Solid state water level switch

Abstract

Solid state water level sensors and related pump switches based on differential pressure analysis are disclosed. Various pump control systems, such as sump pump controls for basement waterproofing, which include solid state water level detection technology are also disclosed.

Description

[0001] Docket No. D2013-7005WO SOLID STATE WATER LEVEL SWITCH FIELD OF THE TECHNOLOGY At least some aspects relate generally to sensors for measuring water level and, more particularly, to solid state water level sensors which may find utility in pump switches for basement waterproofing systems and other applications. BACKGROUND Water sensors can be used to detect the presence of water in locations where water should not be present and may be integral to various pump switches and systems for controlling water, such as in basement waterproofing systems. SUMMARY In accordance with one or more aspects, a solid state water level sensor is disclosed. The sensor may comprise a differential pressure sensor, a column configured to sit in a reservoir intended to collect undesired water, a first tube having a first end and a second end, the first end connected to the differential pressure sensor and the second end in fluid communication with a source of ambient air, and a second tube having a first end and a second end, wherein the first end is connected to the differential pressure sensor and the second end is in fluid communication with an isolated headspace above any water level present in the column. In some aspects, the differential pressure sensor has a sensitivity down to at least as low as about 1psi. The sensor may further comprise a backup conductivity sensor. In accordance with one or more aspects, a solid state water level switch comprising a solid state water level sensor as described herein is disclosed. In some aspects, the switch may further comprise a processor in communication with the differential pressure sensor, wherein the sensor is configured to communicate differential pressure data to the processor and the processor is configured to correlate the differential pressure data to a reservoir water level. In some aspects, the processor is a controller configured to actuate a pump in response to the reservoir water level exceeding a threshold level. The switch may be a TRIAC switch. Docket No. D2013-7005WO In accordance with one or more aspects, a water level control system is disclosed. The control system may comprise a switch as described herein and a pump in communication with the switch. In some aspects, the pump may be a basement sump pump for basement waterproofing. In other aspects, the pump may be a marine bilge pump. In at least some aspects, the pump may be associated with sewage control or radon control. In accordance with one or more aspects, a method of detecting a water level in a reservoir is disclosed. The method may involve steps of detecting an ambient pressure level in an environment, detecting a pressure level in an isolated headspace above any undesired water present in the reservoir, performing differential pressure analysis between the ambient pressure level and the isolated headspace pressure level, and correlating the differential pressure analysis to a water level in the reservoir. In some aspects, the reservoir may pertain to a basement sump. In other aspects, the reservoir may pertain to a marine bilge. In some aspects, the method may further comprise supplementing detection by monitoring a conductivity level in the reservoir. In accordance with one or more aspects, a method of controlling a water level in a reservoir is disclosed. The method may comprise steps of detecting a water level in the reservoir as described herein and actuating a pump in response to the detected water level. In some aspects, the method may further comprise actuating an alarm. In some aspects, the detected water level may exceed a predetermined threshold value. In accordance with one or more embodiments, a method of waterproofing a basement may comprise retrofitting a basement waterproofing system with a solid state water level sensor as described herein. In accordance with one or more embodiments, a method of controlling water in a boat bilge may comprise connecting a switch as described herein to a bilge pump in the boat bilge. The disclosure contemplates all combinations of any one or more of the foregoing aspects and / or embodiments, as well as combinations with any one or more of the embodiments set forth in the detailed description and any accompanying examples. Docket No. D2013-7005WO BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings: FIG. 1 presents an operational schematic of a solid state water level sensor in accordance with one or more embodiments; FIG. 2 presents a schematic of a solid state water level switch in accordance with one or more embodiments; FIG. 3 presents a schematic of a basement sump pump control system in accordance with one or more embodiments; and FIG. 4 presents a schematic of a timing task loop for a controller in accordance with one or more embodiments. DETAILED DESCRIPTION In accordance with one or more embodiments, a solid state water level sensor may provide enhanced reliability. Beneficially, the disclosed sensors may be significantly less susceptible to failure due to wear and tear, operating seamlessly without any moving parts. The sensors may be associated with a high level of measurement accuracy based on solid state technology. In accordance with one or more embodiments, the sensors may be integrated into various universal pump switches. The switches may be implemented with simple setpoint adjustment. The switches may include high water override protection. In at least some embodiments, the water level sensor may be integrated into a basement sump pump switch. In at least some embodiments, the water level sensor may be integrated into a marine bilge pump switch. The switches may, in turn, be integrated into advanced pump control systems, such as a basement sump pump control system for basement waterproofing. In accordance with one or more embodiments, water level sensors and related switches are disclosed which are based on solid state technology. Specifically, the disclosed water level sensors and related switches involve differential pressure analysis to accurately detect water level. Docket No. D2013-7005WO FIG. 1 presents an operational schematic of a solid state water level sensor in accordance with one or more embodiments. Sensor 100 includes column or pipe 110 which is intended to be positioned in a reservoir 120 configured to collect undesired water. In some non-limiting embodiments, the column or pipe 110 may be one inch in diameter. Differential pressure sensor 150 is connected to first tube 130 and second tube 140 at their first ends. In some non-limiting embodiments, differential pressure sensor 150 may be sensitive to detecting pressure differences down to at least below about 1 psi. A distal (second) end of tube 130 is in communication with ambient air. A distal (second) end of tube 140 is in communication with an isolated headspace 115 in column or pipe 110. Isolated headspace 115 includes air that is compressed via any rising water level within column 110. In operation, any undesired rising water level within reservoir 120 will also occur within column 110. The sensor includes backup conductivity sensors 160 for detecting high water in reservoir 120. FIG. 2 presents a schematic of a solid state water level switch in accordance with one or more embodiments. Water level sensor 100 may be integrated into switch 200. Switch 200 may generally be in communication with pump 270. In at least some embodiments, all associated electronics may generally be positioned in upper compartment 290 of water level switch 200 and embedded in waterproof epoxy. Two tubes, as described above, are used to bring the ambient and headspace air pressures to the sensing circuit of the differential pressure sensor. The two tubes may generally run through the sealant. The epoxy not only seals the top of the column or pipe making it airtight, but also serves as a heat sink for the electronics as well. Switch 200 may send a control signal to pump 270 when any detected water level exceeds a threshold level. In some embodiments, the threshold level may be controlled via simple positioning or placement of switch 200 in the reservoir such that any detected water level activates switch 200 to control pump 270. In other embodiments, a threshold water level may be predetermined and switch 200 may be programmed accordingly to control actuation of pump 270. In accordance with one or more embodiments, a pump switch may be a solid state pump switch as described herein. The solid state pump switch may provide better performance and efficiency than conventional water level pump switches, such as float switches which involve moving parts that are susceptible to corrosion, clogging and damage. In accordance with one or more embodiments, accurate analogue solid state water level sensing may be implemented. A solid state water level sensor may be polled up to multiple times Docket No. D2013-7005WO a second and transmit water level information in the reservoir, e.g. sump pit, in a serial data format, accurate to within at least about 0.1 inches. In non-limiting embodiments, the sensor may use a standard CAT5 cable and I2C data communication format. Two signals (clock and data) may be transmitted on request down a twisted pair of cable length 5'. In some embodiments, the data being sent is temperature compensated differential pressure. Pressure may be measured on both the inside of a 1 inch pipe and the outside atmosphere. The air in the upper portion of the pipe may be compressed by a rising water level. This temperature compensated pressure is directly proportional to water level. One inch of water (or any low viscosity liquid) will increase the inside pipe air pressure by .036 PSI. This is temperature compensated using the formula PV = nRT. In accordance with one or more embodiments, the solid state switch using data output from the solid state water level sensor may calculate any water level within the reservoir to within 0.1 inches multiple times per second. For the most part gasses all follow the equation: PV = nRT which can also be written where P is pressure (in atm), V is volume (in liters), n is number of moles and T is temperature (in K). R is a constant and is equal to 0.08206 L atm / moleK. In accordance with one or more embodiments, this principle is applied differently to calculate water level using the volume of air a column of water displaces in a pipe. Beneficially, it works better than conventional or alternative techniques (e.g. infrared or ultrasonic) to measure water level such as in the adverse dirty environment of a sump pit. The pressure in a column of water is 1PSI for every 2.31 feet of water in height. In some non-limiting embodiments, a 10 inch pipe may be used to measure an analogue water level. The volume of air is compressed to exactly match the column of water or water depth. The air pushes on the water with equal and opposite force, so that the air pressure in the volume of pipe is exactly equal to the depth of water from the bottom of the pipe. Thus, there is a linear, indirect measurement of water level by taking pressure measurements of the air at the top of the pipe. In accordance with one or more embodiments, differential pressure analysis involving sampling the atmosphere may be beneficial for negating error sources like temperature and changes in atmospheric conditions. Docket No. D2013-7005WO In accordance with one or more embodiments, the circuit may use a low cost solid state sensor and convert pressure into a voltage output. The error sources of temperature, volume, drift, and offset are taken out in the controller circuit and embedded firmware. The pressure inside the pipe is always less the 1 PSI ( .0360 / inch) of water depth. Some very significant advantages of the present technique are very little air volume is needed to make the measurement, no big mechanical diaphragm is needed to move a switch, several low cost 1 PSI pressure sensors are available on the market place, the pipe volume and debris that tends to be in the water does not effect the pressure therefore the measurement, it is now possible to measure analogue water level and verify water is actually flowing in pipes as well as seasonal water pumping volumes, and more accurate and remote set point control. Beneficially, many expensive and time-consuming site visits may be avoided. FIG. 3 illustrates a pump control system in accordance with one or more embodiments. Pump control system 300 may include a smart controller 380 and a solid state pump switch 200 as disclosed herein. Smart controller 380 may be in electrical communication with pump 270. In accordance with one or more embodiments, the pump control system may provide an alert in connection with any potential system malfunction including but not limited to a faulty pump, a faulty switch, power loss and / or sensor failure. The controller may be easy to install, without the need for a computer or smart device. Robust default settings may facilitate setup. The controller may provide notice and / or intervention in connection with any system fault. Beneficially, flooding, e.g. basement or bilge flooding, may be prevented under any and all conditions. The controller and water level sensor will operate the pump under any conditions. A lack of moving parts may provide greater longevity and increased reliability. Maintenance schedule alerts may be provided. A battery backup may provide continuity of operation in the event of a power outage. A serial interface may allow for configuration and optional add-on functionality. Firmware water level trip points may be set within the controller and can be externally programmed and controlled. These points can be used to turn the pump on / off at any water level along the pipe. Default values of where the sump pump is turned on and off may be set for the nominal vertical switch positions. With proper placement in the sump pit liner, no “trip point” values need changing. In some embodiments, an easy to use and / or tool-less bracket may be used Docket No. D2013-7005WO to quickly mount the vertical water level sensor. A few configurations will accommodate most mounting requirements. As a “fail safe” mechanism, two conductivity brass probes protruding from the epoxy top section may be optimized to sense the conductivity of water. The sensitivity of these probes are adjusted independently in both an analog and micro-controller based polling circuit. In the unlikely event of a pressure circuit failure, water will hit the tip of these probes and complete the circuit. An analogue hardware circuit will activate a solid state switch as well as a parallel digital process controlled by firmware and the micro-controller. Triple protection is in place to ensure the sump pump turns on in the event of a high water level. The electronics is checking the water level and potential sensor failure up to multiple times in one second. In accordance with one or more nonlimiting embodiments, the controller uses a 16 bit MicroChip Pic24 based micro-controller. It uses a standard I2C bus for both water level sensing and communication to non-volatile memory. If communication with this water level sensor stops for any reason (e.g. cable severed, pressure sensor error, electrical noise error) it is considered a “Red Alert”. Red LED will blink at a unique rate and a unique audio sound will signal problems or an error detected. A Tri-color LED located on the upper left hand controller unit may be used to display system conditions and various alerts. A push button on the right hand corner may be used to implement the “test mode” and / or a silent mode (e.g. 12 hour) so that once an alert notification is given the customer can silence the audio alert (LED alerts still happen) for a 12 hour period. If the button is held for more than a predetermined period of time (e.g. six seconds) it may reset the system with the use of a watchdog timer (WDT) interrupt. The test mode can be used for a complete system check after an installation and may only be about ten seconds in length. During a test, pump current is checked to be in range of both lower and upper current set points. If outside this range alarm and LED alerts will be issued. Other example alerts are as follows:

[0002] Docket No. D2013-7005WO In some embodiments, the controller's internal timer synchronization routine is set via a 100 msec interrupt under hardware control. All events may be initiated and synchronized by this mechanism. This simplified interrupt driven timing loop is presented in FIG. 4. Any “book keeping” functions that are needed for operation are initiated by this timing task loop. Care must be taken if future firmware modification are made not to exceed the capacity of the micro- controller or this timing loop. The green light blinking is a functional relationship of this timing loop working properly. The rate of this green light is derived from completion of this loop, so the rate of blinking indicates proper operation. Single point failure components like the internal 5V power module and the solid state Triac switch circuit are protected with two levels of surge protection. These single point failure components have been considered in a continuous improvement design process. The firmware may run in a continuous loop resetting the clock / hours every 10 days. Total pump cycles & pump hours are stored in nonvolatile memory. This memory has been enhanced and may retain data every cycle and every sec of pump “ON” time. Nonvolatile data retention may exceeds ten years. Docket No. D2013-7005WO Various non-limiting details of representative systems are presented below. Pump Current Measure: Pump current is measured in terms of percentage of a 10A (AC) full scale. It now only takes 16msec (one 60 Hz cycle) to measure the current. The circuit uses a hall effect sensor to detect current flow. This current flow is used to determine pump condition and system functionality. Water Level Sensing: Typical water level sensing is accomplished by measuring differential pressure in the manor explained in the first section. Readings are taken at a rate of two times a sec. A running average of 4 samples are taken and converted to water level within 0.1 inches. After each sample it is determined if the pump should be turned on or not. Once the Pump is turned on a minimum of a 5 Sec dwell time in programmed into the controller. This minimum dwell time helps the pump get up to full speed and a stable current measurement load. It also helps prevent short cycling the pump to prevent pump burn out. Therefore the pump shuts off when two conditions are met; both a lower water level trip and the 5 sec dwell time is reached. High Water Override: This is a state of the art mixed signal circuit. It has an analog conductivity detection circuit with two 1 / 8 inch brass probes on the corners of the top of the water level sensor. Brass is of course a metal resistant to corrosion around water and remains conductive for many years. If the primary water level sensor fails this is a two level back up switch sensor. It has both an analog component and a micro-controller polling component. A low level voltage potential is applied to the brass probes, water completes the circuit being partially conductive even will various contaminants dissolve in it. Two parallel mechanisms are employed to ensure pump “turn on” in the event of primary pressure failure. Method One: the processor polls the condition twice a second. If high water is detected the processor turns on the pump for 20 seconds. Method Two: In case of both processor failure and pressure sensor failure there is an analog circuit that charges up a 10uf Capacitor that will turn on the pump switch as well. The timing of this circuit is set to keep the pump on for about 10 sec. If the processor is functional (the most likely Docket No. D2013-7005WO situation) this analog circuit will not come into play. It is simply a backup for the existing High Water Override. This system gives 3 levels of protection against system failures. Push Button Control: The high quality push button is used to implement three functions and is polled by the micro-controller on a periodic basis. An audible indication is used so the user is aware of what function is implemented. 1: Short Push: 10 Sec System test, pump current is measured and verified that the current value is in between high and low Set Points (indicated by first high chirp and violet blinking light) 2: Long Push Silent Mode; No audible alarms for a 12 hour period. (indicated by a second low chirp) 3. Button held down: until restart audible tones are heard. System reset silent mode off and system is reset. Serial Port: system currently has a standard serial port currently operating at 9600 BAUD; this is used to change or modify set points, trip points, testing frequency and many other parameters. It also can be used to retrieve data points like cycle count, pump hours, firmware level and many other parameters. It is hoped that for most installations the default values will work for all these parameters. Commands are in standard ASCII and are 3 characters followed by one of two parameters delimited by commas. Therefore, a terminal emulator program can be used to configure each unit. This would be helpful in testing. In some embodiments, control of an inverter, WIFI interface or blue tooth devices, or external temperature / humidity sensor(s) may be incorporated. A cable interface to an IPAD with an easy to use APP may also be implemented for configuration and data retrieval purposes. Status LED: A standard tri-color LED; RED, BLUE, GREEN to indicate alarm status and proper system operation. The blink rate and color mixing is controlled via the micro controller. Docket No. D2013-7005WO Automatic System Test: Automatic testing is performed on a periodic basis and can be changed by the command string STF, X, were X is an ASCII 1 – day, 2- 3day, 3 -week, 4 -hour, 5 – No Test. The default setting is “one week”. The test involves measurement of pump current and verifying it is between both upper and lower Setpoints. The water level sensor is tested every sec. A failure will generate a “RED” alert and audible indication as indicated in chart #1. WDT Watch Dog Timer: This is a hardware driven timer that insures the program is always running the planned code. If the timer is not reset / cleared once every 4.9 sec it automatically generates a hardware reset and brings the processor back on course. The push button (if held down long enough) uses this timer action to reset the system. Battery Backup: Under the front cover is a battery pack consisting of 3 AAA batteries. These batteries will only be used in case of AC power loss. It will sound an alarm and indicate AC power out. It will also operate a high water alarm. Battery usage will be dependent on how often AC power goes out. Audible Beeper: The audible tone is used along with the status LED to indicate a variety of issues. The pitch is under firmware control and the driving frequency works in parallel with the program and does not use CPU cycles. This is efficient and increases reliability. Maintenance: The electronics portion of the system should not need any maintenance for many years. It is envisioned that the circuit board may be conformally coated to further increase protection from water after the units have been in the field a while. The filler pipe portion of the water level sensor can be periodically cleaned. The accuracy of this sensor will not be affected by any debris provided complete blockage of the bottom end of the pipe or the small tube (Not exposed to water) on the top end happens. If this is the case the high water sensor will still function. Simple tools are available to clean out this 1 inch diameter pipe allowing any debris to fall out the bottom. In accordance with one or more embodiments, the disclosed solid state switches and control systems may replace conventional switches, e.g. horizontal or vertical switches, in a wide Docket No. D2013-7005WO range of applications. A USB controlled inverter, low cost “in the pit” switch, IOT interface, Dual channel and other features may be incorporated to supplement the functionality. Apart from basement waterproofing systems, application may be found in other industries such as but not limited to fan monitoring for the radon marketplace and sewage flow control. In accordance with one or more embodiments, the pump control system may specifically be a basement sump pump control system. The basement control system may function as a service technician in a box. An advanced sump pump controller may automatically check and monitor a sump pump system. Intelligent monitoring ensures undisrupted protection against basement flooding, even in the event of a power outage. In accordance with one or more embodiments, a basement control system may include additional functionality such as control of a fan for humidity and / or radon control. In accordance with one or more embodiments, a basement control system may be one as described in U.S. Patent Application Publication No. 2022 / 0349398 which is commonly owned by Applicant and which is hereby incorporated herein by reference in its entirety for all purposes. In accordance with one or more other embodiments, the pump control system may specifically be a marine bilge pump control system. The phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. As used herein, the term “plurality” refers to two or more items or components. The terms “comprising,” “including,” “carrying,” “having,” “containing,” and “involving,” whether in the written description or the claims and the like, are open-ended terms, i.e., to mean “including but not limited to.” Thus, the use of such terms is meant to encompass the items listed thereafter, and equivalents thereof, as well as additional items. Only the transitional phrases “consisting of” and “consisting essentially of,” are closed or semi-closed transitional phrases, respectively, with respect to the claims. Use of ordinal terms such as “first,” “second,” “third,” and the like in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements. Docket No. D2013-7005WO Having thus described several aspects of at least one embodiment, it is to be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. Any feature described in any embodiment may be included in or substituted for any feature of any other embodiment. Such alterations, modifications, and improvements are intended to be part of this disclosure and are intended to be within the scope of the invention. Accordingly, the foregoing description and drawings are by way of example only. Those skilled in the art should appreciate that the parameters and configurations described herein are exemplary and that actual parameters and / or configurations will depend on the specific application in which the disclosed methods and materials are used. Those skilled in the art should also recognize or be able to ascertain, using no more than routine experimentation, equivalents to the specific embodiments disclosed. What is claimed is:

Claims

Docket No. D2013-7005WO CLAIMS 1. A solid state water level sensor, comprising: a differential pressure sensor; a column configured to sit in a reservoir intended to collect undesired water; a first tube having a first end and a second end, the first end connected to the differential pressure sensor and the second end in fluid communication with a source of ambient air; and a second tube having a first end and a second end, wherein the first end is connected to the differential pressure sensor and the second end is in fluid communication with an isolated headspace above any water level present in the column.

2. The sensor of claim 1, wherein the differential pressure sensor has a sensitivity down to at least as low as 1psi.

3. The sensor of claim 1, further comprising a backup conductivity sensor.

4. A solid state water level switch comprising the sensor of claim 1.

5. The switch of claim 4, further comprising a processor in communication with the differential pressure sensor, wherein the sensor is configured to communicate differential pressure data to the processor and the processor is configured to correlate the differential pressure data to a reservoir water level.

6. The switch of claim 5, wherein the processor is a controller configured to actuate a pump in response to the reservoir water level exceeding a threshold level.

7. The switch of claim 6, wherein the switch is a TRIAC switch.

8. A water level control system comprising the switch of claim 5 and a pump in communication with the switch.Docket No. D2013-7005WO 9. The system of claim 8, wherein the pump is a basement sump pump for basement waterproofing.

10. The system of claim 8, wherein the pump is a marine bilge pump.

11. The system of claim 8, wherein the pump is associated with sewage control or radon control.

12. A method of detecting a water level in a reservoir, comprising: detecting an ambient pressure level in an environment; detecting a pressure level in an isolated headspace above any undesired water present in the reservoir; performing differential pressure analysis between the ambient pressure level and the isolated headspace pressure level; and correlating the differential pressure analysis to a water level in the reservoir.

13. The method of claim 12, wherein the reservoir pertains to a basement sump.

14. The method of claim 12, wherein the reservoir pertains to a marine bilge.

15. The method of claim 12, further comprising supplementing detection by monitoring a conductivity level in the reservoir.

16. A method of controlling a water level in a reservoir, comprising: detecting a water level in the reservoir according to claim 12; and actuating a pump in response to the detected water level.

17. The method of claim 16, further comprising actuating an alarm.

18. The method of claim 16, wherein the detected water level exceeds a predetermined threshold value.Docket No. D2013-7005WO 19. A method of waterproofing a basement, comprising: retrofitting a basement waterproofing system with the solid state water level sensor of claim 1.

20. A method of controlling water in a boat bilge, comprising: connecting the switch of claim 4 to a bilge pump in the boat bilge.

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