Abstract:
A fluid flow detector test system includes a flow conduit and a pump for providing a test fluid flow at the detector. A test unit includes a programmed processor coupled to the pump by a drive circuit such as a solid state switch or a relay. The detector&#39;s output is coupled to an input port of the processor. To initiate a test, executable instructions, coupled to the processor, enable the processor to energize the pump, creating a test fluid flow. The processor senses the detector&#39;s output to evaluate its test performance. An alarm system having a plurality of detectors can include a plurality of such test systems, one coupled to each detector.

Description:
FIELD OF THE INVENTION 
     The invention pertains to fire alarm systems. More particularly, the invention pertains to testable flow detection systems wherein the presence of flow is often indicative of an alarm or fire condition. 
     BACKGROUND OF THE INVENTION 
     One form of known fire alarm system includes waterflow conduits or pipes which are coupled to sprinkler heads. The sprinkler heads contain a heat sensitive material. In the presence of elevated temperature, such as caused by a fire, the material in the sprinkler heads melts and water, under pressure in the pipes or conduits, sprays from the sprinkler heads to suppress the fire in the adjacent area. 
     It is also known to incorporate flow detectors into the conduits of such suppression systems. Examples of such flow detectors can be found in Merchant U.S. Pat. No. 4,782,333 as well as Griess U.S. Pat. No. 4,791,414, both of which are assigned to the assignee hereof. Such flow detectors conventionally include a sensor which extends into the respective pipe or conduit and which is moved from a quiescent position to an active position in response to a waterflow in the pipe or conduit. This movement produces an output signal indicative of the flow of water which is also associated with the presence of a fire condition. 
     A problem has been recognized with respect to such flow detectors in that they usually remain in a quiescent state for long periods of time due to the absence of an alarm or fire condition. However, such detectors are expected to function properly in the presence of flow, which is of course indicative of the presence of a fire or an alarm condition, notwithstanding long intervals which could be months or years without any fire conditions. 
     It would be desirable therefore to be able to provide a test system for flow detectors which could be used to conduct a variety of different tests of the respective detector on a routine basis and in the absence of an emergency or fire condition. Preferably, it would be possible to interconnect the units for a plurality of detectors such that groups of detectors could be tested at essentially the same time. 
     SUMMARY OF THE INVENTION 
     A test unit for a fluid flow detector includes a programmed processor which executes a set of preloaded instructions for carrying out one or more tests of an associate flow detector. An auxiliary water pump can be used to provide a flow of test fluid to actuate the detector. Output drive circuitry is coupled between the programmed processor and the pump such that the pump operates under the control of the programmed processor. Output drive circuitry can be implemented using relays or solid state drive circuits. 
     An input port of the processor can be coupled to the signal output port from the respective detector. The processor can include a second input port, for example from another identical test unit, when the test units are grouped together with a group of flow detectors. The test units can also include a manually operable control element, such as a multi-position key switch or keyboard for purposes of carrying out locally controlled tests. 
     In one instance, the executable instructions in the processor, in connection with a timer or a real time clock included in the processor, can activate the output circuitry periodically, for example every several days, for a brief period of time, on the order of 300 milliseconds, for purposes of minimizing pump impeller junk or crud buildup. In another mode, the processor can activate the circuitry continuously to conduct a test of the respective detector. 
     In a group test mode, placing one of the test units in the group test mode transmits a signal to each of the other units in the group whereupon all of the units in the group energize their respective water pumps and sense test indicating signals from the respective detectors substantially at the same time. Alternately, the units can function sequentially with each member of the group carrying out its test sequence depending upon its position in the group. 
     Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings. 
    
    
     BRIEF DESCRIPTIONS OF THE DRAWINGS 
     FIG. 1 is an over-all block diagram of an alarm system in accordance with the present invention; 
     FIG. 2 is a block diagram illustrating details of the test units of FIG. 1; and 
     FIG. 3 is a block diagram illustrating an alternate configuration of the system of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     While this invention is susceptible of embodiment in many different forms, there are shown in the drawing and will be described herein in detail specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated. 
     FIG. 1 illustrates a system  10  which embodies the present invention. In FIG. 1, waterflow conduits C 1 , C 2  . . . Cn of a type that might be found in a building fire alarm system are each connected to a respective sprinkler head (not shown). As is conventional, in the presence of heat, the respective sprinkler head or heads become activated whereupon fluid in each of the respective conduits Ci flows under pressure, indicated at F 1 , F 2  . . . Fn through the activated sprinkler head to suppress the fire in the respective region. 
     FIG. 1 also illustrates a plurality of flow detectors  12 - 1 ,  12 - 2  . . .  12 n. Each of the flow detectors  12 - i  is operatively coupled to a respective conduit Ci to detect a fluid flow Fi therein. An indication of this fluid flow can be provided at a respective output port, on lines  14 - 1 ,  14 - 2  . . .  14 -n in the form of an electrical signal. For example, in a no flow condition, a normally open contact or a normally closed contact closure can be provided with a respective change of state produced by the flow Fi. 
     For purposes of maintenance each detector, such as detector  12 - i,  has associated with it a respective test unit  20 - i.  Associated with each respective test unit  20 - i  is a pump  22 - i  electrically coupled to the respective test unit  20 - i.  Each of the pumps can draw fluid from and return fluid to the respective conduit C-i to create test flow Fit by means of a respective test flow input conduit  24 - i  and a respective test flow output conduit  26 - i  via an output  14 ′- i.    
     The respective output signal on the line  14 - i  can in turn be coupled directly to the respective test unit  20 - i.  Alternately the output signal can be coupled to a system control unit indicated generally at  16  via an output  14 ′- i . Control unit  16  in turn can respond to the detected fluid flow by energizing alarm output devices  16   a.    
     Each of the test units  20 - i  incorporates a manually operable control element  30 - i.  This element might be a multi-position key switch, for example, or a keypad or card reader. Using the control element  30 - i  the respective test unit  20 - i  can be placed into an active state whereupon the respective pump  22 - i  will be activated. 
     Hence, in the active state, the respective test unit,  20 - i  can energize pump  22 - i  and produce a flow of fluid Fit in the vicinity of the respective flow detector  12 - i.  The detector  12 - i  will in turn, upon detecting the test flow, output a test signal from its output port on line  14 - i  which is in turn sensed by test unit  20 - i.    
     One output from the respective detector  12 - i  can be coupled to the respective test unit  20 - i.  The other can be directly coupled to the control element  16  as required. 
     A selected test mode can be entered at unit  12 - i  by a manual input at the respective control element  30 - i.  Alternately control unit  16  can issue an appropriate command or commands to the respective test unit. 
     In addition to individually actuating each of the units  20 - i,  group testing can be implemented. Test units can be coupled together, based on groups of detectors, indicated by signal paths  32 - 1  . . .  32 - n− 1. In such an instance, the system will support a mode of multiple unit, group, activation. 
     A single control signal, from, for example, element  30 - 1  or control unit  16  can activate test unit  20 - 1  to carry out a selected type of test. This activation can in turn be coupled to test unit  20 - 2  and on to test unit  20 - n,  assuming they are in the same group, causing those respective units to carry out the same type of test in response to a single initiating control signal. 
     Various types of test unit outputs can be initiated. For example, the respective test unit can actuate the respective pump, for example once a week, for a brief period of time such three hundred milliseconds. In another mode, the respective test unit can be placed into a self-test mode whereupon the respective pump will be energized continuously until the test unit is taken out of that mode. Finally, a group test can be carried out wherein when a selected test unit, such as unit  20 - i  is activated, those units to which the activated test unit is coupled, via signals  32 - i  will also be tested in the same fashion. For example, in group test, a continuous test output can, in a preferred embodiment, be produced until the unit is released manually. 
     FIG. 2 illustrates in greater detail, in block diagram form, the structure of respective test units such as  20 - i  and  20 - i+ 1. Elements in FIG. 2 which are common with those in FIG. 1 have been assigned a corresponding identification numeral. 
     The following discussion of test unit  20 - i  is applicable to the remaining test units so only unit  20 - i  needs to be discussed. The test unit  20 - i  includes a programmable processor, such as a microprocessor,  40 - i.  An input port of the processor  40 - i,  indicated generally at  42 - i,  is coupled to the output port of the respective flow detector  12 - i.    
     An output port  44 - i  is coupled to the respective water pump  22 - i.  Output drive circuitry, which could be implemented as either a relay or a solid state switch, indicated generally at  46 - i  provides interface circuitry between processor  40 - i  and waterpump  22 - i.    
     Coupled to processor  40 - i  is a storage unit  48 - i  which could be integral therewith wherein instructions executable by processor  40 - i  are stored. Storage units can be implemented as RAM, ROM, EEPROM or the like without limitation. Execution of these instructions enables processor  40 - i  to carry out different processing sequences based on the setting of input control element  30 - i,  or, based on signals received from another test unit on communication lines  32 -( i− 1). 
     An optical isolator  50 - i  can be interposed between the communication lines  32 -( i− 1) and processor  40 - i  for isolation purposes. Additionally, output drive circuitry  52 - i  can be provided between processor  40 - i  and output communication lines  32 - i.  This circuitry is in turn coupled to test unit  20 -( i+ 1). 
     It will be understood that a variety of control programs can be loaded into the storage unit or memory  48 - i  without departing from the spirit and scope of the present invention. However, irrespective of how implemented, such control programs will enable the respective test unit  20 - i  to energize the respective pump  22 - i  and receive or sense signals from the respective detector  12 - i  in accordance with the selected operational or test mode. 
     FIG. 3 illustrates an alternate implementation, in block diagram form, of system  10  of FIG.  1 . Elements in FIG. 3 which are common with those in FIGS. 1 or  2  have been assigned a corresponding identification number. 
     Unlike the system of FIG. 2, in the system of FIG. 3, test units such as  20 ′ i  and  20 ′ i+ 1, when in a common group, can be coupled together using a two wire interconnect  33 - i.  In each instance, a respective processor such as  40 ′- i and  40 ′- i+ 1 has a group test input port connected to the two wire interconnect system  33 - i.  In this embodiment, all members of one group would be coupled to interconnect  33 - i  as illustrated in FIG.  3 . Setting a respective test unit  20 - i  in the group into a group test mode using manual input  30 - i  will cause an appropriate signal to be transmitted via the two wire interconnect  33 - i  to all group members. As a result, group members will carry out an essentially simultaneous group test of the respective water flow detector, such as the detector  12 - i.    
     It will be understood that as an alternate to initiating the group test mode using the manual input device  30 - i,  a command can be initiated from the control element  16  to carry out a group test. In this instance, a specific group would be identified by the control element  16 . The test units  20 - i  in each group would recognize that they are part of the specified group for carrying out the required test. 
     From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.