GB2105411A - Siphon systems - Google Patents

Abstract

A siphon system 10 for conveying liquids under gravity has an inlet 11 and an outlet 12 connected by a flexible tube 13. Valve 20 in the inlet and valve 30 in the outlet are provided to close the siphon system for filing with liquid via valve 23 or 44. To maintain both the inlet and outlet immersed in liquid, the outlet has a generally U-shaped liquid seal 31 so that its opening is above the lowest level of the outlet and a valve 46 is provided to control the flow of liquid through the system according to the head of liquid at the inlet. <IMAGE>

Description

SPECIFICATION Siphon systems This invention concerns siphon systems for conveying liquids, such as water or sewage, under gravity from a reservoir or other source of liquid.

Conveyance of liquids from reservoirs or other sources of liquid is often achieved by means of pumping or by means of laying a pipeline or forming a tunnel along hydraulic gradient from the reservoir or liquid source to a suitable discharge point. Pumping is often noisy and smelly due to engine fumes and the running costs can be very high. Also, there are statutory limits on the amounts of noise and fumes in certain areas. Thus pumping can be an unsatisfactory method of conveying liquids. Laying a deep pipeline or forming a tunnel can also be very expensive.

In the case of pipelines, such as sewers, inspection and repair work has to be carried out from time to time and in order to divert the flow of liquid again pumping is used with its attendant disadvantages.

It is known that liquids can be conveyed under gravity using siphon systems and this invention seeks to provide a siphon system which may be used in place of the pumping or other methods mentioned above.

According to this invention there is provided a siphon system for conveying liquids from a reservoir or other liquid source comprising a tube or pipe having an inlet and an outlet both of which are closeable during filling of the siphon with liquid, means for maintaining the inlet immersed in liquid and the outlet being in the form of a liquid seal.

In order to maintain the inlet immersed in liquid, advantageously the flow of liquid through the siphon system from the reservoir or other source is controlled so that no more liquid can enter the inlet once a desired minimum level of liquid in the reservoir or other source is reached.

This may be achieved by a suitable valve, such as a float valve at or near the open end of the inlet or a pressure operated valve at some point in the siphon system. The pressure operated valve could be a reflux valve or a swing check valve having a valve member counter-balanced by a weight on a lever connected to the valve member. The lever could be graduated to permit positioning of the weight at an appropriate graduation to close the valve when the desired minimum level of liquid in the reservoir or other liquid source is reached.

The liquid seal at the outlet may be provided by having the outlet opening higher than the lowest point of the outlet pipe. This may advantageously be achieved by having the end of the outlet upturned so that liquid will always be retained in the outlet end. Means for emptying the outlet end may be provided, such as a suitable valve or a removable plug or stopper.

To fill the siphon system with liquid before siphoning can start suitable on/off valves may be provided at the inlet and outlet ends to close them and at upper parts of the system one or more valves may be provided which can,be connected to a liquid supply to be used for filling the siphon system. Because the inlet and outlet ends of the siphon system will often be inaccessible, it is preferred to provide the on/off valves with suitable linkages for remote operation thereof. In the case of flow control being by means of a float valve, the float valve itself can be used to close the inlet end. Advantageously the siphon systems of the invention will include one or more gas collection chambers so that, as the siphon system is filled, gases in the system can be collected and released via suitable valves.To permit release of collected gases during operation of the siphon, the release valves preferably have a liquid seal through which the gases pass. By the provision of a liquid seal, collected gases may be released automatically during operation of the siphon.

Conveniently, the release valves are the liquid supply valves themselves and the gas collection chambers are associated therewith.

In a preferred system, the inlet and outlet are formed of rigid piping which may be made up of connected sections of piping. Piping in sections will permit ready dismantling and replacement of sections and also permit lengthening or shortening of the inlet and outlet as required by addition, removal or replacement of sections.

Means for spacing the inlet end from the bottom of the reservoir or other liquid source may be provided such as a height adjustable stand.

The inlet and outlet pipes preferably are branched at their upper ends, one branch forming a gas collection chamber and having a liquid supply valve connected thereto and the other branch being connected to the corresponding branch of the other pipe by a flexible tube or pipe.

In use, the siphon system of the invention has its inlet end immersed in the reservoir or other source of liquid and its outlet end positioned at a discharge point which is lower than the minimum desired level of the reservoir or other liquid source.

The inlet and outlet ends are then closed and the siphon system filled with liquid, collected gas being released as necessary. The inlet and outlet can then be opened and liquid will begin to flow through the system under gravity until the desired minimum level of liquid in the reservoir or other liquid source is reached due to the flow control valve. The rate of flow of liquid through the siphon is also controlled by the flow control valve which will open or close in accordance with the level of liquid in the reservoir or the pressure of liquid in the system depending on what type of flow control valve is used.

When using the system to divert liquid from a pipeline, it will be appreciated that a reservoir of liquid will be formed in the pipeline by plugging of the pipeline just beyond the inlet of the siphon system.

This invention will now be further described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows schematically a pressure type valve controlled siphon system; Figure 2 shows an alternative inlet arrangement for the system of Figure 1; Figure 3 shows an alternative outlet arrangement for the system of Figure 1; Figure 4 shows schematically a float valve controlled siphon system; Figure 5 shows schematically a pressure valve controlled siphon system in use diverting liquid flow from a sewer; Figure 6 shows schematically variation on part of the system of Figure 5; Figure 7 shows schematically a float valve controlled siphon system in use maintaining a constant level in a reservoir; Figure 8 shows schematically a layout for conveying liquid over high ground; and Figure 9 shows schematically a variation on part of the layout of Figure 8.

Referring to Figures 1 to 3, a siphon system 10 has an inlet pipe 11 and outlet pipe 12 and a flexible tube 13 connecting them. The inlet pipe 11 has its lower end 14 immersed in the liquid to be conveyed and the outlet pipe has its lower end 1 5 disposed at the desired discharge point.

The inlet pipe 11 is made up of connected sections namely an inlet valve section 1 7 a tube 1 8 and a siphon filling section 1 9 in series. The length of the inlet pipe 11 can be extended or shortened by replacing the tube 18 with longer or shorter lengths of tube or by adding more tube sections.

The inlet valve section 1 7 is mounted on a height adjustable stand 16 to provide a clearance between the valve section 1 7 and the bottom of the reservoir. The inlet valve section 17 has therein a valve 20 controllable by linkage 21 so that the inlet can be closed when the siphon is being filled.

The filling section 19 is branched having a branch 24 connected to the flexible tube 13 and a branch 25 to a valve 23 through which the siphon can be filled. The branch 25 conveniently provides a gas collection chamber 26, the trapped gas being releasable through the valve 23.

The outlet pipe 12 is also made up of connected sections, namely an outlet valve section 30 a liquid seal 31, a tube 32, and a siphon filling section 33. The tube 32 may be lengthened or shortened in the same way as the inlet pipe 11.

The outlet valve section 30 comprises a branch 37 out of which a gate member 36 is movable by means of a bevel gear arrangement 38 turned by a handle 39 to close the valve section 30.

The liquid seal 31 is a U-shaped vessel having its outlet 40 directed upwardly. The vessel can be emptied by removal of a plug 42 from the vessel by pulling on cable 43 attached to the plug.

The filling section 33 is of similar construction to inlet filling section 1 9 having an on/off valve 44 and a gas collection chamber 45.

The flexible tube 13 includes in a generally horizontal section thereof a pressure operated valve 46, such as a swing check or reflux valve, which comprises a valve member 47 connected to a lever arm 48 on, which a weight 49 is slidable.

The lever arm 48 is graduated to indicate various differences of liquid level between the ends of the siphon system.

To operate the siphon, valves 20 and 30 are closed and the siphon filled with liquid through valve 23 and/or valve 44. Trapped air may be released through valve 44 and/or valve 23. When the siphon is completely filled, the valves 23 and 44 are closed. The weight on the lever arm of the pressure valve 46 is then set to a graduation position which indicates the difference in level between the surface of the liquid to be siphoned and the point of discharge. When the inlet of the siphon is immersed in the liquid to be siphoned valves 20 and 30 are opened to allow liquid to flow through the siphon under gravity. The pressure valve 46 will control the flow of liquid, since as the pressure of liquid on the valve member 47 increases or decreases due to a corresponding increase or decrease in the head of liquid to be siphoned, the valve member 47 will open or close respectively.The position of the weight on the lever arm will determine the pressure which will cause the valve member to open and allow the liquid to flow or to close and stop further flow of liquid.

In Figure 2 an alternative inlet arrangement comprises an elbow pipe section 52 having a gate type valve 53 near its open end and operable remotely by means of linkage 54. In Figure 3 an alternative outlet arrangement comprises a gate type valve 56 at the mid-point of a U-shaped liquid seal vessel 55. As in Figure 1 emptying of the vessel 55 is by removal of a plug 42 by means of cable 43.

Turning to Figure 4, siphon system 100 has an outlet pipe 102 which is the same as the outlet pipe 12 of Figure 1 and is numbered similarly, and an inlet pipe 101 connected by a flexible tube 103.

The inlet pipe 101 has its lower end upturned and has a float valve 104 in its upturned end. The float valve has its arm 105 connected to a cable 106 so that the valve can be held closed during filling of the siphon. At its upper end, the inlet pipe 101 is branched having at the end of one branch 107 an on/off valve 108 through which the siphon can be filled and the other branch 109 being connected to the flexible tube 1 03. The branch 107 also provides an air collection chamber 111.

A liquid supply vessel 110 connected to valve 108 provides a liquid seal through which air trapped in the air collection chamber 111 can escape.

Operation of siphon system 100 is similar to that of the system of Figure 1 in that the inlet and outlet valves are closed, the siphon filled and trapped air allowed to escape. When the inlet is immersed in liquid to be siphoned the inlet and outlet valves can be opened to allow liquid to flow through the siphon under gravity provided the outlet is lower than the inlet.

The float valve controls the amount of liquid passing through the siphon depending on the level of liquid in the reservoir. If the level is high the float valve opens further and if the level is low the float valve closes to reduce the flow of liquid or stop it completely.

The siphon system of Figure 1 is probably more suitable for use with contaminated water supplies such as sewage whereas the system of Figure 4 is probably more suitable for clean water supplies so that the float valve does not become obstructed.

Various applications of the siphon systems of Figures 1 and 4 are shown in Figures 5, 6 and 7. In Figure 5 a siphon system such as shown in Figure 1 is used to divert the flow of sewage from a gravity sewer so as to enable inspection, repair, replacement or some other work to be carried out on the sewer without interrupting the flow of sewage.

The inlet of the siphon is placed in the sewer 1 50 upstream of the section on which work is to be carried out and the outlet is placed in the sewer 1 50 downstream of that section. The sewer 1 50 is then blocked just after the siphon inlet with stopper or plug 151 to form a reservoir 152 of sewage. The siphon system is then filled with water, the pressure valve set appropriately and the siphon opened. The sewage will be conveyed from the reservoir 1 52 under gravity through the siphon to the discharge point 1 53.

If the flexible pipe 13 has to pass over high or undulating ground between the inlet 11 and outlet 12, it may be necessary to provide additional siphon filling/gas release valves at the highest ground points as shown in Figure 6. An inverted T-piece 160 is inserted in the pipe 13, the upwardly directed branch of which forms a gas collection chamber 161 and is connected to a valve 162 through which liquid can be supplied to the siphon or collected gas can be released.

In Figure 7 a float valve siphon system, such as that of Figure 4, is used to maintain a constant level of water in a reservoir 170 by discharging water into a ditch 1 71 or other convenient discharge point.

The inlet of the siphon system is placed in the reservoir 1 70 and the outlet in the ditch so that the outlet is at a lower level than the desired constant level of the reservoir. The siphon is filled with water and then opened to allow water to flow under gravity from the reservoir into the ditch. The length of the inlet is set so that the float valve will be closed when the desired constant level of the reservoir is reached. If the level of water in the reservoir rises the float valve will open to allow water to be siphoned off until the desired constant level is once again reached.

In Figure 8, a siphon system like that of Figure 1 is used for a permanent siphon installation to provide an alternative method of conveying water over high ground. Present methods would involved pumping or laying a pipeline on a hydraulic gradient necessitating deep excavations or tunnelling.

As shown, the inlet is in a pit or manhole 200 which receives an inflow of water and the outlet is in a lower pit 201 on the other side of a hill 202, i.e. on a hydraulic gradient as represented by line 205. The flexible pipeline 13 of the siphon system is laid underground but following the contour of the hill. At the top of the hill the pipeline has in a pit 206 the pressure valve 46, a filling valve 23 and a gas collection chamber 26.

The system operates as previously described by filling of the siphon and then opening the siphon to allow water to flow, the rate of flow being controlled by the pressure valve 46.

Figure 9 shows a variation on the Figure 8 layout in which automatic release of collected gases is possible. Thus the pipeline 13 includes not only a reflux valve and a filling valve 23 but also an automatic gas release valve 203 connected to a liquid reservoir 204.

It will be appreciated that siphon systems of the invention can be used in many circumstances where a liquid is to be transported down a hydraulic gradient without the need for pumping equipment or expensive excavation or tunnelling work.

Claims (17)

1. A siphon system for conveying liquids from a reservoir or source of liquid comprising a tube or pipe having an inlet and an outlet both of which are closeable during filling of the siphon with liquid, means for maintaining the inlet immersed in liquid and the outlet being in the form of a liquid seal.

2. A system as claimed in claim 1 wherein the means for maintaining the inlet immersed in liquid comprises a liquid flow control valve.

3. A system as claimed in claim 2 wherein the flow control valve is a float valve at or near the inlet end.

4. A system as claimed in claim 2 wherein the flow control valve is a pressure operated valve positioned in a generally horizontal section of the tubular pipe.

5. A system as claimed in any one of claims 1 to 4 wherein the outlet has its opening above the lowest point of the outlet to provide the liquid seal.

6. A system as claimed in claim 5 wherein the outlet has an upturned end.

7. A system as claimed in any one of claims 1 to 6 having at the inlet and the outlet end an on/off valve.

8. A system as claimed in claim 7 wherein the on/off valve at the inlet end is the float valve.

9. A system as claimed in any one of claims 1 to 8 having one or more liquid supply valves at high points of the siphon system.

10. A system as claimed in claim 9 including one or more gas collection chambers from which collected gas can be released via a valve.

11. A system as claimed in claim 10 wherein the or each gas release valves is or are connected to a liquid seal through which the collected gases are released.

12. A system as claimed in claims 10 or 11 wherein the gas release valves are the liquid supply valves.

13. A system as claimed in any one of claims 1 to 12 having means for releasing liquid from the liquid seal.

14. A system as claimed in claim 1 3 wherein said liquid release means is a valve or a removable plug.

1 5. A system as claimed in any one of claims 1 to 14 having means for spacing the inlet end from the bottom of the reservoir or liquid source.

1 6. A system as claimed in claim 1 5 wherein said spacing means is a height adjustable stand.

17. A system as claimed in any one of claims 1 to 1 6 wherein the inlet and outlet ends are connected by a flexible tube or pipe.

1 8. A system as claimed in claim 1 7 wherein the inlet and outlet ends are formed of rigid piping which may be dismantled for extending or shortening thereof or for transportation.

1 9. A siphon system substantially as hereinbefore described with reference to and as illustrated in any one of the accompanying drawings.