SOLENOID MONITORING SYSTEM

Abstract

Systems and methods for a solenoid monitoring detection system that can detect the presence or absence of a solenoid plunger within a solenoid coil. These systems can be used to verify the correct reassembly of a solenoid valve after it has been disassembled for testing.

Description

SOLENOID MONITORING SYSTEM Technical field of the invention This description relates to the field of evaluation systems for electric solenoids, particularly systems for determining whether an electric solenoid valve has been reassembled after testing. Background of the invention To fight fires in modern buildings, firefighters use a wide variety of tools, but they also rely on the building's existing systems. Modern buildings almost universally include fire suppression systems to control or extinguish fires. The extinguishing agent can be a gas or a liquid. Fire suppression systems generally follow a fairly standardized principle. The fire extinguishing agent is held in a series of pipes or tanks, usually pressurized, that are distributed throughout the building. In a wet pipe system, water is stored inside the pipes, while in a dry pipe system, water is stored outside the building and the pipes contain air, nitrogen, or another pressurized gas.In a gas fire suppression system, the extinguishing agent is contained in pressurized tanks or vessels within the facility. These pipes contain several sprinklers or nozzles that, when activated, spray the extinguishing agent onto a predetermined area. In a typical fire sprinkler system, when a fire is detected, the sprinklers in the pipe network are activated by heat and spray the extinguishing agent. This activation is usually carried out by a heat-sensitive element, an integral part of the sprinkler that is triggered by the heat of the fire. Generally, each sprinkler has its own heat-sensitive element and is activated independently of all other sprinklers. When a sprinkler is activated, the extinguishing agent contained in the pipes or tank is dispensed by the sprinkler to a predetermined location. This action dispenses the extinguishing agent onto the fire and serves to control or extinguish it. These systems can be initiated by the activation of smoke, flame, or heat detectors in the protected area. Originally, sprinklers included a breakable element that would shatter when exposed to sufficient heat.The rupture of this component created a pressure outlet at the sprinkler head, which was activated by the effective opening of the sprinkler head. This directed pressurized water from the pipes toward the open sprinkler. In dry pipe and pre-action sprinkler systems, the pipes are not filled with water, but with pressurized gas. The gas pressure in the sprinkler system typically holds a flap valve in the dry pipe closed, which in turn holds water, which may be from a pressurized municipal system or some type of pressurized tank. When a sprinkler head is activated, the gas initially escapes from the head in the same way as water in the system described above. This causes the gas pressure to drop in the dry pipe system. Once the pressure falls below a certain threshold, the flap valve opens, and pressurized water enters the pipe. The water flows into the sprinkler head and continues to expel the gas and replace it with water until the water itself reaches the sprinkler head and begins to spray onto the fire. μλ / t / zuzz / u í yyou Because sprinkler systems deliver water to the area of ​​the open sprinkler head, it is clear that a false alarm can have damaging consequences. If the sprinkler head opens improperly (for example, because the heat-sensitive element breaks due to an impact rather than heat), the system will supply and spray water from that head. Furthermore, it will continue to do so until the water supply is shut off. Therefore, the sprayed water can cause considerable property damage even if there is no fire near the sprinkler head. To address this problem, pre-action fire sprinkler systems were developed. These utilize the basic concept of a dry pipe system, where water is not typically contained within the pipes, but the pipes are also not usually maintained at considerable pressure. Therefore, opening a sprinkler head is often insufficient to release water. Instead, water is kept out of the sprinkler pipes by an electrically operated valve commonly known as a deluge valve. The deluge valve's operation is controlled by independent flame, heat, or smoke detectors that are not dependent on the sprinkler heads. In a pre-action fire sprinkler system, two distinct events must occur to initiate sprinkler discharge. First, the detection system must identify a potential fire (for example, by smoke detection) and then open the deluge valve to allow water to flow into the sprinkler pipes. At this stage, the system essentially becomes a wet-pipe sprinkler system. Once an individual sprinkler head is released after this time, water can flow from the system, through the open head, and onto the fire. As is evident, the two stages can occur in opposite order and very close to, if not simultaneously with, each other. The key, however, is that both events must occur for the sprinkler to activate and discharge water, which can dramatically reduce the damage from a false alarm situation. To provide control over fire sprinkler systems, there is usually some type of control panel that serves as a central station for the operation of the various components. In pre-action systems, deluge valve control may be included as part of the main control system, or it may be controlled by a separate release panel. The latter arrangement is usually preferred because it allows the two systems to be controlled independently. While it is generally permitted to install both controls on a single panel, it should be obvious that a single false alarm on that panel could result in the sprinklers being activated. However, if two separate panels are present, each can act as a control for the other. The deluge valve is typically a solenoid valve, and the solenoid is activated by the release panel to release extinguishing agents to the sprinkler heads and nozzles if a potential fire is detected. This arrangement is especially common in pre-action (dry pipe) systems. In these systems, when the fire or sprinkler release panel detects a fire via heat, smoke, or other detectors, the panel typically activates the solenoid to flood the sprinkler piping system with extinguishing agent, preparing it to extinguish the fire. Extinguishing agent systems or other systems may also use similar solenoids to maintain the extinguishing agent contained in the pressurized tank or at other points in the extinguishing system. While solenoid valves can be very useful and safe as deluge valves, they also present a significant risk. Specifically, a solenoid valve must be properly mounted and electrically operational to open. Because a solenoid valve relies on an electromagnetic force to move the solenoid plunger and open the valve, any problem with the electromagnetic coil or associated electronics will prevent the valve from opening. Similarly, if the plunger is not positioned within the coil, even effective coil actuation will not open the valve. Since the system relies heavily on the operation of the deluge valve, it is necessary to test the release panel systems regularly. This includes verifying that the solenoid coil will correctly generate an electromagnetic field to activate the plunger. However, because the plunger holds back water to prevent it from entering the sprinkler system's piping, it is clearly undesirable to actually activate the plunger during a test. Instead, traditional testing methods involve removing the plunger from the coil and activating the coil while the components are separated. This allows for verification of the coil's proper activation without actually opening the deluge valve.However, since this test involves disassembling the solenoid valve, there is concern that the valve may be incorrectly reassembled after the test, which could result in a dangerous situation where the valve cannot be opened using the release panel. ma / t / zuzz / u í aaou SUMMARY OF THE INVENTION The following is a summary of the invention to provide a basic understanding of some aspects of it. This summary is not intended to identify key or critical elements of the invention or to delimit its scope. The sole purpose of this section is to present some concepts of the invention in a simplified manner as a prelude to the more detailed description presented later. Due to these and other technical problems, this paper describes, among other things, a solenoid monitoring system that can detect the presence or absence of a solenoid plunger within a solenoid coil. Such systems can be used to verify the correct reassembly of a solenoid valve after it has been disassembled for testing. This document describes, among other things, a system for detecting the presence of a solenoid plunger within a solenoid coil, wherein the system comprises: a solenoid coil assembly comprising a solenoid winding within an electrically conductive coil housing; a power supply electrically connected to the electrically conductive coil housing; and a solenoid plunger assembly comprising a solenoid plunger within an electrically conductive plunger housing; wherein, when the solenoid plunger assembly is correctly positioned within the solenoid coil assembly, the electrically conductive coil housing is in electrical communication with the electrically conductive plunger housing. In one embodiment, the system further comprises a microcontroller for detecting the flow of current from the power supply, through the coil box, and into the solenoid box. In one embodiment, the system further comprises an insulating cover arranged between the solenoid winding and the electrically conductive coil housing. In one embodiment, the system further comprises an overmold surrounding the electrically conductive coil box. In one embodiment of the system, the coil box comprises metal. In one embodiment of the system, the solenoid housing comprises metal. In one embodiment of the system, the solenoid plunger assembly further includes a valve that is opened by the movement of the solenoid plunger. In one embodiment of the system, the valve is a deluge valve in a fire sprinkler system. Also described herein, in one embodiment, is a system for detecting the presence of a solenoid plunger within a solenoid coil, wherein the system comprises: a solenoid coil assembly comprising a solenoid winding; a solenoid plunger assembly comprising a solenoid plunger; an electrical circuit connected to the solenoid winding, wherein the circuit comprises: an isolated power supply; a Colpitts oscillator; a low-pass filter, which rectifies and attenuates the output of the oscillator; a non-inverting amplifier, which amplifies the output of the low-pass filter; a comparator for comparing the output of the amplifier with a set voltage; and a monostable multivibrator acting on the output of the comparator to drive a FET optocoupler. In one embodiment of the system, the low-pass filter, the non-inverting amplifier, and the comparator are all part of a microcontroller. In one embodiment of the system, the ma / t / zuzz / u í aaou microcontroller supplies two different types of signals to the solenoid winding. In one embodiment of the system, the microcontroller detects the waveforms resulting from both signals. In one embodiment of the system, the first of the signals is used to detect the inductance of the solenoid winding. In one embodiment of the system, the first of the signals is a single, positive pulse of fixed voltage and fixed time. In one embodiment of the system, the second of the signals is used to detect the capacitance of the solenoid winding. In one embodiment of the system, the second of the signals includes packets of encoded and / or modulated signals. Furthermore, a method for detecting the reassembly of a deluge valve in a fire sprinkler system is described herein in one embodiment, wherein the method comprises: providing a deluge valve that includes a solenoid formed by a solenoid plunger removable from the interior of a solenoid coil; connecting a circuit to the solenoid coil; measuring from the circuit at least one of the inductances or capacitances of the solenoid coil; and determining from the measurement whether the solenoid plunger is inside the solenoid coil. BRIEF DESCRIPTION OF THE DRAWINGS μλ / t / zuzz / u í aaou Figures 1A, 1B, and 1C depict a solenoid valve that can be used in a sprinkler system. Figure 1A shows a perspective view of the fire solenoid valve. Figure 1B shows a side view, and Figure 1C shows an exploded view. Figure 2 provides a block diagram of a first embodiment of a solenoid monitoring system. Figure 3 provides a circuit diagram of a second embodiment of a solenoid monitoring system. Figure 4 provides a circuit diagram of a third embodiment of a solenoid monitoring system. Figure 5 provides a drawing of a cut through the solenoid housing. ma / t / zuzz / u í aaou DETAILED DESCRIPTION OF THE INVENTION Solenoid valves (100), such as those used in fire sprinkler systems, typically come in three main parts, as shown in Figures 1A, 1B, and 1C, as well as Figure 5. As shown in these figures, there is usually a solenoid coil component (101) surrounding a solenoid plunger component (103). The solenoid plunger component (103) includes the movable solenoid plunger, which is connected to the physical valve (107) to control flow through a coupled pipe. The solenoid plunger component (103) and the solenoid coil component (101) are usually joined by a single nut (105) located at the end of the solenoid plunger component (103). As can be seen more clearly in Figure 5, the solenoid coil component (101) follows a fairly typical construction. Specifically, the solenoid coil component (101) comprises a coil winding (511) which, when energized, acts as the electromagnet to produce a magnetic field within the vacuum (521). The coil winding (511) is contained within a sheath (513) formed by an electrical insulator to provide structure to the coil winding (511) as well as electrical insulation for the coil winding (511). In Figure 5, the insulating sheath (513) comprises a molded plastic and, specifically, an epoxy filling that encloses the coil winding (511). The coil winding (511) is placed around and separated from the vacuum (521) in which the solenoid plunger shaft (503) is placed (103) through the insulating cover (513). The insulating cover (513) is typically enclosed within a coil case (501). The case (501) is typically made of metal to provide strength to the solenoid coil (101), but also to act as a magnetic focuser for the resulting magnetic field produced by the coil winding (511). As can be seen in Figure 5, the vacuum (521) usually passes through the cover (513) and the case (501). However, the cover (513) is not typically located between the case (501) and the vacuum (521), where the vacuum (521) passes through the case (501) at points (531) and (533). This creates two metal rings, one at each of points (531) and (533), on the wall of the vacuum (521). There is also an opening at the end (535) to allow the placement of the nut (105) to hold the components together. The housing (501) is normally surrounded by an overmold (515) that serves to enclose the housing (501). The overmold (515) is also typically electrically insulated, and the representation in Figure 5 comprises a plastic structure and specifically a polycarbonate overmold (515). The overmold (515) can be used to improve the appearance of the device and to protect the housing (501), but it also serves to electrically insulate the coil housing (501) from any nearby object. The solenoid plunger component (103) typically includes two functional elements, although they are usually integrally formed. There is a shaft (503) and a valve housing (613). The shaft (503) includes the physical solenoid plunger, which moves within the shaft (503) to actuate the valve (107), which is physically internal to the valve housing (613). The valve housing (613) is typically in the form of a metal box, as is the shaft (503). However, the shaft (503) and the valve housing (613) can be, and usually are, made of different metals. The shaft (503) is metal so that it can conduct the electromagnetic fields induced by the coil winding (511) to open and close the solenoid plunger. Thus, when the solenoid coil (101) is placed on the shaft (503) of the solenoid plunger (103), the shaft (503) extends into, and generally through, the vacuum (521).In this position, the shaft (503) usually makes contact with at least part of the housing (501) at point (531) and / or point (533), or is very close to them. In particular, the shaft (503) will tend to be electrically connected to the housing (501) at point (531) and / or point (533). In the typical operation described above, electrical power for the solenoid's operation is supplied via the wires (517) through the conduit (519) to the coil winding (511), and the housing (501) is not electrified. However, it is not uncommon for wiring to be connected to the housing (501), which can act as a ground for the coil winding (511) signals. To test the solenoid valve, it is common industry practice to remove the solenoid coil component (101) from the solenoid plunger component (103) (or vice versa). Specifically, the person testing the solenoid (100) will disassemble the parts as shown in Figure 1C to prevent the deluge or pre-action valve in the fire suppression system from triggering or releasing the agent from the pressurized container into the piping while testing components designed to operate the system. By removing the plunger (103), the coil winding (511) can be safely energized as part of the test to ensure that the coil winding (511) and associated electronic components are functional.However, since the plunger component (103) is separate, the lack of electrification in the plunger component (103) prevents the plunger from moving and, therefore, the valve (107) from closing. Once the solenoid coil component (101) and the solenoid plunger component (103) are separated, the coil winding (511) can be energized without triggering the system and opening the valve (107). To verify that the coil winding (511) is properly energized, a metal screwdriver or other metal object is typically inserted into or around the solenoid coil (101). This allows a technician to verify that the coil winding (511) has developed a magnetic field. Once the operation of the solenoid coil (101) is verified, the solenoid coil (101) must be reinstalled in the solenoid plunger (103), and the nut (105) must be replaced so that the device is assembled in the configuration shown in Figure 1B. The problem is that there is nothing on the release panel (300) to detect whether the solenoid coil (101) has been reinstalled correctly after the test is completed. If the solenoid valve (100) remains disassembled as shown in Figure 1C, the valve (100) will continue to be detected as normal on the fire and sprinkler release panels because the coil component (101) remains electrically connected. However, if the solenoid valve (100) is not assembled, activating the coil winding (511) will not move the solenoid plunger (103) and the valve (107) will not open when the coil (511) is energized.This will prevent the fire suppression system from operating without manual intervention. Furthermore, in some situations, the metal test object (e.g., a screwdriver) used to test the coil's electrification (511) may remain in the coil component (101), which can cause further problems. To detect whether the coil component (101) and the plunger component (103) have been assembled or remain unassembled, several embodiments of systems for detecting the correct assembly of the solenoid valve (100) are provided herein. A first embodiment of such a system (200) is shown in Figure 2 and comprises an electrical circuit that uses inductance to determine whether the shaft (503) is present in the vacuum (521). In the embodiment of Figure 2, the circuit comprises an oscillator (201), a low-pass filter amplifier (203), a delay (205), a comparator (207), a monostable multivibrator (One Shot) (209), a FET optocoupler (211), and an isolated power supply (213), along with other associated electronic components, as shown.With the exception of the oscillator (201) and the FET optocoupler (211), in an alternative embodiment of a similar system (200), the rest of the circuit in Figure 2 can be replaced by a microcontroller. The connections to the system (200) in Figure 2 involve connections for positive (+) and negative (-) power supply (301), two connections for the release panel output and return (303), and two connections for the solenoid coil (101) and end-of-line diode assembly (307). While shown on the outside of a fire sprinkler release panel (300) in Figure 2, in an alternative embodiment, the circuit can be integrated into the fire sprinkler release panel (300) and / or another control panel in the fire suppression system. The system in Figure 2 generally operates as follows. The oscillator (201) is preferably of the type known to those of intermediate skill as a Colpitts oscillator. The output frequency of the oscillator (201) changes proportionally as the inductance of the solenoid coil (101) changes. The output of the oscillator (201) is fed to a low-pass filter (215) that rectifies and attenuates the signal to a DC voltage level that varies with the frequency. The signal is then fed to a non-inverting amplifier (203). The output of the amplifier (203) goes to a delay (205) and then to a comparator (207) where it is compared to a tunable voltage set between the voltage measured when the solenoid coil component (101) is disconnected from the solenoid plunger component (103) and when they are connected.The comparator output (207) changes state from rail to rail, differentiating when the solenoid plunger component (103) and the solenoid coil component (101) are assembled or disassembled. The comparator output (207) feeds a monostable multivibrator (209), commonly known to mid-level tradespeople as a one-shot circuit (209). This circuit provides a high output when its input is high and a variable duty cycle output when its input is low. The variable duty cycle output consists of a low signal for a period of time (e.g., 10 ms) and then a high signal for a second, shorter period of time (e.g., 500 ps). At the end of this second period, the signal returns to a low state, and so on. The one-shot output (209) activates the optically isolated FET optocoupler (211). When the FET (211) is off, the release panel (300) will indicate a problem condition (since this indicates that the solenoid coil component (101) and the solenoid plunger component (103) are not connected).Alternatively, when the coil component (101) and plunger component (103) are connected, the FET (211) will be turned on and the release panel (300) will indicate the standard operating state. Government agencies generally already require the release panel (300) to electronically monitor all valves controlling the water supply to automatic sprinkler systems, so the above new functionality is not beyond its capabilities. Therefore, since release panels (300) are generally already capable of monitoring openings, short circuits, and wiring polarity, the above modifications are easily made to allow the panel (300) to monitor that the solenoid coil (101) is connected to the solenoid plunger (103). When FET (211) is off, the oscillator's (201) output signal is effectively turned off, causing the input signal to One Shot (209) to remain low. While in this state, One Shot (209) provides an output signal that periodically rises to turn on FET (211) so that the oscillator (201) can start and essentially retest that the solenoid coil (101) is still installed on the solenoid plunger (103). If not, FET (211) turns off, and the process repeats. If the solenoid coil (101) is installed on the solenoid plunger (103), then the output of One Shot (209) rises and turns on FET (211), thus clearing the panel trouble condition. The system wiring (200) and associated solenoid valve (100) may also include standard wiring monitoring systems, as understood by people of the mid-level trade, to monitor the system for grounding, openings, and short circuits. Figure 3 provides another embodiment of a solenoid monitoring system (400). In this embodiment, a microcontroller (401) is provided to replace much of the inductance sensing circuitry as contemplated in the alternative embodiment of Figure 2. The microcontroller also enables additional sensing as described below. As in system (200), system (400) is designed to determine whether the solenoid plunger (103) is inside or outside the solenoid coil (101). In Figure 3, however, system (400) uses both inductance and capacitance calculations to further assist in solenoid sensing. In operation, the system circuit (400) will be powered by the isolated power supply (213) in the same way as in system (200). The microcontroller (401) will apply two different stimulus signal forms (421) and (423) to the solenoid coil (101), through the field-effect transistor (FET) (411). The microcontroller (401) then detects the resulting waveforms (431) and (433) of both stimulus signals (421) and (423) that have interacted with the solenoid components. The first stimulus signal (421) is also used to detect the inductance of the coils, as in the operation of the embodiment shown in Figure 2. However, the mechanism for detecting the inductance is different. The stimulus signal (421) for this detection takes the form of a single, fixed-time, fixed-voltage, positive pulse. This signal will travel to the solenoid coil (101) as shown. This signal (421) will generate a ramp voltage across the resistor of MA / t / ZUZZ / U í υυου current detection R1 (441) that produces the signal (431). Due to the fixed pulse width of the signal (421), the peak of the ramp of the signal (431) will be proportional to the inductance of the solenoid coil (101). The microcontroller (401) will detect the peak of signal (431) and determine the state of the solenoid plunger (103) relative to the solenoid coil (101). A peak in signal (431) that is too high indicates that the solenoid plunger (103) is separated from the solenoid coil (101) and should be returned. However, it should be recognized that if a metallic object (e.g., a screwdriver) other than the solenoid plunger (103) is placed on the solenoid coil (101), this could cause the peak of signal (421) to be insufficient to trigger a missing coil indication on its own. This is where the second stimulus signal (423) comes in. The second stimulus signal (423) is used to detect the parasitic solenoid coil capacitance (101). In the embodiment shown, the second stimulus signal (433) takes the form of encoded and / or modulated signal packets applied as shown. The baud rate is high enough to penetrate the parasitic capacitance of a mounted coil and be detected by a HiZ input (401) on the microcontroller. When the solenoid coil capacitance (101) is sufficiently large, the received signal (433) will be distinct, and the microcontroller will be able to resolve its encoded data. This indicates that the solenoid plunger (103) is in place. When the solenoid coil capacitance (101) decreases significantly, the received signal (433) will be compromised, and its data will be unrecoverable or corrupted, indicating that the solenoid plunger (103) has been withdrawn.Therefore, when the microcontroller (401) can receive and decode the same data that it transmitted (e.g., the signal (423) and the. MA / t / ZUZZ / U í υυου signal (433) include the same data), concludes that the solenoid plunger (103) is in place. This methodology can distinguish between the data signal and the random noise signal and, in general, can also detect if an object other than the solenoid plunger (103) is placed in the coil. When both stimulus signals (421) and (423) continue to produce qualifying responses (431) and (433), the microcontroller (401) will continuously provide a repetitive pulse-type signal to the relay monitoring circuit (451). The relay monitoring circuit (451), in turn, will keep the monitoring relay (453) energized, indicating that the solenoid plunger (103) is in place on the solenoid coil (101) and that normal, desired operation is taking place. Any de-energization of relay (453) will signal a monitoring condition to the control panel (300), which may trigger an alarm condition or provide an indication of concern. Figure 4 provides yet another embodiment of a solenoid monitoring system (500). As in embodiment (400) of Figure 3, a microcontroller (401) is provided to replace much of the circuitry as contemplated in the alternative of Figure 2. The microcontroller (401) also enables additional detection as described below. As in systems (200) and (400), system (500) is designed to determine whether the shaft (503) is in or out of the vacuum (521). In Figure 4, however, the system uses the material characteristics of the solenoid coil component (101) and the solenoid plunger component (103) to detect the continuity of an electrical circuit formed when the solenoid coil component (101) and the solenoid plunger component (103) are together. As discussed previously, the housing (501) is normally in electrical communication with the shaft (503) only when the shaft (503) is in a vacuum (521). Specifically, when correctly positioned, the shaft (503) will generally contact at least a portion of the housing (501) at point (531) and / or point (533), or be very close to them to allow electrical communication between the metal components. This is typically to provide a common ground. In particular, the shaft (503) will tend to be in electrical connection with the housing (501) at point (531) and / or point (533). This electrical connection allows the system (500) to detect that the solenoid plunger (103) and solenoid coil (101) have reconnected, as shown in Figure IB. Figure 4 shows one embodiment of the system (500) for performing such detection. In Figure 4, the microcontroller (401) has an electrical connection (601) to the box (501). This electrical connection can be direct or via another component of the solenoid coil (101) that is in electrical communication with the box (501). In one embodiment, the connection is actually through the existing ground wire connected to the box (501). Alternatively, a bracket can be added to connect the conduit (519), which is often formed into screw threads for connection to other sprinkler system components and is typically in electrical communication with the box (501), possibly by being formed together.While the above methods work well for upgrading existing solenoid valves (100), it is also possible to purposely build electrical connections into the coil component (101) in order to provide signals to the box (501). The electrical connection (601) is attached to a power supply (603). The power supply (603) will normally be a small DC power supply (e.g., less than 10 volts) and in the represented embodiment comprises a 5-volt DC source. However, alternative power sources may be used in alternative embodiments, including converting the power supplied for the operation of the solenoid valve (100) for this purpose. The power supply (603) is typically not designed to provide direct power, but simply to act as a voltage and / or current source that can be sensed by the microcontroller (401). As such, it will be electrically isolated from the power supply that will power the coil winding (511). The microcontroller (401) also has an electrical connection (605) to the solenoid plunger component (103). In the embodiment shown, the connection is to the valve housing (613) of the solenoid plunger component (103); however, it can be to any part of the solenoid plunger component (103) that is in electrical communication with the metal shaft (503) or that would otherwise be in electrical communication with the housing (501) when the solenoid plunger component (103) is correctly positioned with the solenoid coil component (101) as shown in Figure IB. That is, when the shaft (503) is in the vacuum (521), the electrical connection between the shaft (503) and points (531) and / or (533) serves to complete the electrical connection of (601) and (605). When the shaft (503) is not in the vacuum (521), this connection is broken.In yet another alternative embodiment, the connection (605) can be made with the nut (105) instead of with a component of the solenoid plunger (103), but this is generally not preferred as it can make the nut (105) difficult to machine, although it would provide a suitable electrical connection. Furthermore, when retrofitting an existing solenoid valve (100), the electrical connection (605) can be made through a bracket attached to the valve housing (613) since the valve housing (613) generally lacks an insulating overmolding. As can be seen in Figure 4, the power source (603) is typically always energized (for example, by being a chemical battery). Thus, when the solenoid plunger (103) is in position over the solenoid coil (101) as in Figure 1B, the electrical path (601) to (605) is complete, and the microcontroller (401) will detect the voltage produced by the power source (603) at connection (605). When the solenoid coil (101) and the solenoid plunger (103) are separated as in Figure 1C, the electrical connection is broken, and the microcontroller (401) will not detect the voltage, indicating that the assembly is still disassembled. It should be evident that the presence of an alternative conductor (e.g., a screwdriver) placed in the vacuum (521) can energize the coil winding (511), but will not complete the electrical path between (601) and (605) because the connection (605) of the plunger component (103) is missing. Therefore, the system (500) will be able to detect whether the specific solenoid coil component (101) and the solenoid plunger component (103) are mounted or dismounted, even if there is an alternative conductor in the vacuum (521). In an alternative embodiment to further ensure the connection, the microcontroller (401) can provide that the signal from the power supply (603) includes some form of encoding. Therefore, when the signal is received back at the microcontroller (401) from the connection (605), the microcontroller (401) would also have to detect the encoding to confirm the connection. In a further embodiment, the specific resistance or other electrical characteristic of the plunger component (103) could be known, and the microcontroller (401) could use that known value to verify that the signal from the connection (605) is the expected one. Although the invention has been disclosed along with a disclosure of certain embodiments, including those currently believed to be useful embodiments, the detailed description is intended to be illustrative and should not be construed as limiting the scope of this description. As a person of average skill will understand, the present invention encompasses embodiments other than those described in detail herein. Modifications and variations of the described embodiments may be made without departing from the spirit and scope of the invention. Furthermore, it shall be understood that any of the ranges, values, properties, or characteristics provided for any individual component of this disclosure may be used interchangeably with any range, value, property, or characteristic provided for any of the other components of the disclosure, where compatible, to form an embodiment having defined values ​​for each of the components, as set forth herein. In addition, the ranges provided for a genus or category may also apply to species within the genus or members of the category unless otherwise stated. A person of average skill would understand that the qualifier "generally" and other similar qualifiers used in this case are intended to accommodate recognizable attempts to fit a device to the qualified term, which, however, may not be entirely successful. This is because terms like "spherical" are purely geometric constructs, and no component or relationship in the real world is truly spherical in the geometric sense. Variations in geometric and mathematical descriptions are unavoidable due, among other things, to manufacturing tolerances that result in variations in shape, defects and imperfections, non-uniform thermal expansion, and natural wear. Furthermore, there exists for every object a level of magnification at which geometric and mathematical descriptors fall short due to the nature of the material.A person of average skill would therefore understand the term generally and the relationships contemplated herein independently of the inclusion of such qualifiers to include a range of variations of the literal geometric meaning of the term in view of these and other considerations.

Claims

1. A system for detecting the presence of a solenoid plunger within a solenoid coil, the system characterized in that it comprises: a solenoid coil assembly comprising a solenoid winding within an electrically conductive coil housing; a power supply electrically connected to the electrically conductive coil housing; and a solenoid plunger assembly comprising a solenoid plunger within an electrically conductive plunger housing; wherein, when the solenoid plunger assembly is properly placed within the solenoid coil assembly, the electrically conductive coil housing is in electrical communication with the electrically conductive plunger housing.

2. The system according to claim 1, characterized in that it further comprises a microcontroller for detecting the flow of current from the power source, through the coil box and into the solenoid box.

3. The system according to claim 1, characterized in that it further comprises an insulating cover arranged between the solenoid winding and the electrically conductive coil housing.

4. The system according to claim 1, characterized in that it further comprises an overmold surrounding the electrically conductive coil box.

5. The system according to claim 1, characterized in that the coil box comprises metal.

6. The system according to claim 1, characterized in that the solenoid housing comprises metal.

7. The system according to claim 1, characterized in that the solenoid plunger assembly further includes a valve that is opened by the movement of the solenoid plunger.

8. The system according to claim 7, characterized in that the valve is a deluge valve in a fire sprinkler system.

9. A system for detecting the presence of a solenoid plunger within a solenoid coil, the system being characterized in that it comprises: a solenoid coil assembly comprising a solenoid winding; a solenoid plunger assembly comprising a solenoid plunger; an electrical circuit connected to said solenoid winding, wherein the circuit comprises: an isolated power supply; a Colpitts oscillator; a low-pass filter, which rectifies and attenuates the output of the oscillator; a non-inverting amplifier, which amplifies the output of the low-pass filter; a comparator for comparing the output of the amplifier with a set voltage; and a monostable multivibrator acting on the output of the comparator to drive a FET optocoupler.

10. The system according to claim 9, characterized in that the low-pass filter, the non-inverting amplifier and the comparator are part of a microcontroller.

11. The system according to claim 10, characterized in that the microcontroller supplies two different types of signals to the solenoid winding.

12. The system according to claim 11, characterized in that the microcontroller detects the waveforms resulting from both signals.

13. The system according to claim 12, characterized in that a first of said signals is used to detect the inductance of the solenoid winding.

14. The system according to claim 13, characterized in that the first of the signals is a single pulse of fixed time, fixed voltage and positive.

15. The system according to claim 14, characterized in that a second of the signals is used to detect the capacitance of the solenoid winding.

16. The system according to claim 15, characterized in that the second of the signals includes packets of encoded and / or modulated signals.

17. A method for detecting the reassembly of a deluge valve in a fire sprinkler system, the method being characterized in that it comprises: providing a deluge valve including a solenoid formed by a solenoid plunger removable from within a solenoid coil; connecting a circuit to the solenoid coil; measuring from the circuit at least one of the inductance or capacitance of the solenoid coil; and determining from the measurement whether the solenoid plunger is within the solenoid coil.

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