GB2149534A - Liquid level control system - Google Patents
Liquid level control system Download PDFInfo
- Publication number
- GB2149534A GB2149534A GB08329780A GB8329780A GB2149534A GB 2149534 A GB2149534 A GB 2149534A GB 08329780 A GB08329780 A GB 08329780A GB 8329780 A GB8329780 A GB 8329780A GB 2149534 A GB2149534 A GB 2149534A
- Authority
- GB
- United Kingdom
- Prior art keywords
- chamber
- outlet
- sensor
- control system
- pipe
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
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Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D9/00—Level control, e.g. controlling quantity of material stored in vessel
- G05D9/04—Level control, e.g. controlling quantity of material stored in vessel with auxiliary non-electric power
-
- E—FIXED CONSTRUCTIONS
- E03—WATER SUPPLY; SEWERAGE
- E03F—SEWERS; CESSPOOLS
- E03F1/00—Methods, systems, or installations for draining-off sewage or storm water
- E03F1/006—Pneumatic sewage disposal systems; accessories specially adapted therefore
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- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Public Health (AREA)
- Water Supply & Treatment (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Automation & Control Theory (AREA)
- Control Of Non-Electrical Variables (AREA)
Abstract
A liquid level control system has a temporary storage tank (1) which discharges via a suction pipe (3) and a vacuum operated discharge valve (4). A sensor (5) senses the level of liquid within tank (1) and is connected to a vacuum source via (20) and (1a). The sensor (5) applies vacuum to its outlet (22) when the liquid in the tank (1) exceeds a predetermined level. A controller (6) has first chamber (23) connected to the sensor outlet and second chamber (24) connected to atmosphere and separated by a diaphragm (25). An inlet to the second chamber (24) is connected to the vacuum source and the outlet is connected to the vacuum operated discharge valve (4) and installed by a valve member (34) coupled to the diaphragm (25). A conduit (32) extends through the diaphragm (25) and the end of the conduit (32) in the second chamber (24) is surrounded by a sleeve (31) which acts as a restrictor to provide a time delay during operation. <IMAGE>
Description
SPECIFICATION
Liquid level control system
This invention relates to a liquid level control system.
A known liquid level control system has a temporary storage tank into which liquid flows and an outlet pipe connected to a vacuum source through a main discharge valve. A liquid level sensor senses the level of liquid within the temporary storage tank and when it reaches a predetermined level causes the main valve to be opened so that under the action of the vacuum the liquid contained in the temporary storage tank is discharged through the valve. The sensor is connected to the valve through a control system is aranged to maintain the main valve open for a predetermined period once the liquid level reaches the predetermined value.
Such a liquid level control system is useful for the control of the flow of sewage and such a system is disclosed in British Patent Specification No. 1 408 993.
In the control system disclosed in British Patent
Specification No. 1 408 993, the control system employs a timing device as well as a spool valve and is relatively complicated and it is an object of this invention to provide a relatively simple liquid level control system.
According to this invention there is provided a liquid level control system comprising a temporary storage tank having an inlet for receiving liquid and an outlet for discharging liquid; a vacuum operated discharge valve whose inlet is connected to the outlet of the temporary storage tank and whose outlet is intended to be connected to a vacuum source; a sensor which is connected to sense the level of liquid within the temporary tank and which has an inlet intended to be connected to the vacuum source, and an outlet, the sensor being arranged to apply vacuum to the outlet when the liquid in the temporary storage tank exceeds a predetermined level; and a controller having a first chamber connected to the outlet of the sensor, a second chamber connected to atmosphere and separated from the first chamber by a movable seal, an inlet to the second chamber intended to be connected to the vacuum source, an outlet from the second chamber connected to the vacuum operated discharge valve, a valve member carried by the movable seal and co-operating with the inlet and outlet of the second chamber, a conduit which extends through the movable seal and has first and second ends in the first and second chambers respectively, the second end being surrounded by a restrictor in all positions of the movable seal, the valve member being movable between a first position in which it applies atmosphere to the outlet of the second chamber and a second position in which it connects the inlet and the outlet of the second chamber, and spring means for urging the movable to a position such that the valve member is in its first position, the application of vacuum to the first chamber serving to move the movable seal to a position such that the valve member is in its second position.
In use, whenever the liquid is below the predetermined level the sensor does not apply vacuum to the first chamber of the controller so that the spring means moves the movable seal to the position in which the valve member applies atmosphere to the discharge valve which therefore remains closed.
When the liquid reaches the predetermined level, vacuum is applied to the sensor to the first chamber of the controller so that the movable seal moves to the position in which the valve member applies vacuum from the inlet to the outlet of the second chamber. Vacuum is then applied to the discharge valve which opens allowing the liquid in the temporary storage tank to discharge through the discharge valve under the influence of the vacuum source.
When the liquid falls below the predetermined level the sensor ceases to apply vacuum to its outlet. As the second chamber is at atmospheric pressure air enters the second end of the conduit at a restricted rate because that end is always surrounded by the restrictor and flows through the conduit into the first chamber. The pressure of air in the first chamber gradually rises until it approaches atmospheric pressure when the spring means moves the valve member to the position in which atmospheric pressure is applied to the outlet of the second chamber.
The atmospheric pressure is therefore applied to the discharge valve which then opens the discharge valve.
The movable seal is preferably a diaphragm.
Preferably, the conduit of the controller is formed within a push rod which carries the valve member.
Preferably, the push rod is carried by a piston carried by the diaphragm.
Preferably, the restrictor is in the form of a sleeve which surrounds the push rod.
The reciprocating motion of the push rod within the restrictor itself has a cleaning action which is highly desirable.
The time taken for the valve member to move back from its second position to its first position upon the liquid in the temporary storage tank falling below the predetermined level is dependent in part on the force exerted by the spring means and that force is preferably adjustable.
Preferably, the sensor comprises third and fourth chambers separated by a second movable seal, the fourth chamber being at a fixed pressure, a pipe depending downwardly into the temporary storage tank so that as the liquid rises above the bottom end of the pipe the pressure in that pipe rises, said pipe being connected at its upper end to the third chamber, a snap action mechanism which carries a seal co-operating with the inlet or outlet of the sensor and a coupling member which couples the diaphragm to the snap action mechanism, the arrangement being that as the pressure in the sensor pipe rises, the second movable seal is moved so that the coupling member applies an increasing force to the snap action mechanism which is arranged to apply vacuum to the outlet of the sensor when the pressure in the sensor pipe exceeds a predetermined value corresponding to the predetermined level.
Preferably, the seal co-operates with the inlet of the sensor.
Preferably, the second movable seal is a diaphragm.
Preferably, the coupling member is adjustable in position in relation to the second movable seal.
This latter feature enables the predetermined pressure and the predetermined level to be adjusted.
Preferably, the fourth chamber is connected by a pipe to the second chamber.
Preferably, the vacuum operated discharge valve comprises fifth and sixth chambers separated by a movable seal carrying a valve member, the outlet of the second chamber being connected to the fifth chamber and the sixth chamber being connected to atmosphere.
A preferred embodiment of the invention has all the features set out above and it will be observed that the controller and the sensor do not use leak ports which are prone to blockage by dirt.
The outlet of the discharge valve is connected in use to the vacuum source and consequently has a force acting on it tending to close it. This is a desirable feature.
An embodiment ofthis invention will now be described, by way of example only, with reference to the accompanying drawings of which
Figures 1 and 2 are schematic fluid circuit diagrams in the conditions in which the level of liquid in a collection sump is below and above a predetermined level respectively.
Figure 1 shows a sewage flow system having a collection sump 1 into which sewage flows via an inlet pipe 2.
Sewage leaves the collection sump 1 via a suction pipe 3 under the control of an interface valve 4 which controls the flow of sewage through the pipe 3. A vacuum collection station is connected to the pipe 3 on the downstream side of the valve 4.
A sensor 5 serves to sense the level of sewage in the collection sump 1 and when it is above a predetermined level applies vacuum to a controller 6 which, in turn, causes the interface valve 4 to open so that sewage can flow through the pipe 3 to the vacuum collection station. The controller 6 is arranged to maintain the interface valve 4 open for a predetermined period once the sensor 5 detects that the level of sewage in the collection sump 1 exceeds the predetermined level.
In more detail, the sensor 5 is connected to a sensor pipe 7 which extends downwardly within the collection sump 1 and is broadened over most of its length within the sensor pipe 7. The upper end of the sensor pipe 7 is connected to a chamber 8 in the bottom of the sensor 5; chamber 8 is separated from a chamber 9 above it by a flexible diaphragm 10 which carries a flat piston 14 on its lower surface and an upwardly extending push rod 11. The chamber 9 is separated from a chamber 12 at the upper end of the sensor 5 by a wall 13 joined to the housing of the sensor 5. The push rod 11 is slidable within a closely fitting bore within the wall 13.
A snap action mechanism 15 is mounted at one end on a wall 16 which projects inwardly from the casing of the housing 5 and is generally similar to the mechanism of a snap action switch. At its other end the switch mechanism 15 carries a seal 17 which in the condition in which the level of the sewage in the sump 1 is below the predetermined level, engages the end of a pipe 18. This is the condition shown in Figure 1. When the level of the sewage in the collection sump 1 is above the predetermined level the snap action mechanism 15 is in its other position in which the seal 17 is separated from the end of the pipe 18 and rests against a back stop 21 integral with the housing of the sensor 5. The pipe is connected via a further pipe 19 and a surge tank 20 to the suction pipe 3 on the downstream side of the interface valve 4 and is therefore connected directly to the vacuum source.The sensor 5 has a back-stop 52 engaged by the mechanism when in its "other" position; back-stop 52 is in the form of a bolt screwed in to the housing 5.
A pipe 22 connects the chamber 12 of the sensor 13 to a chamber 23 of the controller 6. In the orientation of the controller 6 shown, connection of the pipe 22 is to the left-hand end of the controller 22. The chamber is separated from a further chamber 24 within the controller 6 by a diaphragm 25 which carries a piston 26 and a push rod 27. A compression spring 28 urges the piston 26 and the push rod 27 to the right. The left hand end of the spring 28 engages a plate 55 carried by a bolt 6 screwed into the housing 30 of the controller 6. Push rod 27 extends within an extension 29 of the housing 30 of the controller 6 and a slidable within a sleeve 31 with a restricted clearance. A longitudinal central bore 32 extends within the push rod 27 from the end communicating with the chamber 23 through approximately 40% of its length.At its inner end the bore 22 is provided with transverse air-ways 33 which extend to the surface of the push rod 27 and communicate with the clearance between the push rod 27 and the sleeve 31. Throughout the maximum possible movement of the push rod 27 from its maximum position to the right as shown in Figure 1 to its maximum position to the left as shown in
Figure 2 the air-ways 33 are within the sleeve 31. At its right-hand end the push rod 27 carries a valve member 34 which engages the surface of the extension 29 and is formed with a recess 35 between two lands 36. The space 37 within the extension 29 forms part of the chamber 24 and at all times communicate with atmosphere through a pipe 38.
The space 37 also communicates with the chamber 9 of the sensor 5 via a pipe 40 and is also connected via a pipe 39 to a chamber 41 of the interface valve 4 which will be described later. Further, the pipe 19 is connected to the extension 29. The positions of the connections of the pipes 19 and 39 to the extension 29 and the position of the valve member 34 are such that when the push rod 27 is in its most right-hand position the pipe 19 communicates with the recess 35 but is isolated by the lands 36 so that it does not communicate with the remainder of the space 37 nor with the entry to any other pipe. When the push rod 27 has travelled to its most left-hand position as seen in Figure 2, the recess 35 connects the openings of the pipes 19 and 39 but the lands 36 isolate these two pipes from any other part of the space 37.
The interface valve 4 has a diaphragm 42 which separates the chamber 41 from a further chamber 43 connected via a pipe 44 to the pipe 40. As the space 37 is always at atmospheric pressure so is the chamber 43. The diaphragm 42 carries a piston 44 which in turn carries a push rod 45. Push rod 45 extends through a plate 46 forming part of the housing of the interface valve 41 and carries a cylindrical valve member 47 slidable within a cylindrical valve guide 48 forming part of the interface valve 4. Valve member 47 co-operates with a valve seat 49 formed in the suction pipe 3. When the push rod 45 is extended downwardly as shown in Figure 1 valve member 47 engages valve seat 49 and prevents sewage flow through the pipe 3.In contrast, when the push rod 45 is retracted as shown in Figure 2 it moves valve member 47 away from valve seat 49 and sewage can flow through the suction pipe 3 under the influence of the vacuum connected to the suction pipe 3 as shown in Figure 2. A spring 50 urges the piston 44, the push rod 45 and the valve member downwardly.
The operation of the sewage flow system illustrated in the figures will now be described.
In the condition shown in Figure 1 in which there is very little sewage at the bottom of the collection sump 1, the bottom of the sensor pipe 7 is free of sewage and atmospheric pressure is applied to the chamber 8 of sensor 5. As chamber 9 is also at atmospheric pressure, diaphragm 10 with the piston 21 is. at its lowest possible position and the snap action mechanism is not engaged by the push rod 11. Accordingly the seal 17 carried at the end of the snap action mechanism 15 engages the end of the pipe 18 that vacuum is not applied through the surge tank 20, the pipe 19 and the pipe 18 to the chamber 12. Consequently, chamber 12 is at atmospheric pressure. The reason why chamber 12 is at atmospheric pressure is that air flows through the pipe 38 into the chamber 37 which is always at atmospheric pressure.The air flows through the restricted clearance between the sleeve 31 and the push rod 27 the air-ways 33, the bore 32, the chamber 23 and the pipe 22 into the chamber 12 which is thus at atmospheric pressure.
As chamber 23 is at atmospheric pressure as is chamber 24, the spring 28 pushes the piston 26 to the right to the maximum extent possible, i.e. the position shown in Figure 1 in which position as has previously been stated there is no connection between the pipe 19 and the pipe 39. Moreover, atmospheric pressure is applied from the chamber 37 to the pipe 39 so that the chamber 41 is at atmospheric pressure.
Consequently, both chambers 41 and 43 are at atmospheric pressure and the effect of the spring 50 is to push the valve member 47 against the valve seat 49 so that no sewage can flow through the suction pipe 3.
When sewage flows into the collector sump 1 via the pipe 2 to the extent that it covers the bottom of the sensor pipe 7, the pressure within the sensor pipe 7 begins to rise and this pressure is communicated to the chamber 8 and pushes the piston 14 and the push rod 11 upwardly. When the sewage has reached a predetermined level within the collection sump 1 the force applied by the push rod 11 against the snap action mechanism 15 is sufficient to cause it to carry out its snap action action moving the seal 17 away from the bottom of the pipe 18 and bringing the snap action mechanism 15 into engagement with the back stop 52 and also bringing the seal 17 into engagement with the back stop 21. The effect of uncovering the end of the pipe 18 is to apply vacuum to the chamber 12 and this vacuum is applied through the pipe 22 to the chamber 23.The effect of the vacuum in the chamber 23 is to move the piston 26 and the push rod 27 to the left against the action of the spring 28 to the maximum extent possible as is illustrated in Figure 2. The valve member 34 is of course also moved to the left and, as is illustrated in
Figure 2, connects the pipes 19 and 39. Consequently, vacuum is applied through the surge tank 20, the pipe 19, the recess 35 and the pipe 39 to the chamber 41 and this retracts the piston 44, the push rod 45 and the valve member 47 so that sewage can flow through the suction pipe 3 as is illustrated in Figure 2.
When the level of sewage in the collection sump 1 falls the effect is to move the piston 14 and push rod 11 downwardly and this has the effect of causing the snap action mechanism 15 to revert to its original position in which it closes the bottom end of the opening 18. Air begins to flow through the pipe 38 and the chamber 37 through the restricted clearance between the sleeve 31 and the push rod 27, the air-ways 33, and bore 32 into the chamber 23.
However, the clearance between the sleeve 31 and the push rod 27 is restricted, as has already been stated, so that there is a delay before the pressure of air in the chamber 23 rises to the extent that the spring 28 can push the piston 26 and the push rod 27 to the right. Until the pressure in the chamber 23 rises to atmospheric pressure the valve member 34 continues to connect the pipes 19 and 39 so that chamber 41 continues to have vacuum applied to it and the valve member 47 continues to be retracted.
When the pressure in the chamber 23 approaches atmospheric pressure, the spring 28 does push the piston 26 and the push rod 27 to the right to the position shown in Figure 1 whereupon atmospheric pressure is immediately applied through pipe 39 from the chamber 37 to the chamber 41. The spring 50 immediately pushes the valve member 47 to engage valve seat 49 cutting off the sewage flow.
As is illustrated the push rod 11 is adjustably secured to the piston 14 of the sensor 5 and adjustment of the position of the push rod 11 adjusts the pressure at which the sensor 5 operates the switch snap action mechanism 15.
Adjustment of the back stop 52 of the sensor 5 adjusts the pressure differential, i.e. adjusts the lower pressure at which the snap action mechanism 15 will revert to its original state in which the seal 17 closes the end of the pipe 18.
By adjustment of the bolt 56 the force applied by the spring 28 to the piston 26 may be adjusted and consequently the time taken for the chamber 23 to reach atomospheric pressure after closure of the end of the pipe 18 may be adjusted.
Claims (12)
1. A liquid level control system comprising a temporary storage tank having an inlet for receiving liquid and an outlet for discharging liquid; a vacuum operated discharge valve whose inlet is connected to the outlet of the temporary storage tank and whose outlet is intended to be connected to a vacuum source; a sensor which is connected to sense the level of liquid within the temporary storage tank and which has an inlet intended to be connected to the vacuum source, and an outlet, the sensor being arranged to apply vacuum to the outlet when the liquid in the temporary storage tank exceeds a predetermined level; and a controller having a first chamber connected to the outlet of the sensor, a second chamber connected to atmosphere and separated from the first chamber by a movable seal, an inlet to the second chamber intended to be connected to the vacuum source, an outlet from the second chamber connected to the vacuum operated discharge valve, a valve member carried by the movable seal and co-operating with the inlet and outlet of the second chamber, a conduit which extends through the movable seal and has first and second ends in the first and second chambers respectively, the second end being surrounded by a restrictor in all positions of the movable seal, the valve member being movable between a first position in which it applies atmosphere to the outlet of the second chamber and a second position in which it connects the inlet and the outlet of the second chamber, and spring means for urging the movable seal to a position such that the valve member is in its first position, the application of vacuum to the first chamber serving to move the movable seal to a position such that the valve member is in its second position.
2. A liquid level control system as claimed in claim 1 wherein the movable seal is a diaphragm.
3. A liquid level control system as claimed in claim 1 or claim 2 wherein the conduit of the controller is formed within a push rod which carries the valve member.
4. A liquid level control system as claimed in claim 3 as appendant to claim 3 wherein the push rod is carried by a piston carried by the diaphragm.
5. A liquid level control system as claimed in any of claims 1 to 4 wherein the restrictor is in the form of a sleeve which surrounds the push rod.
6. A liquid level control system as claimed in any of claims 1 to 5 wherein the sensor comprises third and fourth chambers separated by a second movable seal, the fourth chamber being at a fixed pressure, a pipe depending downwardly into the temporary storage tank so that as the liquid rises above the bottom end of the pipe the pressure in that pipe rises, said pipe being connected at its upper end to the third chamber, a snap action mechanism which carries a seal co-operating with the inlet or outlet of the sensor, and a coupling member which couples the diaphragm to the snap action mechanism, the arrangement being that as the pressure in the sensor pipe rises, the second movable seal is moved so that the coupling member applies an increasing force to the snap action mechanism which is arranged to apply vacuum to the outlet of the sensor when the pressure in the sensor pipe exceeds a predetermined value corresponding to the predetermined level.
7. A liquid level control system as claimed in claim 6, wherein the seal co-operates with the inlet of the sensor.
8. A liquid level control system as claimed in claim 6 ot claim 7, wherein the second movable seal is a diaphragm.
9. A liquid level control system as claimed in any of claims 6 to 8, wherein the coupling member is adjustable in position in relation to the second movable seal.
10. A liquid level control system as claimed in any of claims 6 to 9, wherein the fourth chamber is connected by a pipe to the second chamber.
11. A liquid level control system as claimed in any of claims 1 to 10, wherein the vacuum operated discharge valve comprises fifth and sixth chambers separated by a movable seal carrying a valve member, the outlet of the second chamber being connected to the fifth chamber and the sixth chamber being connected to atmosphere.
12. A liquid level control system substantially as hereinbefore described with reference to the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08329780A GB2149534B (en) | 1983-11-08 | 1983-11-08 | Liquid level control system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08329780A GB2149534B (en) | 1983-11-08 | 1983-11-08 | Liquid level control system |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8329780D0 GB8329780D0 (en) | 1983-12-14 |
| GB2149534A true GB2149534A (en) | 1985-06-12 |
| GB2149534B GB2149534B (en) | 1986-12-10 |
Family
ID=10551428
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08329780A Expired GB2149534B (en) | 1983-11-08 | 1983-11-08 | Liquid level control system |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2149534B (en) |
Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1989007293A1 (en) * | 1988-02-04 | 1989-08-10 | Cowells International Limited | Liquid level control system |
| EP0341595A1 (en) * | 1988-05-10 | 1989-11-15 | Harald Michael | Control device for a vacuum-actuated suction valve on a vacuum conduit, especially for sewage |
| GB2247327A (en) * | 1988-02-04 | 1992-02-26 | Euro Iseki Ltd | Liquid level control system |
| EP0550980A1 (en) * | 1992-01-07 | 1993-07-14 | Inax Corporation | Vacuum valve for a sewage collection system |
| EP0579815A1 (en) * | 1992-01-31 | 1994-01-26 | Burton Mech Contractors | Package system for collection-transport of waste liquids. |
| US5292104A (en) * | 1991-11-27 | 1994-03-08 | Ebara Corporation | Vacuum interface valve |
| EP0602604A1 (en) * | 1992-12-14 | 1994-06-22 | Ebara Corporation | Vacuum Valve |
| US5429068A (en) * | 1992-10-20 | 1995-07-04 | Fujitsu Limited | Deposition method for compound semiconductor forming device |
| US5588458A (en) * | 1994-04-19 | 1996-12-31 | Ebara Corporation | Vacuum valve controller for vacuum sewer system |
| US5615701A (en) * | 1993-06-07 | 1997-04-01 | Sekisui Kagaku Kogyo Kabushiki Kaisha | Vacuum valve control device and vacuum valve |
| EP0826838A2 (en) * | 1996-08-26 | 1998-03-04 | Ebara Corporation | Vacuum valve controller |
| EP1840282A2 (en) | 2006-03-31 | 2007-10-03 | Evac International Oy | Vacuum sewer system |
| WO2011066603A1 (en) * | 2009-12-03 | 2011-06-09 | Applidyne Australia Pty Ltd | Fluid control device and system |
| EP2415938A1 (en) * | 2009-04-03 | 2012-02-08 | Torishima Pump Mfg. Co., Ltd. | Control device for vacuum valve |
| DE102014100797A1 (en) | 2014-01-24 | 2015-07-30 | Bilfinger Water Technologies Gmbh | Arrangement for sucking off liquid |
| CN108980446A (en) * | 2018-08-31 | 2018-12-11 | 杭州电子科技大学 | A kind of lead button press switching device |
-
1983
- 1983-11-08 GB GB08329780A patent/GB2149534B/en not_active Expired
Cited By (33)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0519523A2 (en) * | 1988-02-04 | 1992-12-23 | Euro Iseki Limited | Valve control system |
| EP0519523A3 (en) * | 1988-02-04 | 1993-07-21 | Euro Iseki Limited | Valve control system |
| US5069243A (en) * | 1988-02-04 | 1991-12-03 | Euro Iseki Limited | Liquid level control system |
| GB2247327A (en) * | 1988-02-04 | 1992-02-26 | Euro Iseki Ltd | Liquid level control system |
| AU625990B2 (en) * | 1988-02-04 | 1992-07-23 | Euro Iseki Limited | Liquid level control system |
| GB2247327B (en) * | 1988-02-04 | 1992-09-30 | Euro Iseki Ltd | Valve control system |
| WO1989007293A1 (en) * | 1988-02-04 | 1989-08-10 | Cowells International Limited | Liquid level control system |
| EP0341595A1 (en) * | 1988-05-10 | 1989-11-15 | Harald Michael | Control device for a vacuum-actuated suction valve on a vacuum conduit, especially for sewage |
| US5292104A (en) * | 1991-11-27 | 1994-03-08 | Ebara Corporation | Vacuum interface valve |
| EP0550980A1 (en) * | 1992-01-07 | 1993-07-14 | Inax Corporation | Vacuum valve for a sewage collection system |
| US5280872A (en) * | 1992-01-07 | 1994-01-25 | Inax Corporation | Vacuum valve for a sewage collection system |
| EP0579815A1 (en) * | 1992-01-31 | 1994-01-26 | Burton Mech Contractors | Package system for collection-transport of waste liquids. |
| EP0579815A4 (en) * | 1992-01-31 | 1994-06-15 | Burton Mech Contractors | Package system for collection-transport of waste liquids |
| US5429068A (en) * | 1992-10-20 | 1995-07-04 | Fujitsu Limited | Deposition method for compound semiconductor forming device |
| EP0602604A1 (en) * | 1992-12-14 | 1994-06-22 | Ebara Corporation | Vacuum Valve |
| US5615701A (en) * | 1993-06-07 | 1997-04-01 | Sekisui Kagaku Kogyo Kabushiki Kaisha | Vacuum valve control device and vacuum valve |
| US5918853A (en) * | 1993-06-07 | 1999-07-06 | Seikisui Kagaku Kogyo Kabushiki Kaisha | Vacuum valve control device and vacuum valve |
| US5588458A (en) * | 1994-04-19 | 1996-12-31 | Ebara Corporation | Vacuum valve controller for vacuum sewer system |
| EP0826838A2 (en) * | 1996-08-26 | 1998-03-04 | Ebara Corporation | Vacuum valve controller |
| EP0826838A3 (en) * | 1996-08-26 | 1998-03-11 | Ebara Corporation | Vacuum valve controller |
| US5871027A (en) * | 1996-08-26 | 1999-02-16 | Ebara Corporation | Vacuum valve controller |
| EP1840282A3 (en) * | 2006-03-31 | 2012-12-05 | Evac International Oy | Vacuum sewer system |
| EP1840282A2 (en) | 2006-03-31 | 2007-10-03 | Evac International Oy | Vacuum sewer system |
| KR101381040B1 (en) | 2006-03-31 | 2014-04-04 | 에박 오이 | Vacuum sewer system |
| NO339995B1 (en) * | 2006-03-31 | 2017-02-27 | Evac Oy | Sewage system with vacuum |
| EP2415938A1 (en) * | 2009-04-03 | 2012-02-08 | Torishima Pump Mfg. Co., Ltd. | Control device for vacuum valve |
| EP2415938A4 (en) * | 2009-04-03 | 2014-03-19 | Torishima Pump Mfg Co Ltd | Control device for vacuum valve |
| US8875730B2 (en) | 2009-04-03 | 2014-11-04 | Torishima Pump Mfg. Co., Ltd. | Control apparatus of vacuum valve |
| WO2011066603A1 (en) * | 2009-12-03 | 2011-06-09 | Applidyne Australia Pty Ltd | Fluid control device and system |
| DE102014100797A1 (en) | 2014-01-24 | 2015-07-30 | Bilfinger Water Technologies Gmbh | Arrangement for sucking off liquid |
| DE102014100797B4 (en) | 2014-01-24 | 2018-08-02 | Bilfinger Water Technologies Gmbh | Arrangement for sucking off liquid |
| CN108980446A (en) * | 2018-08-31 | 2018-12-11 | 杭州电子科技大学 | A kind of lead button press switching device |
| CN108980446B (en) * | 2018-08-31 | 2020-03-17 | 杭州电子科技大学 | Lead wire button pressure switching device |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2149534B (en) | 1986-12-10 |
| GB8329780D0 (en) | 1983-12-14 |
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| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| PE20 | Patent expired after termination of 20 years |
Effective date: 20031107 |