Patent Description:
Liquid fire suppression agents have been used for decades. Although some agents such as hydrofluorocarbon (HFC) (e.g. Halon <NUM> (bromotrifluoromethane) and HFC-227ea (heptafluoropropane)) are in disfavor due to environmental concerns, replacements are readily commercially available, such as a fluoroketone formulated as dodecafluoro-<NUM>-methylpentan-<NUM>-one (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>-nonafluoro-<NUM>-(trifluoromethyl)-<NUM>-pentanone) (CF<NUM>CF<NUM>C(O)CF(CF<NUM>)<NUM>) (ASHRAE nomenclature FK-<NUM>-<NUM>-<NUM>). Such agents are typically used with a pressurant/propellant such as N<NUM>. Kidde-Fenwal, Inc. of Ashland, Massachusetts manufactures an exemplary fire suppression system, the Kidde® ADS™. Other suppressant agents and pressurants/propellants may be used in fire suppression systems as necessary to meet desired fire suppression capabilities.

Typically such agents are stored as a liquid in one or more metal tanks (e.g., steel tanks having a cylindrical centerbody and domed ends, although other shapes and materials are also known in the art). A tank is typically positioned with its axis vertical so that one end is an upper end or top and the other a lower end or base. The upper end typically has a number of ports with fittings (e.g., threaded fittings). Typically a large center port receives a discharge assembly. The discharge assembly may include a fitting portion mated to the tank fitting and an external valve (e.g., automatically controllable via a control system). A discharge conduit (also known as a siphon tube or dip tube) extends downward into the tank and typically has an open lower end near the bottom of the tank. In facility configurations requiring multiple tanks, the tanks may be connected to a suppression system serially, independently, or in distributed locations in different configurations, and may be co-located or distributed throughout a facility. The suppression system includes piping from the tank(s) to endpoints such as discharge nozzles. Various pressure regulators and controllable valves may be located along the piping to provide selective discharge of suppressants at locations of fire.

Due to their low heat of evaporation and high vapor pressure (e.g., relative to water), typical liquid fire suppression agents will rapidly vaporize at discharge from the nozzle outlets and thus be delivered as vapor.

If the discharge valve is opened, pressure in the tank headspace (e.g., from the pressurant/propellant noted above) is sufficient to drive liquid suppressant up through the discharge conduit and out of the tank. Pre-use, the surface level of liquid in the tank will typically be well into the upper half of the tank. The exact position will depend on factors including the nature of the suppressant, the nature of the pressurant/propellant (e.g. composition and whether internally or externally located), and the application.

It is necessary to at least occasionally measure the fluid level in the tank (e.g., safety regulations typically require semi-annual inspection including verification of agent amount). To do this without venting the tank, several liquid level measurement systems have been proposed. A number of these systems make use of an additional vertically-extending conduit mounted to an additional port in the tank upper end. Typically, the tanks may be provided with multiple smaller off-center ports (e.g., with internally-threaded fittings) in addition to the center port. These ports may serve for various functions. An exemplary such liquid level sensing system has a fitting mounted to one of those additional port fittings with a conduit (e.g., metal tube) extending vertically down toward the base of the tank. Unlike the discharge conduit, the lower end of this liquid level sensing tube is closed so that the interior of the liquid level sensing tube is sealed relative to the surrounding interior of the tank. A float may surround the liquid level sensing tube. The float may be magnetized. The float may magnetically interact with a member movable within the tube to in turn provide indication of the liquid level.

In one basic example of such a liquid level sensing system, the liquid level sensing fitting, in turn, has a removable cap or plug providing access to the upper end of the tube. A magnetic weight at the end of a measuring tape, string, or other device, may be located in the tube. The magnetic weight will interact with the float to be held at the same level as the float and thus at the level of the surface of liquid in the tank. This allows the level of the surface of liquid in the tank to be measured relative to the liquid level sensing fitting and thus relative to any other reference on the tank. Such measurements are typically taken periodically manually by a person assigned to the task. In one example where the weight and measuring tape are already in the tube, the end of the tape opposite the weight may be connected to the removable cap or plug. The user may open the cap or plug and pull to take up slack in the measuring tape. The user may take a reading with the tape to determine the liquid level of the tank.

Yet more complex systems are automated with the magnetic weight permanently within the tube and its vertical position electronically measured. Yet other systems involve capacitive measurements between inner and outer tubes.

Monitoring of the fire suppression system is typically performed by a fire control panel adjacent the tank(s). The fire control panel may be coupled to one or more sensors or switches on each tank. For example, sensors may include pressure sensors and liquid level sensors and switches may include the control head placement sensor. Exemplary pressure sensors may effectively be switches in that they are set to open or close a circuit at a threshold pressure. The threshold may be set when the fire suppression system is manufactured.

The control head is part of the discharge assembly and actuates a discharge valve on the tank. An exemplary control head placement sensor is disclosed in International Application Pub. No. <CIT>, <CIT>, of UTC FIRE & SECURITY CORPORATION and inventor Thomas Kjellman, and entitled "EXTERNALLY MOUNTED DEVICE FOR THE SUPERVISION OF A FIRE SUPPRESSION SYSTEM". The control head placement sensor is mounted to the tank and has a switch which is depressed by the presence of a control head of the discharge assembly. The switch may be a normally closed switch or a normally open switch.

Additionally, some stock switches are dual output switches that have three connections/conductors/poles: a common connection ("common"); a normally closed (NC) connection; and a normally open (NO) connection. When such a switch is undepressed, there is no continuity between the normally open pole and the common but there is continuity between the normally closed pole and the common. When the switch is depressed, however, there is conductivity between the normally open pole and common while lacking continuity between the normally closed pole and the common. Some of the normally closed poles and normally open poles may be connected to the fire control panel; whereas, the other may be disconnected from any external device.

The fire control panel monitors and controls the fire suppression system. It collects sensor input from detectors such as smoke sensors and user input devices such as pull boxes. It analyzes sensor inputs to determine if a fault, warning, or alarm condition is present. It communicates this system status locally (e.g., display or status light) and may communicate this status remotely (e.g., via a telephone line or Ethernet or cellular to a remote monitoring station (e.g., computer at a third party monitoring company or fire department)). Depending on the determined status condition (e.g., fault, warning, alarm), the fire control panel controls appropriate connected devices. For example, during alarm condition, the fire control panel may activate notification devices such as strobes and horns and initiate suppressant discharge by activating control heads connected to the suppressant tanks.

The construction and operational parameters of the fire control panels are subject to numerous constraints. For example, there may be code requirements and industry standard requirements (e.g., requirements for a listing by Underwriters Laboratory (UL) or other certification body). In addition to restricting construction and operation of fire control panels, generally, such codes, standards, and approval requirements also affect any updates or retrofits/modifications. For example, if a manufacturer wants to sell an updated version of an approved fire control panel with new constructional details or operational features, the updated version may be subject to requirements for re-approval/re-certification. Similarly, an in-field modification of an existing fire control panel may require such re-approval/re-certification. The in-field modification may also require expensive inspection.

<CIT> discloses a fire suppression system for a clean room, the fire suppression system having features of the type set out in the pre-amble of claim <NUM>.

The present invention provides a fire suppression system comprising a tank unit. The tank unit has a tank body having a first port and an interior for storing at least one of fire suppressant and driver gas. A discharge assembly is mounted to the first port and comprises: a discharge valve; and a first monitoring switch or sensor having a normally closed output and a normally open output. A first monitoring system is coupled to one of the normally closed output and the normally open output. A second monitoring system is coupled to the other of the normally closed output and the normally open output.

Optionally, the fire suppression system further comprises a hazard sensor and the first monitoring system comprises an input from the hazard sensor.

Optionally, the hazard sensor comprises a smoke detector.

Optionally, the fire suppression system further comprises a pull box and the first monitoring system comprises an input from the pull box.

Optionally, the discharge assembly comprises a control head and the first monitoring system comprises a control output to the control head.

Optionally, the tank unit further comprises a liquid level sensor not connected to the first monitoring system and the second monitoring system comprises an input from the liquid level sensor.

Optionally, the second monitoring system comprises: a radio.

Optionally, the first monitoring switch or sensor is selected from the group consisting of pressure switches or sensors and control head placement switches or sensors.

Optionally, the system further comprises at least one sensor coupled to the second monitoring system but not coupled to the first monitoring system.

Optionally, the at least one tank unit is a plurality of tank units and the first monitoring system is a single first monitoring system coupled to the plurality of tank units.

Optionally, the second monitoring system comprises, for each of the plurality of tank units, a respective electronics module coupled to the other of the normally closed output and the normally open output and having a radio.

Optionally, the electronics modules are configured to communicate with each other.

Optionally, the second monitoring system comprises a hand held device in communication with the respective radios of each electronics module.

Optionally, the electronics modules are configured to each store status data from all the electronics modules at predetermined times and the electronics modules are configured so a user of the hand held device may manually activate any of the electronics modules to communicate said data to the hand held device.

Viewed from another aspect the invention provides a method for using the system that comprises: with the first monitoring system, receiving input from one or more hazard sensors or pull boxes; and with the second monitoring system, communicating status via a radio.

Optionally, the method further comprises, with the first monitoring system, controlling suppressant delivery.

Optionally, the first monitoring system communicates with a remote monitoring system.

Optionally, the second monitoring system communicates said status to a hand held device which, in turn, communicates with the remote monitoring system.

A method for manufacturing the system comprises, with the tank containing at least one of fire suppressant and driver gas, installing the second monitoring system.

<FIG> shows a fire suppression system <NUM>. The system includes a suppressant source <NUM> and one or more flowpaths <NUM> to one or more protected locations (also known as "hazards") <NUM>. The flowpath(s) <NUM> pass from the source <NUM> to outlets <NUM> at the location(s) <NUM>. The exemplary outlets <NUM> are outlets of discharge nozzles <NUM> for discharging discharge streams or flows <NUM>.

The exemplary source <NUM> includes multiple tanks <NUM> of suppressant (agent). The exemplary configuration is a remote driver configuration where the pressurant for each agent tank is remote of that tank. An exemplary agent is a liquid agent and an exemplary pressurant is nitrogen and/or argon. <FIG> shows each agent tank respectively associated with a driver or pressurant tank <NUM>, <NUM> in a unit <NUM>, <NUM>, <NUM>, <NUM>. However in alternative situations either the agent itself is also a pressurant (e.g., inert gas systems) or the pressurant is stored in the headspace of the agent tank. The exemplary configuration includes three kinds of units. Unit <NUM> serves as the primary unit. Its driver tank <NUM> is equipped with an electric control head <NUM> (<FIG>) controlled by the fire control panel <NUM> via a line <NUM>. In the illustrated example, an optional reserve unit, <NUM> (<FIG>) also has a driver tank with an electric control head <NUM> controlled by the fire control panel (via its own line <NUM>).

To handle situations where a single suppressant tank is insufficient to protect hazard locations <NUM>, the suppressant source <NUM> contains additional, secondary units <NUM>, <NUM>. These secondary units are each equipped with a pneumatic control head <NUM> (<FIG>) connected in-series to each other and to the primary suppression unit <NUM> or the reserve suppression unit <NUM>. The illustrated example has a series connection along a flowpath <NUM> from the primary unit <NUM> to the first secondary unit <NUM> and then to the second secondary unit <NUM> via conduits (e.g., hoses) <NUM>.

The system <NUM> may further include a reserve unit <NUM> which may be controlled independently of the primary and secondary units. This may be used to address re-ignition situations or situations where the primary and secondary units are insufficient to even temporarily extinguish a hazardous condition. The reserve unit may itself be a primary unit having one or more associated secondary units.

As shown in <FIG>, the respective suppressant tanks <NUM> and driver tanks <NUM>, <NUM> each have a valve <NUM>, <NUM> mounted to a fitting <NUM>, <NUM> of a tank body <NUM>, <NUM>. A pressurant flowpath <NUM> extends through a driver conduit <NUM> (e.g., hose) between the associated valves <NUM>, <NUM>.

The flowpaths <NUM> (<FIG>) comprise respective legs <NUM> though conduits <NUM> (<FIG>, e.g., hoses) from the agent tank valve <NUM> to a supply manifold <NUM>. Valves <NUM> (e.g., check valves) may be located along the legs <NUM> upstream of a manifold conduit <NUM> (e.g., metal pipe).

The flowpaths <NUM> comprise respective legs <NUM> though conduits <NUM> (<FIG>, e.g., metal pipe) from the manifold conduit <NUM> to the locations <NUM> One or more valves <NUM> may selectively permit or block flow along the flowpath legs <NUM>. The exemplary valves <NUM> are solenoid valves controlled by a fire control panel <NUM>. Exemplary solenoid valves <NUM> are piloted valves piloted by a gas (e.g., nitrogen) from a pilot tank <NUM> having a discharge valve <NUM> controlled by the fire control panel.

<FIG> also shows a pressure switch <NUM>. There may be such pressure switches exposed to the respective flowpaths <NUM> and each may have one or more functions. The pressure switch is activated upon pressurization of the associated flowpath <NUM>. A first function is to turn on or turn off electrical appliances that would respectively assist or impede the effectiveness of the suppression system. Examples of the electrical appliances <NUM> include, but are not limited to speakers and sirens to warn occupants located in spaces <NUM> of imminent suppressant release, air handling units supplying and retrieving air from the spaces <NUM> (e.g., the switch might turn off HVAC components to limit air inflow to the affected space and keep suppressant in the space), door and window actuators (e.g., the switch might close such doors and windows to limit air introduction and suppressant loss) and related appliances (e.g., louvers). The pressure switch <NUM> may also be connected to the fire control panel <NUM> and communicate its status information such as ready, activated or malfunction.

<FIG> also shows, at each location <NUM>, one or more sensors/detectors <NUM> (e.g., smoke detectors, heat detectors, and the like) and one or more pull boxes. These may be hardwired to the fire control panel. Referring to <FIG> and <FIG> together, exemplary system activation involves the fire control panel receiving input (e.g., simple switched input or a digital or analog input) from a sensor/detector <NUM> or pull box <NUM>. The fire control panel then activates the primary unit <NUM>. To do so, the fire control panel sends a signal (e.g., applies power via the associated line <NUM>) to the primary unit <NUM> electric control head <NUM> which, in turn actuates (opens) the associated valve <NUM>. Pressurant stored in the primary unit driver passes through the associated conduit <NUM> and pushes the primary unit's suppressant through the conduit <NUM> into the distribution piping <NUM>. Simultaneously, the pressure from the primary unit's driver is also transmitted through the first conduit <NUM> to the first secondary unit's pneumatic control head <NUM>. This pressure opens the first secondary unit's valve <NUM> causing further release of the suppressant into the distribution piping and further activation of additional secondary unit(s) via the remaining sequential conduits <NUM>. When releasing pressurant, the fire control panel may issue appropriate control signals to one or more local notification devices <NUM> such as speakers (for audible warnings such as alarms or prerecorded or synthesized voice warnings), other audio sources such as horns, and/or visual sources such as strobes or other lights to warn personnel in the area of a hazardous condition. The fire control panel may also issue an alarm signal to a remote notification station such as monitoring center or fire station (<NUM> via communications link <NUM> in <FIG> discussed below).

However in alternative (integrated) situations either the agent itself is also a pressurant (e.g., inert gas systems) or the pressurant is stored in the headspace of the agent tank and the driver tanks are not required. In that case, the electronic control head(s) <NUM> and pneumatic control heads <NUM> are located on the corresponding suppressant tanks.

<FIG> further shows one or more of the suppressant tanks and driver tanks as having a control head placement switch sensor <NUM> (e.g. as in <CIT>), which is mounted to the tank and incorporates a switch which is depressed by the presence of a control head on the valve <NUM> (discharge valve assembly) (<FIG>). In remote driver examples, the control head placement switch sensor <NUM> may be only on the drivers; in integrated examples it is on the suppressant tanks. In one example, the control head placement switch sensors may be mounted on the primary unit tank and the reserve unit tank, but not the secondary unit tanks. The exemplary switch sensors are further connected on a common circuit loop <NUM> either in series or in parallel and wired to the fire control panel for supervisory monitoring of fault conditions. The supervisory circuit within the fire control panel interrogates the status of the placement switch sensors by measuring circuit resistance, for example. Change in state of the placement switch sensors (for example connected to the control head or disconnected) results in, for example, change in the circuit resistance detected by the control panel. The panel issues the appropriate fault condition warning through its internal display upon detecting that any one of the placement switch sensors indicates loss of control head connectivity to the body of valve body <NUM>, <NUM>.

The exemplary suppression system <NUM> has pressure switch sensors <NUM> (<FIG>, e.g., diaphragm-type mechanical switch), mounted to primary, reserve and secondary tanks (either or both suppressant and driver tanks). These pressure switch sensors are further connected together on a common circuit loop <NUM> and wired to the control panel for supervisory monitoring. The supervisory circuit within the control panel interrogates the status of the pressure switch sensors by measuring circuit resistance for example. Change in state of the pressure switch sensors (for example loss of pressure within the tank) results in, for example, change in the circuit resistance detected by the control panel. The panel issues the appropriate fault condition warning through its internal display <NUM> upon detecting that any one of the pressure switch sensors indicates change of pressure within the tanks. The panel <NUM> issues warnings indicative of the disconnected control head or pressure loss within any given tank. Within the typical system, further identification of the specific tank affected with disconnected control head or pressure loss in not possible. Therefore, each individual tank requires independent inspection to localize the issue and take appropriate corrective action such as re-installation of the control head or re-pressurizing of the tank. This is problematic and time consuming for large installations containing tens and hundreds of tanks.

The fire control panel <NUM> is schematically represented in <FIG>. A user interface driver <NUM> supports display (<NUM> above), keyboard, and related functions. The main processing unit <NUM> (e.g., having a microprocessor and memory/storage (e.g., solid state)) receives information from all input circuits, performs the system status determination and issues instructions to control circuits and the display. The detection loop circuit <NUM> receives status information from all the system input devices such as smoke sensors, heat sensors, and user pull boxes and relays this information to the processing unit. The control head monitor supervisory circuit <NUM>, receives status information from the control head switch sensors. Similarly, the pressure switch sensor supervisory circuit <NUM>, receives status information from the pressure switch sensors. Both supervisory circuits relay this information to the main processing unit. The control circuits 310A and 310B (<FIG>) appropriately energize control heads <NUM> and thus the associated valves <NUM> and <NUM> as to initiate the system response based on signals received from the main processing unit. Similarly, the notification control circuit <NUM>, activates notification devices such as voice warnings, strobes and horns based on signals received from the main processing unit. The control panel may also contain communication module <NUM> allowing the system status to be monitored remotely such as at a monitoring station. The communication module <NUM> interface may be an Ethernet connection for connection via router/modem to the internet or may comprise a connection to a telephone landline, or may comprise a wireless telephone (e.g., cellular) connection. The exemplary fire control panel may contain additional circuits and modules to receive additional input and provide additional output depending on type of installation and system complexity.

As so far described, the system is merely one example of a baseline system to which further modifications may be made. An exemplary modified system discussed below adds a parallel monitoring functionality to that already provided by the baseline. The exemplary modified system makes use of dual output sensors or switches (collectively "switches" unless indicated to the contrary) if present or provides dual output switches for parallel monitoring of a given switch. The modified system may add monitoring functions (and associated switches) not present in the baseline. In one example, the added functionality is a liquid level monitoring functionality using a liquid level sensor <NUM> (<FIG>, e.g., a magnetic float sensor) mounted to a fitting <NUM> on the suppressant tank. In another example, the added functionality is a temperature sensing functionality using a thermistor <NUM> (<FIG>) collocated with the liquid level sensor.

<FIG> shows the modified system as having an additional monitor module <NUM> (also see <FIG> schematic discussed below) associated with each unit <NUM>, <NUM>, <NUM>, <NUM>. Each monitor module <NUM> is connected to the associated control head placement switch sensor(s) <NUM>, pressure switch sensor <NUM>, and level sensor <NUM> through wired connections <NUM>, <NUM>, <NUM>, respectively. The connection <NUM> from the control head placement sensors and the connection <NUM> from pressure switch sensors to the control panel <NUM> are independent of the respective associated connections <NUM> and <NUM> to the monitor module <NUM>.

As is discussed further below, each monitor module <NUM> may include visual output devices such as a display <NUM> (<FIG>, e.g., LCD or LED) and one or more status indicator lights <NUM>, <NUM> (e.g., colored LED). For example, the display displays information such as type, quantity and temperature of an agent present within the tank (e.g., "FM-<NUM>; <NUM> lbs. ; 78F"), while the indicator lights indicate status of the control head placement sensor and the pressure switch sensor (e.g., green light indicating connected control head and appropriately pressurized tank; red light indicating disconnected control head and inadequate pressure within the tank). The monitor module may include one or more user input devices (e.g., switches <NUM>, <NUM> and/or the display <NUM> being a touchscreen). These input devices are used, for example, to switch display on/off, change units (e.g., from lbs. to kg), and to activate one or more radios <NUM>, <NUM> (e.g., transmitter/receivers). The monitor module may include A/D converter <NUM> (e.g., chipset transforming analog voltage and current signals to digital signals), microcontroller <NUM> (e.g., chipset retrieving and transmitting digital signals and executing programs) and memory <NUM> (e.g., non-volatile memory for storing data and programs). Thus, analog signals transmitted via sensor connections <NUM>, <NUM>, and <NUM> are transposed into digital signals by the A/D converter and transmitted to the microcontroller for processing. The microcontroller loads, from the memory, the expected values of the sensor outputs along with the appropriate analysis program, computes response, and transmits the results to the display, indicator lights or radios. The monitor module may include battery <NUM> as internal power supply.

The microcontroller <NUM> stores in the memory <NUM> status information for the sensors attached to the associated suppression unit <NUM>, <NUM>, <NUM>, or <NUM>. Such information may include any combination of parameters such as: suppression unit identifying information (e.g., identification or serial number); the control head placement switch sensor <NUM> status (e.g., attached or disconnected); the pressure switch sensor <NUM> status (e.g., OK or low pressure); the agent temperature (e.g. from a temperature sensor (e.g., <NUM>), such as a thermistor on or in the suppressant tank); the agent level within the tank (e.g., from the liquid level sensor <NUM>); the computed agent mass (e.g., from the measured temperature and the agent level data); the monitor module battery <NUM> charge level; the monitor module connectivity status (e.g., connected to other monitor module(s), connected to hand held device <NUM> (<FIG>), connected to gateway(s) <NUM> (<FIG>) or disconnected); and the like. In the case when the particular monitor module is connected (link <NUM>-<FIG>) to a second monitor module (e.g., it receives status information transmitted by the monitor module of a neighboring suppression unit), the microcontroller also stores the status information for this second monitor module within the memory in the analogous format. For multiple monitor modules connected together, the memory of each monitor module is sufficiently large to contain status information of all the suppression tank units located within a given site or particular area thereof.

In the particular example, while the sensors <NUM>, <NUM> are connected to fire control panel <NUM> through their normally closed (NC) terminals, the normally open (NO) terminals are connected to the monitor module <NUM>. The reversed configuration is also possible with NC sensor switch terminals connected to the control panel and the NO terminals connected to the monitor module. The monitor module <NUM> offers localization of the fault condition warning at each individual unit. This offers significantly simplified system inspection for fault conditions.

In addition, the exemplary monitor module <NUM> is connected to electronic level sensor <NUM> via connection <NUM> (<FIG> and <FIG>). In this case, the sensor <NUM> supplies data indicative of the agent quantity present within the associated suppressant tank. The monitor module <NUM> display may locally display the status information for any given tank including connectivity of the control head, pressure condition within the tank, and the agent quantity. The monitor module radios may provide communication: with remote sites (e.g., offsite monitoring); with other monitor modules; and/or with a user's local hand held device <NUM> (<FIG>) such as a mobile phone, tablet, laptop, or other portable device. Exemplary short range wireless communication <NUM> and <NUM> may be Bluetooth via one of the radios (e.g., <NUM> - <FIG>). Alternative wireless communication protocols may be used if suitable, including WiFi, ZigBee, and the like). An example of a peer-to-peer network using Bluetooth protocol is a Bluetooth mesh network (Bluetooth mesh networking). This provides simultaneous communication of multiple monitor modules <NUM> among each other and with hand held device <NUM> and gateway <NUM>. The hand held device <NUM> may further communicate system status to a remote notification station <NUM> (<FIG>), such as monitoring center or fire station. Exemplary communication <NUM> is data over the wireless carrier's network and internet (e.g., over the radio <NUM>). One or more servers (not shown, e.g., cloud servers) may intervene in the communication <NUM> and may store relevant data about and from the system (e.g., and about and from other systems at other facilities). Alternative communications <NUM> may be Ethernet or WiFi (e.g., with another radio) via router/modem (e.g., cable modem) to the internet or may comprise a connection to a telephone landline. The monitor module may thus provide local or remote monitoring and diagnosis of the suppression system <NUM> without connection to or other use of the fire control panel <NUM>. Consequently, the monitor module is not subject to requirements for re-approval/re-certification typically mandated by codes and industry standards.

Communication between the monitor modules <NUM> and the hand held device may be direct for all monitor modules <NUM> or may be direct for some but indirect for others. As an example, the monitor modules <NUM> may be spread far enough apart that the hand held device can't communicate with all of them from a given location (e.g., the total span exceeds Bluetooth range). However, the gaps between monitor modules <NUM> may be small enough to allow chained communication <NUM> (e.g., with gaps less than Bluetooth range). Thus, each of the monitor modules <NUM> may be configured to share its data via chained inter-module communication <NUM> with all the other modules and store such data from all the modules. Thus, when a technician arrives, the technician's hand held device <NUM> may communicate <NUM> with just one module <NUM> to acquire data from all.

Such chained communication or other inter-module communication <NUM> has uses even where all modules <NUM> are within range of each other or the hand held device. For example, to save power, the modules <NUM> may be configured to normally be in a low power sleep mode and wake up to store and share data at specific times (e.g., daily at 12am and 12pm). The technician arriving between such times may then manually awaken one of the modules <NUM> (e.g., by pressing a button/switch) to then establish communication <NUM> between that module and the hand held device to then download to the hand held device the data from all modules <NUM> stored on the single awake module.

<FIG> show example screens on the hand held device <NUM> associated with the task of inspecting an example suppression system. In an exemplary situation, upon entering the equipment room, if not earlier, the inspecting technician signs into the suppression system monitoring application via a login screen (not shown). The app on the device <NUM> may then (or may already automatically have) establish communication <NUM> with the monitors <NUM>. Upon logging in, the exemplary app displays the different suppression systems pre-authorized to the technician together with their status information (<FIG>). The pre-authorized systems might comprise all systems serviced by the technician's company or may be the limited fraction of those assigned to the technician's service area or the yet more limited fraction represented by that day's route of the technician, among other possibilities. The app may use text, graphics, or some combination thereof to display in a user-readable format information about system status. In some exemplary embodiments, auditory alerts or visual indicators, for example, a sound or light on handheld device <NUM>, may also be used to provide an "alert". In one example of the <FIG> display screen; a checkmark within a green circle represents "system normal" status; a triangle within a yellow circle represents "system warning" status (e.g., sensor connectivity is intermittent, sensor battery is close to discharging, or the like); an exclamation mark within a red circle represents "supervisory fault" status (e.g., agent level too low, tank pressure too low, control head(s) disconnected, sensor battery discharged, lost sensor connectivity, or the like). Selecting (e.g., tapping the associated line on the display) any one of the overviewed systems results in displaying more detailed information (<FIG>) including status information of all the associated suppression tank units. Further selection of the particular tank unit results in displaying detailed status information pertaining to that tank unit (<FIG>) including sensor data, sensor connectivity, sensor battery level(s) and pinpoints specific fault(s) if present. Other system parameters may also be displayed such as specified (or expected) condition(s), tank unit specification (e.g. size, material, diameter, type of agent).

As discussed above, one characteristic of some embodiments of the monitoring module is to share a sensor or switch with the fire control panel <NUM> by using different poles or other outputs of that sensor or switch. <FIG> illustrates this schematically in the context of an exemplary control head placement switch sensor <NUM> based on that of <CIT>. The switch sensor <NUM> has a body <NUM> having a collar portion <NUM> encircling an opening <NUM> dimensioned to receive a base portion of the control head. In <CIT> the control head mounts atop a discharge valve, the collar is mounted to a top fitting of the discharge valve. Alternatively, in <FIG>, control head extends from the side of the valve <NUM> and the head placement switch sensor <NUM> may be positioned with the axis of its opening extending horizontally (transverse to the tank fitting and valve axis). A trigger <NUM> is positioned to have a pivoting range of motion about a pivot <NUM> between an extended condition and a retracted or depressed condition (extended shown). The exemplary switch sensor <NUM> is configured so that the trigger is depressed by the proper installation of the control head (e.g., by the placement of a swivel nut). The switch sensor <NUM> further comprises a switch <NUM> coupled to the trigger via a plunger <NUM>. The exemplary switch <NUM> is a stock dual output switch offering three poles: a common pole <NUM>; a normally closed (NC) pole <NUM>; and a normally open (NO) pole <NUM> connected through a wire harness <NUM>. The exemplary wire harness has six conductors with three conductors <NUM>, <NUM>, <NUM> connected to the common pole, two conductors <NUM>, <NUM> connected to the NO pole, and one conductor <NUM> connected to the NC pole. Alternatively, two conductors could be connected to the NC pole and one conductor to the NO pole. The multiple conductors facilitate universal installation of the sensors within the common circuit loop <NUM> connected to the control head monitor supervisory circuit <NUM> within the fire control panel. For example, the sensors (e.g., all the control head sensors of the particular unit) may be wired in-parallel through the common and NO poles. In that case, conductors <NUM>, <NUM> comprise the common pole connections, while the conductors <NUM>, <NUM> comprise the NO pole connections within the common circuit loop <NUM>. When any switch closes due to removal of the control head, the common circuit loop is shorted and the supervisory circuit <NUM> detects this short and communicates to the main processing unit <NUM> within the fire control panel <NUM> a supervisory fault condition. The remaining two conductors <NUM>, <NUM> within the wire harness <NUM> may be wired to the monitor module <NUM>. In this case, the monitor module is configured to detect NC condition. When the control head is removed, the conductors <NUM>, <NUM> open and the monitor module issues appropriate supervisory fault warning locally for the particular tank pair (e.g., warning light or alphanumeric indication of particular fault). In parallel, this supervisory fault status is also communicated to the hand held device and displayed in the monitoring application (<FIG>).

With only one of the normally open (NO) conductor and normally closed (NC) conductor of a given such switch coupled to the fire control panel, the other is free for use in a secondary monitoring system such as the monitor module <NUM>. Coupling of the secondary monitoring system to the otherwise unused contact does not affect code or other compliance. Thus, the addition of or subsequent modifications to the secondary monitoring system may be made without all the complications required to make modifications to the fire control panel.

<FIG> shows one alternative example of a fire suppression system <NUM> at a similar level to <FIG>. Other details may be drawn from those of the <FIG> system. The system includes communication gateway <NUM>, which is used to collect, store and transmit information from monitor modules to different receivers illustrated in <FIG>. Example receivers include hand held device <NUM> and remote monitoring station <NUM>. The information may also be stored on a cloud storage <NUM> or any other suitable local or remote data server. This data server may be used to transmit suppression system information to mobile device(s) or remote monitoring station. The communication gateway contains one or more radios <NUM>, <NUM>, <NUM> (<FIG>) to receive signals from monitor modules for example by Bluetooth protocol and to further transmit these signals to mobile phone for example by Bluetooth protocol and to cloud storage via for example Wi-Fi protocol or cellular protocol. Similarly, the communication gateway contains one or more interfaces <NUM> and <NUM> wired via Ethernet or fiber optic cables to remote monitoring or cloud storage. The different radios may be enabled on and off by one or more switches <NUM>, <NUM>, <NUM> (e.g., DIP switches under a locked cover). The communication gateway also contains microprocessor <NUM> to control operation of the radios and interfaces, to store suppression system status in memory <NUM>, and drive internal display <NUM>. The communication gateway is preferentially externally powered (e.g., connected to AC power), but may also contain internal battery <NUM> connected to the power circuit <NUM> (e.g., having transistor or relay switches to switch between external power and battery) to allow operation during power interruption.

<FIG> shows exemplary suppression system information displayed by the communication gateway through its build-in display. Also shown is the status of different radios and interfaces; as above, this information may be displayed through auditory or visual signs, textually, graphically, or in a combinations of these.

<FIG> and <FIG> show screenshots of a user interface displayed on a computer screen or a web application (e.g., at the remote monitoring location <NUM>). The suppression system information is displayed in a manner analogous to that shown with the mobile application in <FIG>. Specifically, <FIG> overviews the different suppression systems accessible to the technician together with their status information. For example, a checkmark within a green circle represents "system normal" status, while an exclamation mark within a red circle represents "supervisory fault" status (e.g., agent level too low, tank pressure too low, control head(s) disconnected, sensor battery discharged, and/or sensor connectivity loss). Selecting any one of the overviewed systems results in displaying more detailed information (<FIG>) including status information of all the associated suppression tank units. Further selection of the particular tank unit results in displaying detailed status information pertaining to that tank unit including sensor data, sensor connectivity, and sensor battery level(s) and pinpoints specific fault(s) if present.

As a further variation in cases with liquid suppressant, further aspects of suppressant condition may be monitored. For example, in <FIG>, cylinder <NUM> may contain a liquid suppressant such as water. When activated for discharge, cylinder <NUM> containing the driver gas would drive water instead of clean agent through the system, and the twin-fluid mixture atomizes to form a water mist that is injected at the nozzles <NUM>. In this case, the water quality in cylinder <NUM> may be monitored for pre-cursors to corrosion with sensors (e.g., water conductivity through capacitance, water turbidity via an LED/photodiode system) that may be integrated with the liquid level sensor <NUM>. <FIG> show a capacitance sensor <NUM> (e.g., a capacitor where the liquid in the tank is between the two poles (shown as rods, although plates or other configurations are possible)) at the lower end of a tube of the liquid level sensor. The exemplary liquid level sensor has a magnetic switch array in the tube interfacing with a magnetic float (see <CIT> "Magnetic Trap Suppression Tank Level Sensor" and <CIT>). The exemplary sensor leads pass through the tube. For an aqueous liquid, the module <NUM> may be pre-programmed with limit parameters on capacitance for particular agent blends. The particular blend may be selected in the factory or system installation. The module may periodically compare measured capacitance to the limit parameters to assess quality and determine a fault condition if out of limit. The module may communicate the fault condition as discussed for other faults and parameters and sensors herein.

Water flow rates may be monitored during the discharge via a mass flow meter <NUM> (<FIG>) (e.g., a paddle wheel, turbine meter) that may be connected in the discharge port of the valve. Gas leakage from cylinder <NUM> may be monitored for acoustics with a microphone <NUM> (e.g., embedded in monitor module <NUM> of <FIG>). The signals from these sensors would be incorporated into the monitor module <NUM> as shown in <FIG>. The module <NUM> may be pre-programmed with target flow parameters. These parameters may be determined as desired parameters when the system is tailored for a particular site and then verified by on-site testing. The test parameters may then be programmed into the module for in-use comparison. During a discharge, the module <NUM> compares the measured flow rate to the stored target. The module may store and communicate a fault the actual flow rates fall outside some predetermined range around the nominal target.

The liquid quality sensor and mass flow rate information are sent as inputs <NUM>, <NUM> alongside <NUM>, <NUM>, <NUM>.

Claim 1:
A fire suppression system comprising:
a tank unit (<NUM>, <NUM>, <NUM>, <NUM>) comprising:
a tank body having a first port and an interior for storing at least one of fire suppressant and driver gas;
a discharge assembly mounted to the first port and comprising:
a discharge valve (<NUM>, <NUM>); and
a first monitoring switch or sensor (<NUM>, <NUM>); and
a first monitoring system (<NUM>);
wherein the first monitoring switch or sensor (<NUM>, <NUM>) has a normally closed output (<NUM>) and a normally open output (<NUM>), with the first monitoring system (<NUM>) being coupled to one of the normally closed output and the normally open output,
and in that the system further comprises:
a second monitoring system (<NUM>) coupled to the other of the normally closed output and the normally open output.