GB2452693A

GB2452693A - Water Flow Control

Info

Publication number: GB2452693A
Application number: GB0713357A
Authority: GB
Inventors: Ian David Taylor; Stuart Savill
Original assignee: AQUATRONIC GROUP MAN PLC
Current assignee: AQUATRONIC GROUP MAN PLC
Priority date: 2007-07-10
Filing date: 2007-07-10
Publication date: 2009-03-18
Anticipated expiration: 2027-07-10
Also published as: GB0713357D0; GB2452693B

Abstract

Water flow control apparatus has a water passage 10 provided with first and second two-way electrically operated valves 11, 12 (3/2 solenoid valve) each having a common port connected to the passage 10. The first valve has a first branch port 15 for connection to a vent and a second branch port 17 for connection to a water source, the normal setting of the first valve having the common port connected to the first branch port (vent). The second valve has a first branch port 16 for connection to a drain and a second branch port 18 for connection to a water consuming system, such as a wet radiator system, the normal setting of the second valve is to have the common port connected to the first branch port (drain). A control system for the valves is arranged to drive both valves from their normal settings when water is to be supplied to the water consuming system. Additionally a check valve 20, preferably a double check valve, is disposed between the supply passage and water consuming system. A pressure sensor may also be used to determine demand for water. An inspection section such as a transparent pipe section may be included.

Description

WATER FLOW CONTROL

This invention relates to water flow control apparatus. The invention further relates to a water-consuming system in combination with such water flow control apparatus, to control the delivery of water to the system.

Water supply regulations and bye-laws require provisions to be made to prevent the backflow of water from a water-consuming system to a water main supply pipe. For many systems, this is achieved by way of a break tank to which water is fed from the water main supply pipe, under the control of an automatic valve such as a ball valve, water being drawn from the break tank as required to the consuming system. The disadvantage of this is that the pressure of the water main supply cannot be utilised for supplying the water to the consuming system and if a pressure greater than that available from the head of water in the tank is required, it is necessary to employ an auxiliary pump.

There have been other proposals for preventing backflow into a water main supply pipe while still permitting the use of the pressure available in the supply pipe. Once such proposal is to be found in GB2299690; this requires the use of several different types of valve including an automatic air vent and anti-vacuum device. The long-term reliability of such an automatic air vent and anti-vacuum device may be less certain than with a power-operated valve.

It is a principal aim of the present invention to provide water flow control apparatus which is relatively cheap to construct, in that it uses a pair of conventional two-way power-operated valves operable to ensure there will be no backf low caused by back pressure or siphonage from the water-consuming system to a water main supply pipe, either during filling of the water-consuming system or when there is no demand for water from that water-consuming system.

According to this invention, there is provided water flow control apparatus comprising: -a water passage; -a first two-way electrically-operated valve having a common port connected to said passage, a first branch port arranged for connection to a vent and a second branch port arranged for connection to a water source, the first electrically-operated valve having a normal setting where the common port is connected to the first branch port; -a second two-way electrically-operated valve having a common port connected to said passage, a first branch port arranged for connection to a drain and a second branch port arranged for connection to a water-consuming system to which water is to be supplied, the second electrically-operated valve having a normal setting where the common port is connected to the first branch port; and -a control system for the first and second electrically-operated valves and arranged to drive both valves from their normal settings to their second settings when water is to be supplied to the water-consuming system.

Two-way electrically operated valves are well known and are widely available, for use with water. Such valves are usually referred to as 3/2 valves and though they may be motor-driven, most commonly take the form of solenoid valves. Such a valve has a normal setting where a common port of the valve connects to one of the two branch ports and when the valve has been energised, the common port then connects to the other of the two branch ports.

A solenoid valve of this kind is relatively cheap and advantageously is employed in constructing water flow control apparatus of this invention.

When implementing the water flow control apparatus, the passage should be arranged to extend generally vertically, with the first electrically operated valve mounted at or towards the upper end of the passage and the second electrically operated valve mounted at or towards the lower end of the passage. In this way, the first valve will vent the passage to atmosphere when the valve is in its normal (non-energised) setting, and the water source will be disconnected from the passage. Further, the second valve when in its normal (non-energised) setting will connect the passage to a drain and also disconnect the water-consuming system from the passage. In this way, any water within the passage will be permitted to drain under gravity through the second valve, with air entering the upper end of the passage through the first valve.

Local bye-laws may still require the provision of a check valve, and possibly a double check valve, between the passage and the pipework of the water-consuming system. In this case, such a check valve may be provided between the second port of the second valve and a pipe leading to the water-consuming system.

Advantageously, the drain connected to the first branch port of the second electrically operated valve includes an air gap or perhaps a tundish, whereby water draining from the passage may be observed. An alternative would be to provide a window or a transparent section in the passage, such that any water contained within the passage may be observed, as well as the draining of that water after a period of supply of water to the water-consuming system. A test port with a valve may also be provided on the passage such that opening the valve will allow observation of the outflow of any water within the passage.

The control system for the first and second electrically operated valves may operate on an automatic basis. This may be achieved by having a pressure sensor associated with the water-consuming system such that when the water pressure within that system falls below a pre-set threshold, the control system serves to drive the first and second electrically operated valves to their second settings, thus allowing water to flow from the water source to the water-consuming system. Once the pressure has risen within that system to above the threshold, the valves may be returned to their normal setting, thus disconnecting the water-consuming system from the water source and also allowing water within the passage to drain away.

In the event that the water-consuming system requires a greater pressure of water than is obtainable from the incoming water main, it would be possible to fit a pump in association with the flow control apparatus of this invention. For example, such a pump may be driven by an electric motor and be positioned between the second branch port of the second two-way valve and the water consuming system itself.

According to a second aspect of this invention, there is provided a water-consuming system requiring intermittent delivery of water thereto, which system comprises pipework for containing water, a pressure sensor arranged to sense the pressure of water within the pipework, and water flow control apparatus of this invention as described above, wherein the first branch port of the first electrically-operated valve is connected to a vent pipe, the second branch port of the first electrically-operated valve is connected to a source of water under pressure, the first branch port of the second electrically-operated valve is connected to a drain pipe and the second branch port of the second electrically-operated valve is connected to the pipework of said system, and the pressure sensor is connected to the control system to drive the first and second electrically-operated valves to their second settings when pressure below a predetermined threshold is detected.

By way of example only, one specific embodiment of water flow control apparatus of this invention will now be described in detail, reference being made to the accompanying drawing which shows the apparatus in diagrammatic form.

Referring to the drawing, there is provided a tubular passage 10 arranged with its axis generally vertical, a first 3/2 solenoid valve 11 disposed at the upper end of the passage 10 and a second 3/2 solenoid valve 12 disposed at the lower end of the passage 10. Each solenoid valve has a common port which is in communication with the passage 10 and two branch ports a selected one of which is connected to the common port, depending upon the operation of the valve. Each valve is controlled by a respective solenoid 13,14 and is arranged so that when the solenoids are not energised, the common port of the first valve 11 connects through the first port of that valve 11 to a vent pipe 1 5 and the common port of the second valve 12 connects through the first port of that valve 12 to a drain pipe 16. When the solenoids are energised, the common port of the first valve 11 connects through the second port of that valve 11 to a water supply pipe 17 and the common port of the second valve 12 connects through the second port of that valve 12 to a pipe 18 leading to a water-consuming system (not shown).

Also shown diagrammatically in the drawing is a check valve 20 disposed between the second port of the second valve 12 and the pipe 18; this check valve may be entirely conventional in its construction, to prevent backf low from pipe 18 into the passage 10. If required, a double check valve may be employed for this purpose. Further, a port 21 provided with a manually operable valve 22 communicates with the interior of the passage 10, partway between valves 11 and 12. Opening the valve 22 of this port 21 will show whether water is contained within the passage, above the level of that port.

A controller (not shown) is arranged to control the simultaneous supply of electricity to the solenoid valves 11 and 12. That controller could include a manual switch so permitting operation of the two valves 11 and 12 when required. In the alternative, the controller may have a pressure sensitive switch associated with pipework of the water-consuming system, arranged so that when the detected pressure falls below a pre-set threshold, both valves 11 and 12 are energised to permit the supply of water from the supply pipe 17 (which typically will be a main water supply pipe) to the water-consuming system, through pipe 18.

Following a period of supply of water, the solenoid valves 11 and 12 are de-energised so disconnecting pipe 18 from the passage 10, and disconnecting the water supply pipe 17 from that passage. Further, the passage 10 is vented at its upper end and water is allowed to drain through pipe 16 so that the passage 10 empties. This may then be verified by opening the valve 22 associated with port 21. Should there be a power failure during the supply of water to the water-consuming system, both valves 11 and 12 will be released to their safe position and the passage 10 will be drained.

Further security against backflow may be obtained by providing a second pressure sensitive switch to monitor the pressure in the water supply pipe 17.

The controller may then inhibit operation of the valves 11 and 12 even if the pressure in the water-consuming system falls below the pre-set threshold, if the second switch does not detect that the pressure in the water supply pipe 17 is sufficiently high.

It will be appreciated that the apparatus is arranged to allow the use of existing water mains pressure or the output of a pressure booster set for delivering water to a water-consuming system such as a heating or cooling system, while providing adequate backf low protection.

Claims

1. Water flow control apparatus comprising: -a water passage; -a first two-way electrically-operated valve having a common port connected to said passage, a first branch port arranged for connection to a vent and a second branch port arranged for connection to a water source, the first electrically-operated valve having a normal setting where the common port is connected to the first branch port; -a second two-way electrically-operated valve having a common port connected to said passage, a first branch port arranged for connection to a drain and a second branch port arranged for connection to a water-consuming system to which water is to be supplied, the second electrically-operated valve having a normal setting where the common port is connected to the first branch port; and -a control system for the first and second electrically-operated valves and arranged to drive both valves from their normal settings to their second settings when water is to be supplied to the water-consuming system.

2. Water flow control apparatus as claimed in claim 1, wherein each of the first and second electrically-operated valves comprises a two-way solenoid valve.

3. Water flow control apparatus as claimed in claim 2, wherein each of the first and second electrically-operated valves has the respective first branch port connected to the associated common port when the valve is not energised.

4. Water flow control apparatus as claimed in any of the preceding claims, wherein the passage is arranged to extend generally vertically when installed for use, the first electrically-operated valve is mounted at or towards the upper end of the passage and second electrically-operated valve is mounted at or towards the lower end of the passage.

5. Water flow control apparatus as claimed in any of the preceding claims, wherein a check valve is disposed between the passage and the connection to the system, which check valve allows the flow of water from the passage to the system when the second electrically- operated valve is in the appropriate setting.

6. Water flow control apparatus as claimed in claim 5, wherein the check valve comprises a double check valve.

7. Water flow control apparatus as claimed in any of the preceding claims, wherein the first branch port of the second electrically-operated valve is connected to a tundish having an outlet connected to a drain.

8. Water flow control apparatus as claimed in any of the preceding claims, wherein the first branch port of the second electrically-operated valve is provided with an outlet pipe leading to a drain-pipe with a visible air-gap between the outlet pipe and the drain-pipe.

9. Water flow control apparatus as claimed in any of the preceding claims, wherein the control system includes a sensor for detecting demand for water by the water-consuming system.

10. Water flow control apparatus as claimed in claim 9, wherein said sensor comprises a pressure sensor. -10-

11. Water flow control apparatus as claimed in any of the preceding claims, wherein the water passage includes a window through which the interior of said passage can be observed.

12. Water flow control apparatus as claimed in any of claims 1 to 10, wherein the water passage comprises a transparent tube through which the interior of said passage can be observed.

13. Water flow control apparatus as claimed in any of the preceding claims, wherein there is provided a test port communicating with the interior of the water passage and which includes an openable valve.

14. Water flow control apparatus as claimed in any of the preceding claims, wherein a pump is arranged between the second branch port of the second two-way valve and the water consuming system itself.

15. Water flow control apparatus as claimed in claim 1 and substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawing.

16. A water system requiring intermittent delivery of water thereto, which system comprises pipework for containing water, a pressure sensor arranged to sense the pressure of water within the pipework, and water flow control apparatus as claimed in any of claims 1 to 15, wherein the first branch port of the first electrically-operated valve is connected to a vent pipe, the second branch port of the first electrically-operated valve is connected to a source of water under pressure, the first branch port of the second electrically-operated valve is connected to a drain pipe and the second branch port of the second electrically-operated valve is connected to the pipework of said system, and the -11 -pressure sensor is connected to the control system to drive the first and second electrically-operated valves to their second settings when pressure below a predetermined threshold is detected.