supply line  58  supplies foam concentrate to the water supply line  42  upstream of the water pump  38 . A check valve  106  inhibits water from entering the foam concentrate supply line  58 . Water and foam are mixed upstream of the water pump  38 , and a foam-water mixture is passed into a manifold  110 , where the foam-water mixture is further homogenized. In this embodiment, there is a single manifold  110  in fluid communication with the water supply line  42  and the foam concentrate supply line  58 . The foam-water mixture is distributed from the manifold  110  to various discharge outlets  114 - 134  of the fire suppression system  10 . The foam-water mixture is passed through at least one of the discharge outlets  114 - 134  to eject from the manifold  110  and to be applied to a fire. The general flow of water, flow concentrate, and foam-water mixture is indicated by the dashed arrows in  FIG.  8   . 
     After the supply mode has been completed, the fire suppression system can be shifted to the recovery mode. The control system  102  may activate the shifting based on user input or other parameters. During shifting, the water pump  38  and foam pump  54  are deactivated, a vent valve  138  is opened, and a recovery valve  142  is opened. A check valve  144  inhibits backflow of fluid from the fire suppression system  10  to the surroundings through the vent valve  138 . The vent valve  138  is fluidly connected with the foam concentrate supply line  58  to facilitate recovery of foam concentrate from the foam concentrate supply line  58 . The vent valve  138  is in fluid communication with the surroundings of the fire suppression system  10 , and introduces recovery fluid (typically air) to the foam concentrate supply line  58 . The recovery valve  142  is in fluid communication between a portion of the foam concentrate supply system  30  and the foam tank  62 . The recovery valve  142  permits the passage of a portion of the foam concentrate in the foam concentrate supply system  30  back to the foam tank  62  in the second direction  100 . 
     With reference to  FIGS.  1  and  9    and the recovery mode, the recovery pump  70  is activated to pump foam concentrate from a portion of the foam concentrate supply line  58  through the flow switch  146  and a check valve  150  into the foam tank  62 . In the illustrated embodiment, foam concentrate is recovered from a pipe segment  101  of the foam concentrate supply line  58  from the vent valve  144  and through the strainer  92 . In the illustrated recovery mode, foam concentrate is recovered from the pipe segment  101  in the second direction  100 . The illustrated pipe segment  101  is located between the strainer  92  and the vent valve  138 . In other embodiments, the pipe segment  101  may include other portions of the fire suppression system  10 . During the recovery mode, movement of foam concentrate through the pipe segment  101  and the recovery line  74  is generally depicted by the dashed arrows in  FIG.  9   . At the end of the operation in the recovery mode, the flow switch  146  no longer senses concentrate flow and as a result sends a signal to the control system  102  to indicate the end of the operation in the recovery mode. Alternatively, another signal indicating the end of operation in the recovery mode may be suitable. Alternatively, manual shifting between modes may be suitable. 
     In response to the signal indicating the end of operation in the recovery mode, the fire suppression system  10  can be shifted from the recovery mode to the flushing mode. In shifting, the control system  102  sends signals to close the vent valve  138 , close the recovery valve  142 , close the foam concentrate valve  86 , and deactivate the recovery pump  70 . At least one of the discharge outlets  114 - 134  in fluid communication with the water supply system and foam concentrate supply system is opened to facilitate discharge of foam concentrate from the fire suppression system  10 . 
     With reference to  FIGS.  1  and  10   , in the flushing mode, a flush valve  154  is opened, the metering valve  98  is opened, and the foam pump  54  is activated. The flush valve  154  is located in a flush line  155  between the outlet of the water pump  38  and the inlet of the foam pump  54 . The opened flush valve  154  permits passage of water from the outlet of the water pump  38  to the foam concentrate supply line  58 . This passage of water collects any residual foam concentrate left in a portion of the foam concentrate supply line  58  after recovery. In flushing, water discharge from downstream of the water pump  38  flows through the flush valve  154  and the strainer  92  before entering the foam pump  54 . Water flows through the foam flowmeter  94 , flow metering valve  98 , and the check valve  106 . Water then flows through the water pump  38  into the manifold  110  where it flushes with clean water through at least one of the discharge outlets  114 - 134 . The general flow of water, flow concentrate, and foam-water mixture is indicated by the dashed arrows in  FIG.  10   . 
     In a second embodiment illustrated in  FIG.  2   , the foam concentrate supply line  58  supplies foam concentrate to the water supply line  42  downstream of the water pump  38 . In this configuration, pure water flows through the water pump  38 . As such, the possibility of congealment of foam concentrate in the water pump  38  is mitigated. This embodiment retains the main features of the embodiment illustrated in  FIG.  1   . Notably, the embodiment of  FIG.  2    can function in the supply mode, recovery mode, and flushing mode as in the embodiment of  FIG.  1   . In this embodiment, the foam-water mixture is passed into a first manifold  110 , and pure water is passed into a second manifold  158 . The second manifold  158  is in fluid communication with the water supply line  42 , and is not in fluid communication with the foam concentrate supply line  58 . As such, the fire suppression system  10  can, in the supply mode, discharge a foam-water mixture from the first manifold  110  and pure water from the second manifold  158 . Optionally, the fire suppression system  10  can, in the supply mode, simultaneously discharge a foam-water mixture from the first manifold  110  and pure water from the second manifold  158 . A check valve  160  inhibits backflow of the foam-water mixture towards the water supply system  26 . Both the first manifold  110  and the second manifold  158  can be flushed in the flushing mode. 
     In a third embodiment illustrated in  FIG.  3   , the foam concentrate supply line  58  includes a valve  162  capable of connecting the foam concentrate supply line  58  to the water supply line  42  upstream or downstream of the water pump  38 . In the illustrated embodiment, the valve  162  is a three-way valve  162 . The three-way valve  162  permits the fire suppression system  10  of  FIG.  3    to function as in the fire suppression system  10  of  FIG.  1    or  FIG.  2    based on the operation of the three-way valve  162 . In other words, the three-way valve  162  permits the foam concentrate supply line  58  to shift between a first position in which the foam concentrate supply line  58  supplies foam concentrate to the water supply system  26  upstream of the water pump  38  and a second position in which the foam concentrate supply line  58  supplies foam concentrate to the water supply system downstream of the water pump  38 . A check valve  164  is positioned between the three-way valve  162  and the water supply line  26  to inhibit backflow of water into the foam concentrate supply line  58 . The fire suppression system  10  of  FIG.  3    can function in the supply mode, the recovery mode, and the flushing mode as in the embodiment of  FIG.  1   . 
     In a fourth embodiment illustrated in  FIG.  4   , the fire suppression system  10  includes a first foam tank  62  and a second foam tank  166 . Additional valves are also positioned in both the foam concentrate supply line  58  and the recovery line  74  such that foam concentrate can be supplied and recovered from either one of the first foam tank  62  and the second foam tank  166 . As such, the foam recovery line  74  is capable of being shifted between a first position in which the recovery pump  70  extracts foam concentrate to the first tank  62  and a second position in which the recovery pump extracts foam concentrate to the second tank  166 . The additional valves on the supply line may include, but are not limited to a second foam tank-to-pump valve  170  and check valve  176  inhibiting backflow of fluid into the second foam tank  166 . The additional valves on the recovery line may include but are not limited to a valve  174  for selecting which tank  62 ,  166  foam concentrate will be recovered to, and a check valve  178  inhibiting backflow of foam concentrate towards the valve  174  from the second foam tank  166 . In the illustrated embodiment, the valve  174  is a three-way valve  174  capable of recovering foam concentrate to at least one of the first foam tank  62  and second foam tank  166 . 
     In the fourth embodiment of  FIG.  4   , the first foam tank  62  includes a first type of foam, for example Class A foam, and the second foam tank  166  includes a second type of foam, for example Class B foam. In such an embodiment, the fire suppression system  10  can be operated to supply and recover a given type of foam, flush the residual foam, and supply and recover the other type of foam. In other embodiments, the first foam tank  62  and the second foam tank  166  simply store the same classification of foam concentrate. 
     In a fifth embodiment illustrated in  FIG.  5   , the fire suppression system  10  includes the vent valve  138  and a second vent valve  182 . The second vent valve  182  is positioned in the foam concentrate supply line  58  at a location corresponding to a different potential pressure of the foam concentrate supply line  58  as the vent valve  138 . A check valve  186  is positioned between the second vent valve  182  and the foam concentrate supply line  58  to inhibit flow of fluid from the foam concentrate supply line  58  to the surroundings of the fire suppression system  10 . As illustrated in  FIG.  5   , the vent valve  138  is at a relatively high potential pressure (i.e., downstream of the foam pump  54 ), and the second vent valve  182  is at a relatively low potential pressure (i.e., upstream of the foam pump  54 ). This permits the second vent valve  182  to introduce fluid (e.g., air) at a different potential pressure than the vent valve  138 . In this embodiment, shifting the fire suppression system  10  from the supply mode to the recovery mode can include opening the second vent valve  182 . 
     With continued reference to  FIG.  5   , the fire suppression system  10  further includes a second recovery valve  190 . The second recovery valve  190  is positioned in the recovery line  74  at a location corresponding to a different circuit of the recovery line  74  and the foam concentrate supply line  58 . Foam concentrate is allowed to be recovered independently from separate sections of the foam concentrate supply line  58  and the recovery line  74 . This permits the recovery valve  142  and the second recovery valve  190  to allow fluid communication between the supply line  58  and the foam recovery line  74  and one of the foam tanks  62 ,  166  at multiple low points along the foam concentrate supply line  58  and the recovery line  74  that do not allow drainage from the low point. 
     The fire suppression system  10  is capable of operating in a circulation mode ( FIG.  11   ) that circulates foam concentrate to promote mixing of the foam concentrate and hinder the congealment of foam concentrate in a portion of the foam supply system and a portion of the foam recovery system. The dashed arrows in  FIG.  11    indicate the flow of fluid. As a periodic maintenance measure, the recovery pump  70  is activated with the foam concentrate valve  86  and the recovery valve  142  both open and the metering valve  98  and flush valve  154  closed. Foam concentrate from the foam concentrate tank  62  flows through the foam concentrate valve  86 , the check valve  90 , at least a portion of the foam concentrate supply line  58 , the recovery valve  142 , the recovery pump  70 , the flow switch  146 , the recovery line  74 , and the check valve  150 . After passing through the check valve  150 , foam concentrate is then returned to the foam tank  62 . After circulating foam concentrate through the foam supply line  58  and the recovery line  74 , the fire suppression system  10  can be shifted to the recovery mode as illustrated in  FIG.  9    and described above, and then the flushing mode as illustrated in  FIG.  10    and described above. 
     One or more independent features and/or advantages of the invention may be set forth in the following claims.