Pneumatic indicator for detecting liquid level

A pneumatic sensor/indicator device includes a sensor assembly having a bellows receiving chamber and sensor housing. An elastic bellows is in the bellows receiving chamber. A shaft connects to the bellows so bellows extension/retraction causes shaft axial movement. A magnet connected to the shaft generates a field moving an indicator ring. An indicator dome connects to the sensor body. The indicator ring is in the sensor housing in a non-indicating condition and displaces into the indicator dome providing a visible indicating condition. A flexible sensor tube connected to the sensor/indicator device extends into a well tube having a level sensing tube extending therefrom. A well fluid level rising above a level sensing tube inlet end increases inlet pressure port pressure inducing bellows axial displacement causing indicator device movement toward the indicating condition. The dome and indicating ring are isolated from the well preventing well contents entering and fogging the dome.

FIELD

The present disclosure relates to fluid level sensing devices.

BACKGROUND

In groundwater wells, landfill gas, landfill leachate recovery wells and condensate recovery wells, hereinafter generally referred to as “wells”, there is a need to monitor liquid level in the well. If liquid level exceeds a preset level, action may be required to lower the liquid level so that methane recovery is not impacted. This may involve installing a pump, repairing an existing pump, adjusting vacuum levels, adjusting gas flow, and the like. Well liquid level status should be measurable without impacting the well environment. Well environments may be hazardous because of flammable gasses such as methane in the well, or chemicals in the leachate that corrode or damage test equipment, therefore use of electronic measurement devices directly in the well may be precluded. Measurement systems that require the well to be opened for manual liquid level measurement are also undesirable, particularly in wells operating under a vacuum to prevent outside air entering the well during a liquid level monitoring event. In addition, opening the well for liquid measurement can by itself affect the liquid level, and can further adversely impact methane recovery in methane recovery wells.

SUMMARY

According to several embodiments, a pneumatic sensor/indicator device includes a sensor assembly having a bellows receiving chamber created in a sensor housing, an inlet pressure port, and a reference port. An elastic bellows is positioned in the bellows receiving chamber. The bellows has an inner chamber isolated from the bellows receiving chamber and in communication with the inlet pressure port. The bellows receiving chamber external to the bellows is in communication with the reference port. An indicator dome connected to the sensor body. An indicator member is positioned in the sensor housing in a non-indicating condition and is axially displaced by an extension of the bellows into the indicator dome in an indicating condition where the indicator member is visible through the indicator dome.

According to other embodiments, a pneumatic sensor/indicator device includes a sensor assembly having a bellows receiving chamber created in a sensor housing. An elastic bellows is positioned in the bellows receiving chamber. A shaft is connected to the bellows such that extension or retraction of the bellows causes axial movement of the shaft. A magnet is connected to a connecting end of the shaft. An indicator dome is connected to the sensor body. An indicator member is positioned in the sensor housing in a non-indicating condition and is axially displaced into the indicator dome in an indicating condition where the indicator member is visible through the indicator dome.

According to additional embodiments, a flexible sensor tube connected to the sensor/indicator device extends into a well tube. A level sensing tube extends from the flexible sensor tube. A well fluid level rising above an inlet end of the level sensing tube thereafter increases inlet pressure port pressure inducing bellows axial displacement, causing the indicator member to reposition from the non-indicating condition toward the indicating condition. The indicating member is moved by a magnet so the indicating member can be isolated from the environment in the well to prevent contents of the well from condensing in and/or fogging the indicator dome. A reference port is provided so that the sensor/indicator device functions at atmospheric pressure, at vacuum pressure, or at pressures above atmospheric pressure.

DETAILED DESCRIPTION

Referring toFIG. 1, a sensor system10includes a pneumatic level sensor assembly12which is either directly or indirectly connected to a well assembly14. Level sensor assembly12is provided to indicate the presence of an undesirable level of fluid16, such as leachate present in the well assembly14. Well assembly14can include a well tube18commonly made of a metal, such as steel, or a plastic material, such as PVC. Well tube18commonly has an exposed well portion20positioned above a ground surface22and a buried well portion24positioned below the ground surface22. Buried well portion24can extend from tens of feet to more than one hundred feet below ground surface22.

Level sensor assembly12includes a sensor/indicator device26which can be directly or indirectly connected to a well top28of well tube18. According to several embodiments, an inlet portion30of level sensor assembly12can be positioned at least partially within a well cavity32of well tube18. A sensor tube34, made for example of a thin-walled polymeric material, is connected to inlet portion30and extends for a predominant length of well tube18within both the exposed well portion20and the buried well portion24. A level sensing tube36, commonly made of a metal material such as stainless steel, is connected at a lower end of sensor tube34. A length of level sensing tube36is predetermined such that fluid16within well cavity32, which substantially fills level sensing tube36, provides a visual indication or alarm in an indicator portion38of level sensor assembly12.

Level sensing tube36is positioned within buried well portion24such that a tube inlet end40is positioned above a well tube lower end41at a distance from well tube lower end41that permits fluid16entering through a plurality of fluid inlet apertures42created through buried well portion24to reach an anticipated or normal liquid high level43which does not contact the tube inlet end40. When fluid16in well cavity32is at or below the normal liquid high level43, no visual indication is provided by indicator portion38of level sensor assembly12. When fluid16rises within well cavity32and contacts tube inlet end40or rises above tube inlet end40, for example to a sensed liquid level44, the air/gas mixture contained within liquid level sensing tube36and sensor tube34is compressed, which causes a visual indication of this level change to be visible at indicator portion38. As the level of fluid16in well cavity32rises toward a tube upper end45of level sensing tube36, indicator portion38of level sensor assembly12visually indicates an increasing level alarm condition by further visual exposure of indicator portion38. The indication point is a function of a length of sensor tube34and a length of liquid level sensing tube36. According to several embodiments, the length of liquid level sensing tube36is approximately 45.7 cm (18 inches). The full or any intermediate level alarm condition can be seen by an operator monitoring sensor system10and provides a visual indication that the level of fluid16within well cavity32is above a desired level. The operator can then take remedial measures, such as operating a fluid pump, to reduce the level of fluid16within well cavity32back to the normal liquid high level43or below. The pump (not shown) can be operated until all visual indication of the fluid level indicated at indicator portion38is removed.

It is desirable to maintain the level of fluid16within well cavity32at or below the normal liquid high level43such that fluid and gas can enter the plurality of fluid inlet apertures42for subsequent removal of the gas, such as methane for methane recovery, from well cavity32. High levels of fluid16within well cavity32can block the plurality of fluid inlet apertures42and can also be an indication of high water levels in the ground area surrounding well assembly14, which can lead to erosion or well collapse. Level sensor assembly12operates entirely from a differential pressure sensed between fluid16within level sensing tube36and the pressure (normally a vacuum pressure) maintained within well cavity32. Level sensor assembly12requires no outside power and provides a visual indication of an alarming condition.

Referring toFIG. 2, if the operator monitoring well assembly14sees a visual indication of a high liquid level by displacement at the indicator portion38, the operator can take further remedial steps to determine the actual fluid level within well cavity32. For example, the operator can connect a control/measurement device46to well assembly14via connections provided with level sensor assembly12. Control/measurement device46, according to several embodiments, can include a compressor assembly48which provides a source of pressurized air to a pressure regulator unit50. Compressor assembly48is commonly provided with its own power source, such as a battery (not shown) and a compressor (not shown), which is operated by an on/off switch52. A pressure indication meter54can be provided to provide visual indication to the operator of the compressor pressure. Compressed air is supplied by compressor assembly48via an air supply line56and a tubing connector58to pressure regulator unit50. The pressurized air received in pressure regulator unit50is reduced to a desirable pressure (e.g., approximately 30 psi or another predetermined pressure) which is provided via an air bubbler sensing line60to a differential pressure measurement device62, such as a manometer. Differential pressure measurement device62can be connected and portably released from pressure regulator unit50and can be releasably stored using a storage housing64connected to pressure regulator unit50. The regulated pressurized air is also provided from pressure regulator unit50via an air bubbler line66to an air bubbler connection port68of level sensor assembly12. A well atmosphere reference line70, connected between a reference port72of level sensor assembly12and differential pressure measurement device62, provides a reference pressure of well cavity32. A differential pressure measured using differential pressure measurement device62between air bubbler connection port68and well atmosphere reference line70, given the known pressurized air pressure provided by pressure regulator unit50, provides an accurate indication of the actual level of fluid16above tube inlet end40. The connection of air bubbler line66to air bubbler connection port68and the connection of well atmosphere reference line70to reference port72is by quick connect minimally invasive connectors such that the vacuum normally present in well cavity32is minimally affected by the connection of these tubes. This reduces the possibility that connection of control/measurement device46to well assembly14will itself significantly alter the level of fluid16within well cavity32.

Referring toFIG. 3, sensor/indicator device26includes a sensor housing74having a housing flange76which is mechanically and releasably connected to an inlet portion flange78of inlet portion30. The releasable connection between housing flange76and inlet portion flange78allows for disassembly of sensor/indicator device26for maintenance, or to replace sensor/indicator device26. Sensor housing74, according to several embodiments, is made of a molded polymeric material and can further include a housing extension80integrally molded with sensor housing74. Indicator portion38can include a transparent or semi-transparent indicator dome82releasably connected to housing extension80. A sensor tube connector84is connected to inlet portion30and is provided for mechanical connection to sensor tube34shown inFIG. 1. Air bubbler connection port68is provided with inlet portion30.

Referring toFIG. 4, reference port72is oriented approximately 90° with respect to bubbler connection port68. A first plug86is shown threadably connected to reference port72to provide an atmospheric seal at reference port72. First plug86can be removed and replaced by a quick release fitting (not shown) when actual pressure measurements are taken via sensor/indicator device26.

Sensor/indicator device26further includes an indicator member87includes an indicator ring88made, for example, of a magnetically permeable material, such as steel, which is normally slidably disposed within housing extension80in a non-indicating condition shown. Indicator member87further includes an indicator label90affixed to an outer perimeter of indicator ring88. According to several embodiments, indicator label90is adhesively applied to indicator ring88and is orange or red in color to be readily visible when indicator label90is positioned within indicator dome82. Both indicator ring88and indicator label90attached to indicator ring88are slidably disposed within housing extension80and are axially movable with respect to a sensor longitudinal axis92. The non-indicating condition of sensor/indicator device26shown is provided when indicator member87has indicator label90and indicator ring88retracted within the housing extension80such that indicator label90is not visible to a user or operator from the outside of sensor/indicator device26.

Referring toFIG. 5and again toFIGS. 1 and 4, an alarm or indicating condition of sensor/indicator device26is shown. In the sensor indicating condition of indicator member87, indicator ring88and indicator label90axially displace in an indicator extending direction “A” such that indicator label90is visible through indicator dome82. This condition occurs when a high fluid level is present in the well assembly14. When the fluid level within the well assembly14decreases below the sensing capability of sensor/indicator device26, indicator ring88and indicator label90return in an indicator retracting direction “B” to the non-indicating condition shown inFIG. 4where no visual indication of indicator label90is present through indicator dome82.

Referring toFIG. 6, inlet portion flange78of inlet portion30has a flange face94into which a counter-bore96is created. Counter-bore96is sized to receive a seating flange98of a bellows100made from an elastic material such as a resilient polymeric material. Bellows100further includes a mounting ring102positioned at an opposite end with respect to seating flange98. A washer104and a clamp106can be slidably received over an outer diameter of mounting ring102and used to releasably fix mounting ring102about a perimeter of a mounting portion110of a sliding shaft108. Sensor housing74further includes a construction port111which can be sealed using a second plug86″. The purpose for construction port111will be described in greater detail in reference toFIG. 7.

With continuing reference toFIG. 6and again toFIG. 1, sliding shaft108is slidably disposed within sensor housing74and extends through housing extension80. According to several embodiments a first magnet112can be releasably fixed to a magnet end114of sliding shaft108using a fastener116connected in an installation direction “C” to magnet end114. According to further embodiments first magnet112is not used and the magnet end114of sliding shaft110can be itself magnetized. A stop member118made for example of a metal material includes a receiving aperture120which is sized to be slidably received over a mounting portion diameter122of sliding shaft108. A set screw124, threadably inserted through a threaded bore126of stop member118is inserted to releasably fix stop member118at a desired axial position along sliding shaft108. Stop member118is slidably positioned in housing extension80and provides a sliding stop for axial outward motion of sliding shaft108as best shown in reference toFIG. 7. An O-ring128is positioned in an O-ring groove130created in sliding shaft108at an approximate mid-point of sliding shaft108. One purpose of O-ring128is to create a fluid seal at the junction of sliding shaft108at its connection with bellows100to prevent gas or liquid entering bellows100from flowing into a tubular post132or indicator dome82. Tubular post132is externally disposed over a portion of sliding shaft108with respect to sensor longitudinal axis92and is threadably engaged at a post threaded end134to a female threaded portion of a housing extension inner wall161in housing extension80shown and described in reference toFIG. 7. Sliding shaft108can therefore axially move within tubular post132. As best seen inFIG. 7a face136of stop member118contacts the housing extension inner wall161defining the outward axial stop position of sliding shaft108. A second O-ring138is positioned in a second O-ring groove140created in tubular post132. Second O-ring138prevents fluid and/or gas on the exterior side of bellows100or from the well assembly14from migrating beyond tubular post132and into the internal space of indicating dome82, and thereby prevents fogging of indicating dome82.

The indicator ring88includes an inner bore142which is sized to be slidably received with respect to a post diameter144of tubular post132. Indicator ring88therefore can axially slide with respect to sensor longitudinal axis92about the post diameter144of tubular post132. As previously described, the indicator label90is attached, for example using an adhesive, to the outer perimeter of indicator ring88. Indicator label90can also be applied as a layer of paint to indicator ring88, or can be eliminated if indicator ring88is provided with a visual color such as orange or red. Indicator dome82further includes a third O-ring146seeded in a third O-ring groove148created in an outer perimeter surface150of indicator dome82. The third O-ring146, together with second O-ring138, provide atmospheric seals between perimeter surface150of indicator dome82and a housing inner bore152of housing extension80when perimeter surface150is slidably received in housing inner bore152. A passage seal member154is also provided with the assembly of sensor/indicator device26. The purpose for passage seal member154will be described in better detail in reference toFIG. 7. A plurality of sensor assembly fasteners156are inserted through apertures in inlet portion flange78to fastenably connect inlet portion30, using a plurality of internally threaded or self-threading fastener receiving tubes158, to sensor housing74. Bellows100is positioned substantially within sensor housing74when inlet portion flange78is either releasably or permanently coupled to housing flange76.

Referring toFIG. 7and again toFIG. 1, sensor/indicator device26is shown in an exemplary installed condition with respect to well tube18. Indicator dome82has an internal space159, and as previously noted, is a transparent or semi-transparent material. Indicator dome82can further include a conical apex160, which is provided to allow moisture and dirt to run off from the exposed upper surface of indicator dome82, thereby minimizing the adherence of materials which can block the visibility of indicator label90through indicator dome82. As previously noted indicator dome82is releasably engaged to housing extension80and hermetically sealed using third O-ring146. The tubular post132, slidably received within indicator dome82, is atmospherically sealed using second O-ring138in contact with a housing extension inner wall161of housing extension80so that material, gas or fluid of well cavity32cannot enter internal space159.

To simplify the following discussion of sensor/indicator device26, a well cap162is shown having inlet portion30in sealing contact therewith. It is anticipated that during normal use sensor/indicator device26will be connected using one or more apertures created in well cap162that permit the extension and sealing of sensor tube34independently with respect to well cap162, and therefore will provide a remote position for sensor/indicator device26with respect to well tube18and well cap162. With sensor tube34connected to sensor tube connector84as shown, a tubing inner bore164is aligned with an inlet pressure port166of inlet portion30. As fluid pressure within tubing inner bore164increases, caused by compression of the fluid/gas in level sensing tube36after fluid16contacts tube inlet end40, the pressurized fluid will travel from inlet pressure port166through a pressure passage168into a cylinder bore170of inlet portion30to contact a piston end172of sliding shaft110. Piston end172is slidably received within cylinder bore170such that sliding shaft110is axially movable with respect to sensor longitudinal axis92. A diameter of piston end172is less than an inner diameter of cylinder bore170such that a clearance path174is provided for the pressurized fluid or gas received within cylinder bore170to transfer between cylinder bore170and a bellows inner chamber176of bellows100.

A pressure P1in the inlet pressure port166substantially equals the pressure within bellows inner chamber176. A pressure P2in reference port72is substantially equal to a pressure in a bellows receiving chamber178that is external to bellows100. As pressure P1increases, pressure P1will exceed pressure P2in reference port72and therefore in bellows receiving chamber178that is external to bellows100. This differential pressure between pressures P1and P2across bellows100causes bellows100to axially extend within bellows receiving chamber178in the indicator extending direction “A”. Because clamp106releasably couples mounting ring102of bellows100to sliding shaft110, extension of bellows100also co-translates sliding shaft110in the indicator extending direction “A”. The axial extension of bellows100in the indicator extending direction “A” therefore displaces first magnet112, or if first magnet112is not used, the magnetized magnet end114of sliding shaft110, within tubular post132to the fully extended position shown. As first magnet112or the magnetized magnet end114of sliding shaft110axially translates in the indicator extending direction “A”, the magnetic field generated by first magnet112or the magnetized magnet end114magnetically pulls the indicator ring88and thereby the indicator label90in the indicator extending direction “A” until indicator label90is at least partially visible through indicator dome82.

Extension of bellows100in the indicator extending direction “A” continues until stop member118contacts extension inner wall161of housing extension80, defining a fully or maximum extended position of indicator member87. Indicator label90is fully visible through indicator dome82in the fully extended position. Indicator member87will remain in the extended condition until pressure P1reduces to or below pressure P2. It is noted that indicator label90will also be at least partially visible through indicator dome82as first magnet112axially translates between the retracted and maximum extended positions.

When the pressure P1within bellows inner chamber176reduces to either equal to or less than pressure P2, a weight of both sliding shaft110and stop member118pulls sliding shaft110with first magnet112in the indicator retracting direction “B” by the force of gravity until indicator ring88is returned to the retracted or non-indicating position shown in phantom as indicator ring88′. It is further noted that indicator label90will also be at least partially visible through indicator dome82as first magnet112axially translates back to the retracted position.

Housing flange76can further include a housing flange counter-bore180which is aligned with counter-bore96in an assembled condition such that seating flange98of bellows100is retained within both counter-bore96and housing flange counter-bore180to radially restrain seating flange98, while providing the compressive force required to hermetically seal seating flange98. Bellows inner chamber176is therefore isolated from a bellows receiving chamber178defined by sensor housing74. It is also noted that an upward travel limit for sliding shaft110and first magnet112is provided by stop member118when stop member118contacts housing extension inner wall161of housing extension80.

With further reference toFIGS. 1 and 7, further internal fluid flow paths are provided within sensor/indicator device26as follows. Bellows receiving chamber178is in fluid communication with well cavity32via the following path. A bellows chamber flow port182extends between bellows receiving chamber178and construction port111. Construction port111is provided such that bellows chamber flow port182can be created through the outer wall of sensor housing74. A bellows chamber connecting passage184is oriented substantially perpendicular to construction port111and bellows chamber flow port182. Bellows chamber connecting passage184is created through housing flange76and is coaxially aligned with a reference port connecting passage186created through inlet portion flange78. Reference port connecting passage186opens into reference port72. In turn, reference port72is connected, via a reference pressure passage188extending through inlet portion30, to well cavity32. The pressure within well cavity32, which can be maintained as a positive pressure or at a partial vacuum, is therefore present within bellows receiving chamber178, thereby providing a differential pressure between the higher pressure in bellows inner chamber176and the lower pressure within bellows receiving chamber178when fluid level within the well rises above tube inlet end40. A higher pressure P1within bellows inner chamber176, as fluid pressure increases within tubing inner bore164, provides the driving force for displacing sliding shaft110and first magnet112(or the magnetized magnet end114of sliding shaft110) and thereby provides visual indication of an increased fluid level within well cavity32as indicator ring88and indicator label90are magnetically upwardly displaced.

A bore end wall190is created at a lower end of cylinder bore170. Bore end wall190provides a positive stop for a lower end travel path of piston end172. Piston end172is provided and sized to maintain axial alignment of sliding shaft110during its sliding motion in the indicator extending direction “A” or the indicating retracting direction “B”. The passage seal member154is positioned between housing flange76and inlet portion flange78to seal the junction between bellows chamber connecting passage184and reference port connecting passage186. The sealing capability provided by seating flange98of bellows100and passage seal member154allows the installation of the sensor assembly fasteners156without requiring the use of additional seal members.

Referring toFIG. 8and again toFIG. 7, according to additional embodiments of the present disclosure, a sensor/indicator device200is modified from sensor/indicator device26by the inclusion of an inlet portion202releasably connected to sensor housing74′ and housing extension80′. An indicator dome204is modified from indicator dome82and further includes an indicator retainer assembly206slidably received in a conical apex208of indicator dome204.

Referring toFIG. 9and again toFIG. 7, indicator ring88′ and indicator label90′ are shown in their retracted or non-indicating condition positioned within housing extension80′. Indicator retainer assembly206is slidably disposed through an aperture210created in conical apex208. A second magnet212is fastenably connected to a retainer tube214which can extend above conical apex208by an extension height “D”. Second magnet212is therefore positioned within indicator dome204.

Referring toFIG. 10and again toFIGS. 7 and 9, when indicator ring88′ and indicator label90′ extend to the indicating condition above housing extension80′ and therefore within indicator dome204, indicator ring88comes within the magnetic influence of second magnet212. Second magnet212can thereafter retain indicator ring88′ and therefore indicator label90′ in the extended position (indicating condition) shown after the pressure P1within sensor/indicator device200reduces to pressure P2re-establishing the non-indicating condition. The use of second magnet212can thereby provide for a continuing indication of an alarm or high fluid level condition whether the high fluid level condition is sustained or not. This can provide indication to an operator that a high fluid condition has occurred at any time following a last inspection of sensor/indicator device200.

Referring toFIG. 11, further components of sensor/indicator device200include an O-ring211engaged with a retainer tube214, which seals aperture210at a junction between indicator retainer assembly206and conical apex208. A fastener216releasably couples second magnet212to retainer tube214having fastener216threadably engaged in a threaded aperture218of retainer tube214. A fastener head220of fastener216can contact a post end wall222of tubular post132′ when first magnet112′ is raised and positioned in its fully extended position in the indicator extending direction “A”. The indicator retainer assembly206allows retainer tube214to be axially slidable partially into the indicator dome204in a first position “E” (shown inFIG. 11) providing the indicating condition of indicator member87′ and slidable away from the sliding shaft110to a second position “F” (shown in phantom) releasing indicator member87′ for return to the non-indicating condition.

A vented plug224is seated in inlet pressure port166. Vented plug224can include a screened or filtered flow passage226which is provided to prevent passage of particulate matter into inlet pressure port166′. A reference pressure passage228in the normal operating mode of this embodiment is blocked from reference port72′. Reference port72′ is provided with a second vented plug230having a screened or filtered flow passage232similar to flow passage226of vented plug224. Reference port72′ is in fluid communication with construction port111′ via bellows chamber connecting passage184′ and reference port connecting passage186′. Reference pressure passage228is isolated from reference port72′ by use of a threaded connecting passage234having a threaded plug236installed therein. When threaded connecting passage234is blocked by threaded plug236, bellows receiving chamber178′ can be directly vented to atmosphere via construction port111′, bellows chamber connecting passage184′, reference port connecting passage186′, reference port72′, and flow passage232of second vented plug230. The differential pressure acting across bellows100′ is therefore the pressure within the flow passage226of vented plug224and atmospheric pressure at flow passage232of second vented plug230. The configuration ofFIG. 11having threaded plug236installed can therefore be used in well applications that contain flammable gas such as methane gas and/or that can be directly vented to atmosphere.

Referring toFIG. 12and again toFIG. 1, a sensor system238is modified from sensor system10and provides a pneumatic level sensor assembly12which is either directly or indirectly connected to a fluid tank240. Fluid tank240can be any type of fluid holding tank, including but not limited to sump tanks, sewage treatment tanks, sludge tanks, underground water runoff tanks that may be accessible by a man-way or manhole cover, and the like. Fluid tank240can include an outer wall242, a tank bottom244, and a tank top246. Level sensor assembly12can have the sensor/indicator device26directly or indirectly mounted to tank top246or tank outer wall242. Level sensing tube36is positioned within fluid tank240but a sensor tube248connecting level sensing tube36to sensor/indicator device26can be significantly shortened compared to sensor tube34to accommodate a height of fluid tank240.

An elevation of an inlet end252of level sensing tube36with respect to tank bottom244is chosen such that fluid entering level sensing tube36provides a visual signal at indicator portion38. When a changing fluid level in fluid tank240reaches a predetermined fluid level254, a high level indication signal is generated by a sensing device250. According to several embodiments sensing device250includes a reed switch which closes to send the high level indication alarm signal as an electrical signal to a control system256. The high level indication alarm signal can result from a predetermined differential pressure which corresponds to a difference between a first pressure in level sensing tube36as fluid reaches inlet end252and a second pressure corresponding to a water level reaching predetermined fluid level254. The high level indication alarm signal can also be based only on a predetermined pressure when a water level reaches predetermined fluid level254.

Control system256can be a program logic controller (PLC), a microcontroller, a datalogger, or similar device having a memory device259. The control system256receives the high level indication alarm signal257from sensing device250via a communication line258, and is pre-programmed to generate a corrective action signal266. In addition to the visual alarm condition provided at indicator portion38, the high level indication alarm signal257can also be sent to a remote site, for example by wireless transmission using a transmitter and antenna system260of control system256, or by a direct communication channel. Control system256can also incorporate an audible alarm261, or remotely trigger an audible alarm. The corrective action signal266can be for example an electrical signal forwarded from control system256to a fluid transfer device262via a communication path264. The fluid transfer device262can be a pump, a venturi flow device, an electrically operated valve, or a similar device which operates to discharge fluid from fluid tank240until a fluid level in fluid tank240drops below either the predetermined fluid level254or inlet end252. Control system256can compare the signal257to data in the memory device259to determine an approximate period of time for operation of fluid transfer device262based on fluid tank volume data stored, compare pressure signal data sensed by sensing device250to pressure data in memory device259, or trigger operation of fluid transfer device262which can include its own level detection device, float, or the like to determine itself when to stop operating.

Referring toFIG. 13and again toFIG. 12, according to further embodiments, a pneumatic level sensor/indicator device268is modified from pneumatic level sensor assembly12to incorporate sensing device250directly into a modified transparent or semi-transparent indicator dome270. A U-shaped switch272such as a reed switch extends from sensing device250to a position above and proximate to indicator member87″ when indicator member87″ is in the fully extended position shown.

Referring toFIG. 14and again toFIG. 13, switch272extends into an interior portion of indicator dome270. Switch272can extend to the longitudinal axis92′ of level sensor/indicator device268.

Referring toFIG. 15and again toFIGS. 13 and 14, switch272is positioned within an internal housing274created of the same transparent or semi-transparent material of indicator dome270when indicator dome270is molded, for example from an injection molding process. Internal housing274permits switch272to be removed from indicator dome270for service or replacement, and to seal the internal space159′ of indicator dome270from atmospheric contaminants. When indicator ring88″ of indicator member87″ is in the upward or extended position, switch272is activated which sends an electrical signal indicating a high fluid level condition via communication line258. Sensing device250is weather-proof and is partially received and retained in a cavity276created in indicator dome270.

Referring toFIG. 16, a remote sensing and operating system278using pneumatic level sensor/indicator device268includes the capability to remotely control operation of a pump/air compressor assembly280using a pump timer panel282remotely positioned from well cavity32′. Level sensor/indicator device268is mounted to well tube18′ and uses sensor tube34′ as previously described herein. Pump/air compressor assembly280delivers air pressure to operate an air driven pump284positioned in well cavity32′ to remove liquid such as leachate from well cavity32′. Air is delivered to pump284via a pump air line286which is connected to a pressure supply line288using a pump air solenoid valve290. Pump air solenoid valve290is electrically controlled using a signal from switch272via a signal line294and from a signal transmission line296from pump timer panel282. A second signal transmission line298from sensing device250is also connected to pump timer panel282.

Pump timer panel282, when receiving the high fluid level condition of well cavity32′ from sensing device250and switch272via second signal transmission line298, signals pump air solenoid valve290to open allowing compressed air from pump/air compressor assembly280to operate pump284. When indicator ring88′ moves downwardly away from switch272indicating the high fluid level condition is no longer present, the changed signal from switch272via pump timer panel282shuts pump air solenoid valve290. Pump timer panel282is one example of a control unit for remote sensing and operating system278. Pump timer panel282can also be replaced by a computer, a control chip/controller circuit, or similar logic device that can also remotely operate remote sensing and operating system278via a wireless transmission system as previously described herein, or via the Internet, so that an operator can monitor the fluid level status of multiple wells having multiple level sensor/indicator devices268.

Pneumatic level sensor/indicator devices26,200,268of the present disclosure offer several advantages. By providing an internally sealed indicator ring having an indicator label90connected thereto which is displaced by magnetic attraction with a magnet or magnetized shaft moving in response to a pressure differential within the well, a local visual indication of a high fluid level within the well is provided without requiring the well to be opened or exposed to atmospheric pressure, while also preventing materials, fluids or gas within the well from contaminating the indicator label90. By further use of an indicator retainer assembly206of the present disclosure, a high pressure or high fluid level indication occurring following a previous inspection will be retained such that the operator does not need to be present at the time the high fluid level occurs in the well. This provides the operator with the opportunity to conduct further tests to determine if high pressure in the well is a continuing condition warranting remediation or a condition that requires subsequent follow up. By further addition of an electrical switch or transmitter to the sensor/indicator devices or system, a remote sensing and well pump operating system can be controlled.

Pneumatic sensor/indicator devices of the present disclosure can also be used in an opposite manner, i.e., to provide visual indication of a falling fluid level in liquid storage tank. For this use and referring again toFIGS. 7 and 12, the presence of liquid in a liquid storage tank such as a cistern would be indicated by the visible presence of indicator member87in indicator dome82. Downward motion of indicator member87would thereafter provide visual indication over time of a decreasing volume of useable liquid in the tank. The condition when indicator member87is completely disposed within housing extension80would provide, for example, visual indication that the tank requires refill, or impending loss of liquid supply.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. For example, a “well” or a “fluid tank” as referred to herein can broadly include any fluid containing member in which a liquid level can be present and sensed by a sensor/indicator device of the present disclosure.