CA1073317A - Control system for suction valve of vacuum dehydration installation - Google Patents
Control system for suction valve of vacuum dehydration installationInfo
- Publication number
- CA1073317A CA1073317A CA275,455A CA275455A CA1073317A CA 1073317 A CA1073317 A CA 1073317A CA 275455 A CA275455 A CA 275455A CA 1073317 A CA1073317 A CA 1073317A
- Authority
- CA
- Canada
- Prior art keywords
- suction valve
- valve
- sewage
- line
- control system
- 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.)
- Expired
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Abstract
CONTROL SYSTEM FOR SUCTION VALVE
OF VACUUM DEHYDRATION INSTALLATION
ABSTRACT OF THE DISCLOSURE
A control system for the suction valve of a vacuum dehydration installation is provided which causes the valve to open when the incoming sewage in an associated sewage system reaches a pre-determined level and which closes after the suction valve causes the drawing off by suction of a selected quantity of water and a further quantity of air following the water. The control system controls the opening and closing of the suction valve responsive to an air cushion located in a riser which is, for example, connected to the gravity line of a building or the like the gravity line serving as a collecting tank for sewage. This arrangement prevents corrosion and other problems associated with conventional actuators.
OF VACUUM DEHYDRATION INSTALLATION
ABSTRACT OF THE DISCLOSURE
A control system for the suction valve of a vacuum dehydration installation is provided which causes the valve to open when the incoming sewage in an associated sewage system reaches a pre-determined level and which closes after the suction valve causes the drawing off by suction of a selected quantity of water and a further quantity of air following the water. The control system controls the opening and closing of the suction valve responsive to an air cushion located in a riser which is, for example, connected to the gravity line of a building or the like the gravity line serving as a collecting tank for sewage. This arrangement prevents corrosion and other problems associated with conventional actuators.
Description
1~73317 :
Field of the Invention The present invention relates to a control arrangement for the suction valve of a vacuum dehydration installation for a sewage system, which valve opens automatically when the incoming sewage reaches a predetermined level and which then closes after withdrawing, by suction, a predetermined quantity of water as well as a quantity of air following the water.
Background of the Invention In systems of the type under discussion here, control functions, such as, for example, the control of a discharge valve~ are conventionally 10 carried out through the use of a float or other sensor as the detecting or sensing element. However, sewage in general, and household sewage in particu-lar, contains active constituents which attack and eventually corrode the float or sensor. Moreover, other constituents of such sewage tend to produce deposits or encrustations on the float or sensor which build up with time and can eventually prevent the associated device from operating as intended.
An example of a system which is similar in purpose to the system of the invention is disclosed in German Patent OS 2,117,353.
; Summary of the Inventi~n ~, , According to the present invention there is provided in a control 20 system for the suction valve of a vacuum dehydration installation which opensautomatically when the incoming sewage in a sewage system reaches a predeter-mined level and which closes after the valve draws off a predetermined quantity of water and a further quantity of air following the drawing off of the water, the volume of said quantity of air being two to fifteen times the volume of the quantity of water, wherein the improvement comprises means for controlling the opening and closing of the suction valve responsive to a continually main-tained air cushion located above a volume of fluid within a rising pipe section in communication with the sewage system containing the incoming sewage, said rising pipe section being emptied of fluid each time said suction valve is 30 opened so that said air cushion can be re-established by said further quantity of air. With this arrangement, only the suction valve itself comes into contact with the sewage and the suction valve is protected from .. , :. .. . . . .
10733~1.7 plugging up and deposit build-up because the valve is constantly cleaned by the liquid and air which is sucked therethrough at very high speeds.
It is noted that if the air cushion referr~d to is used to directly actuate the operating mechanism oE the suc-tion valve, the suction valve would be opened and closed very slowly. ~ore-over, as a result, the danger would exist of the suction valve being jammed or plugged by some of the larger constituents of the sewage. To prevent this, provision is made, in accordance with a preferred embodiment of the invention, to provide rapid actuation of the suction valve using the negative pressure of the vacuum line to whlch the suction valve i5 connected. To this end, a control valve is provided which is actuated responsive to the air cushion referred to and which controls actuation of the suction valve.
~ dvantageously, the control valve is part of a con-trol system which urther includes a bypass line for bypassing the control valve, a movable switching unit, an amplifier valve connected in the bypass line and operated by the switching unit, and a vacuum control line connected to the suction valve and including a branch connection which connects the vacuum line to the switching unit when the control valve is opened. The control system urther includes an additional control valve, operated responsive to the movement of the switching unit to an end posltion thereof, for opening the connection between the switching unit and the vacuum line, and for connecting to atmosphere an inlet line which com-municates with a throttling device in the form of a nozzle.
Other features and advantages of the invention will be set forth in, or apparent from, a detailed description of a preferred embodiment found hereinbelow.
Brief Description of the Drawings The single figure in the drawings is a schematic representation of the control system of the present inven-tion.
Description of the Preferred Embodiment ~ eferring to the drawings, a simplified representation of a vacuum line is shown at 10. A sucti~ valve 12 is disposed between vacuum line 10 and a conventional gravity line 14, the latter being subject to atmospheric pressure and being connected, for example, to a deaerated discharge pipe of a house or similar building. The construction of suction valve 12 is, for example, similar to that described in German Patent No. 1,609,245.
Vacuum pipe 10, a portion of which is shown, is connected to collecting tank (not shown) attached to a vacuum pump (not shown) into which sewage is drawn by suction. When the collecting tank is filled to a predetermined level, the collected liquid is pumped out of the tank and fed to a sewage plant tnot shown).
The suction valve 12 is normally closed and is opened onl~ for a short time in order to draw off the water which collects at the lower end of the gravity line 14.
; Before discussing the control system itself, it should be noted that the adjusting drive, and automatic triggering control, for the suction valve 12 preferably employ the negative pressure available in the vacuum plpe 10 so that there is no need for an additional power source. Further, no special tank is required at the lower end of the gravity line 14 in order to collect the house-hold sewage between the time intervals during which the suction valve 12 is opened since the gravity line 14 itself serves as a collecting tank. However, the amount of sewage collected should be controlled so that too much sewage is not collected by line 14, so that, first, putrefaction is prevented and, second, only relativel-small quantities of water are fed into the vacuum line under all conditions.
The basic in-tegers of the control arrangement for the suction valve 12 are illustrated in the drawings and are installed together in a control box (not shown). The connectlons to the control :, ~0~3317 ~ ~
arrangement comprise ~he gravity line 14, a control line 18 connected to the suction valve 12 and a vacuum control line 20 connected to the vacuum pipe 10.
The vacuum line 20 is connected through a permanently open connection 22 to a vacuum control line 24. Vacuum control line 24 is, in turn, connected to a first control valve 26, in the form of a diaphragm valve, which normally remains closed despite being continuously subjected to the negative pressure in the vacuum control lines 20 and 24. The control valve 26 will open only when the air cushion enclosed in the riser 16 has been compressed a sufficient amount responsive to the rising level of the sewage in the gravity line 14, such that the pressure exerted on the diaphragm of valve 26 causes opening of the valve. Under these circumstances) a connection is established between the vacuum control line 24 and a by-pass line 28 which is also connected to the control valve 26, By-pass line 28 is connected to a further by-pass line 30 which communicates with a second control valve 32.
Control valve 32 is connected through a supply line 34 to an auxil-iary switching unit 36 and, under initial conditions, the line 34 communicates the vacuum to an auxiliary switching unit 36. Unit 36 includes a vertically movable piston 38 and with a vacuum supplied thereto the vacuum-operated piston 38 will be drawn upwardly against the force of a return spring ~not shown) which is part of unit 36. In the upper end position of piston 38, a projection 40 on piston 38 engages and operates an amplifier valve 42 which is disposed in the path of movement thereof. Amplifier valve controls the opening and closing of a flow passage, which is normally closed, and which, when opened, provides communication between the by-pass line 28 and the vacuum control line 20. Thus, when valve 42 is operatedJ a by-pass is produced which bypasses the first control valve 26. Under ~hese circumstances, the by-pass line 30 and the second control valve 32 will be subjected to the full vacuum of ~ 5 -:
~733~7 of the vacuum line 10 as supplied by the by-pass line 28. The control valve 32 includes a spring and a snap-action mechanism (not shown) which provides for automatically interrupting the connection between the by-pass line 30 and supply line 34 res-ponsive to valve 32 being subject -to full vacuum. When so ac-tuated, valve 32 provides for the connection of line 34 to the outside atmosphere, i~e-, provides exhausting of line 34 to ambient.
It is important to the operation of the system described above that the air flowing into the llne 34 does not flow in sudden bursts, but is rather throttled, by means of a nozzle 44, before entry into the cylinder of the switching unit 36. By suitable selection of the nozzle opening, and thus of the throttling action provided, the time may be adjusted during which the piston 38 is pushed back into the lower end position thereof by the return spring referred to above. In addition, the piston 38 of switching unit 36 includes a projection 40 which is affixed thereto for movement therewith. An operating lever 46 of a further control valve 48 is disposed in the path of movement of projection 40.
The rate of descent of the piston 38, as determined by the throttling provided, determines the period of time within which the pro-jection 40 operates the lever 46 of the further control valve 48.
The lever 46 is mounted such that the projection 40 will operate the control valve 48 only during the descending movement of piston 38 but not during the upward movement thereof. During the time which projection 40 engages lever 46, during the descending movement of piston 38, the connection provided in control valve 48 between the vacuum control line 20 and the control line 18 to the suction valve 12 is open. ~s a result, suction valve 12 is open during this period. It will be evident that the rate of descent of piston 38, the force of the return spring referred to, the throttle effect of the nozzle 44 and the specific gravi-ty of the pis-ton 38, will be "
~733~7 determinative of the opening time of the suction valve 12.
Moreover, it is a simple matter -to adjust the opening of the suction valve 12 by a suitable selection of the nozzle 44 and of the return spring so that for each opening operation, the quantity of liquid present in the gravity line 1~ together with the additional quantity of air subsequently sucked into the vacuum line 10 will be such that the volume o~ air will amount to twice to fifteen times the quantity of liquid sucked in responsive to the pressure conditions of the vacuum line 10.
Piston 38 of the switching unit 36, at the end of the de-scending movement thereofl returns the control valve 32 back into its starting position. Since, at this time, projection 40 no longer operates amplifier valve 42 or control valve ~8, and be-cause liquid has been drawn from the gravity line 1~ and thus the pressure within the riser 16 has decreased, the control valve 26 will be switched back into the starting position thereof, and the entire system is returned to initial conditions.
Although the invention has been described relative to an exemplary embodiment thereof, it will be understood that other variations and modifications can be effected in this embodiment without departing from the scope and spirit o~ the invention.
Field of the Invention The present invention relates to a control arrangement for the suction valve of a vacuum dehydration installation for a sewage system, which valve opens automatically when the incoming sewage reaches a predetermined level and which then closes after withdrawing, by suction, a predetermined quantity of water as well as a quantity of air following the water.
Background of the Invention In systems of the type under discussion here, control functions, such as, for example, the control of a discharge valve~ are conventionally 10 carried out through the use of a float or other sensor as the detecting or sensing element. However, sewage in general, and household sewage in particu-lar, contains active constituents which attack and eventually corrode the float or sensor. Moreover, other constituents of such sewage tend to produce deposits or encrustations on the float or sensor which build up with time and can eventually prevent the associated device from operating as intended.
An example of a system which is similar in purpose to the system of the invention is disclosed in German Patent OS 2,117,353.
; Summary of the Inventi~n ~, , According to the present invention there is provided in a control 20 system for the suction valve of a vacuum dehydration installation which opensautomatically when the incoming sewage in a sewage system reaches a predeter-mined level and which closes after the valve draws off a predetermined quantity of water and a further quantity of air following the drawing off of the water, the volume of said quantity of air being two to fifteen times the volume of the quantity of water, wherein the improvement comprises means for controlling the opening and closing of the suction valve responsive to a continually main-tained air cushion located above a volume of fluid within a rising pipe section in communication with the sewage system containing the incoming sewage, said rising pipe section being emptied of fluid each time said suction valve is 30 opened so that said air cushion can be re-established by said further quantity of air. With this arrangement, only the suction valve itself comes into contact with the sewage and the suction valve is protected from .. , :. .. . . . .
10733~1.7 plugging up and deposit build-up because the valve is constantly cleaned by the liquid and air which is sucked therethrough at very high speeds.
It is noted that if the air cushion referr~d to is used to directly actuate the operating mechanism oE the suc-tion valve, the suction valve would be opened and closed very slowly. ~ore-over, as a result, the danger would exist of the suction valve being jammed or plugged by some of the larger constituents of the sewage. To prevent this, provision is made, in accordance with a preferred embodiment of the invention, to provide rapid actuation of the suction valve using the negative pressure of the vacuum line to whlch the suction valve i5 connected. To this end, a control valve is provided which is actuated responsive to the air cushion referred to and which controls actuation of the suction valve.
~ dvantageously, the control valve is part of a con-trol system which urther includes a bypass line for bypassing the control valve, a movable switching unit, an amplifier valve connected in the bypass line and operated by the switching unit, and a vacuum control line connected to the suction valve and including a branch connection which connects the vacuum line to the switching unit when the control valve is opened. The control system urther includes an additional control valve, operated responsive to the movement of the switching unit to an end posltion thereof, for opening the connection between the switching unit and the vacuum line, and for connecting to atmosphere an inlet line which com-municates with a throttling device in the form of a nozzle.
Other features and advantages of the invention will be set forth in, or apparent from, a detailed description of a preferred embodiment found hereinbelow.
Brief Description of the Drawings The single figure in the drawings is a schematic representation of the control system of the present inven-tion.
Description of the Preferred Embodiment ~ eferring to the drawings, a simplified representation of a vacuum line is shown at 10. A sucti~ valve 12 is disposed between vacuum line 10 and a conventional gravity line 14, the latter being subject to atmospheric pressure and being connected, for example, to a deaerated discharge pipe of a house or similar building. The construction of suction valve 12 is, for example, similar to that described in German Patent No. 1,609,245.
Vacuum pipe 10, a portion of which is shown, is connected to collecting tank (not shown) attached to a vacuum pump (not shown) into which sewage is drawn by suction. When the collecting tank is filled to a predetermined level, the collected liquid is pumped out of the tank and fed to a sewage plant tnot shown).
The suction valve 12 is normally closed and is opened onl~ for a short time in order to draw off the water which collects at the lower end of the gravity line 14.
; Before discussing the control system itself, it should be noted that the adjusting drive, and automatic triggering control, for the suction valve 12 preferably employ the negative pressure available in the vacuum plpe 10 so that there is no need for an additional power source. Further, no special tank is required at the lower end of the gravity line 14 in order to collect the house-hold sewage between the time intervals during which the suction valve 12 is opened since the gravity line 14 itself serves as a collecting tank. However, the amount of sewage collected should be controlled so that too much sewage is not collected by line 14, so that, first, putrefaction is prevented and, second, only relativel-small quantities of water are fed into the vacuum line under all conditions.
The basic in-tegers of the control arrangement for the suction valve 12 are illustrated in the drawings and are installed together in a control box (not shown). The connectlons to the control :, ~0~3317 ~ ~
arrangement comprise ~he gravity line 14, a control line 18 connected to the suction valve 12 and a vacuum control line 20 connected to the vacuum pipe 10.
The vacuum line 20 is connected through a permanently open connection 22 to a vacuum control line 24. Vacuum control line 24 is, in turn, connected to a first control valve 26, in the form of a diaphragm valve, which normally remains closed despite being continuously subjected to the negative pressure in the vacuum control lines 20 and 24. The control valve 26 will open only when the air cushion enclosed in the riser 16 has been compressed a sufficient amount responsive to the rising level of the sewage in the gravity line 14, such that the pressure exerted on the diaphragm of valve 26 causes opening of the valve. Under these circumstances) a connection is established between the vacuum control line 24 and a by-pass line 28 which is also connected to the control valve 26, By-pass line 28 is connected to a further by-pass line 30 which communicates with a second control valve 32.
Control valve 32 is connected through a supply line 34 to an auxil-iary switching unit 36 and, under initial conditions, the line 34 communicates the vacuum to an auxiliary switching unit 36. Unit 36 includes a vertically movable piston 38 and with a vacuum supplied thereto the vacuum-operated piston 38 will be drawn upwardly against the force of a return spring ~not shown) which is part of unit 36. In the upper end position of piston 38, a projection 40 on piston 38 engages and operates an amplifier valve 42 which is disposed in the path of movement thereof. Amplifier valve controls the opening and closing of a flow passage, which is normally closed, and which, when opened, provides communication between the by-pass line 28 and the vacuum control line 20. Thus, when valve 42 is operatedJ a by-pass is produced which bypasses the first control valve 26. Under ~hese circumstances, the by-pass line 30 and the second control valve 32 will be subjected to the full vacuum of ~ 5 -:
~733~7 of the vacuum line 10 as supplied by the by-pass line 28. The control valve 32 includes a spring and a snap-action mechanism (not shown) which provides for automatically interrupting the connection between the by-pass line 30 and supply line 34 res-ponsive to valve 32 being subject -to full vacuum. When so ac-tuated, valve 32 provides for the connection of line 34 to the outside atmosphere, i~e-, provides exhausting of line 34 to ambient.
It is important to the operation of the system described above that the air flowing into the llne 34 does not flow in sudden bursts, but is rather throttled, by means of a nozzle 44, before entry into the cylinder of the switching unit 36. By suitable selection of the nozzle opening, and thus of the throttling action provided, the time may be adjusted during which the piston 38 is pushed back into the lower end position thereof by the return spring referred to above. In addition, the piston 38 of switching unit 36 includes a projection 40 which is affixed thereto for movement therewith. An operating lever 46 of a further control valve 48 is disposed in the path of movement of projection 40.
The rate of descent of the piston 38, as determined by the throttling provided, determines the period of time within which the pro-jection 40 operates the lever 46 of the further control valve 48.
The lever 46 is mounted such that the projection 40 will operate the control valve 48 only during the descending movement of piston 38 but not during the upward movement thereof. During the time which projection 40 engages lever 46, during the descending movement of piston 38, the connection provided in control valve 48 between the vacuum control line 20 and the control line 18 to the suction valve 12 is open. ~s a result, suction valve 12 is open during this period. It will be evident that the rate of descent of piston 38, the force of the return spring referred to, the throttle effect of the nozzle 44 and the specific gravi-ty of the pis-ton 38, will be "
~733~7 determinative of the opening time of the suction valve 12.
Moreover, it is a simple matter -to adjust the opening of the suction valve 12 by a suitable selection of the nozzle 44 and of the return spring so that for each opening operation, the quantity of liquid present in the gravity line 1~ together with the additional quantity of air subsequently sucked into the vacuum line 10 will be such that the volume o~ air will amount to twice to fifteen times the quantity of liquid sucked in responsive to the pressure conditions of the vacuum line 10.
Piston 38 of the switching unit 36, at the end of the de-scending movement thereofl returns the control valve 32 back into its starting position. Since, at this time, projection 40 no longer operates amplifier valve 42 or control valve ~8, and be-cause liquid has been drawn from the gravity line 1~ and thus the pressure within the riser 16 has decreased, the control valve 26 will be switched back into the starting position thereof, and the entire system is returned to initial conditions.
Although the invention has been described relative to an exemplary embodiment thereof, it will be understood that other variations and modifications can be effected in this embodiment without departing from the scope and spirit o~ the invention.
Claims
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a control system for the suction valve of a vacuum dehydration installation which opens automatically when the incoming sewage in a sewage system reaches a predetermined level and which closes after the valve draws off a predetermined quantity of water and a further quantity of air following the drawing off of the water, the volume of said quantity of air being two to fifteen times the volume of the quantity of water, wherein the improvement comprises means for controlling the opening and closing of the suction valve responsive to a continually maintained air cushion located above a volume of fluid within a rising pipe section in communication with the sewage system containing the incoming sewage, said rising pipe section being emptied of fluid each time said suction valve is opened so that said air cushion can be re-established by said further quantity of air.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA275,455A CA1073317A (en) | 1977-04-04 | 1977-04-04 | Control system for suction valve of vacuum dehydration installation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA275,455A CA1073317A (en) | 1977-04-04 | 1977-04-04 | Control system for suction valve of vacuum dehydration installation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1073317A true CA1073317A (en) | 1980-03-11 |
Family
ID=4108317
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA275,455A Expired CA1073317A (en) | 1977-04-04 | 1977-04-04 | Control system for suction valve of vacuum dehydration installation |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1073317A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4791949A (en) * | 1986-08-29 | 1988-12-20 | Oy Wartsila Ab | Method of discharging sewage by vacuum and control apparatus for carrying the method into effect |
-
1977
- 1977-04-04 CA CA275,455A patent/CA1073317A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4791949A (en) * | 1986-08-29 | 1988-12-20 | Oy Wartsila Ab | Method of discharging sewage by vacuum and control apparatus for carrying the method into effect |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |