GB2248671A - Pump assembly - Google Patents

Abstract

A pump assembly for use in a shower installation has a main flow passageway with an inlet 20 connected to the shower outlet 101 of a bath mixer fitting 102 and an outlet 22 joined to the shower head 110 of the installation. An electrically-driven pump 14 draws water from the shower outlet and delivers it along the main passageway to the shower head. Operation of the pump is controlled by a flow sensitive switch 24. A flap 26 in the main passageway carries a magnet 30 which operates the switch 24. The rate of flow of water through the main passageway is controlled by a manually-operable flow control valve 40 across which is a by-pass flow through which is under the control of a valve 54 responsive to the water pressure in the by-pass. <IMAGE>

Description

PUMP ASSEMBLY This invention relates to a pump assembly for increasing the rate of flow of water to a shower head from a valve assembly where water temperature control can be effected.

It is common practice for a shower head to be supplied with low pressure cold and hot water via a mixer tap or valve assembly including a pair of taps where the ratio of hot to cold water can be manually adjusted to achieve the desired temperature of water emitted from the shower head. The low pressure is provided by arranging for the water to be supplied from a water tank installed at a high position in a domestic home, eg in the loft. The flow rate of water through the shower head depends inter alia upon the vertical distance between the shower head and the water storage tank. In many cases, the total flow of water which is achievable by such a low pressure supply is insufficient to obtain a satisfactory shower.

It is an object of the present invention to provide a convenient and satisfactory pump assembly for increasing the rate of flow of water to a shower head from a valve assembly where water temperature control can be effected.

According to the present invention, there is provided a pump assembly for increasing the rate of flow of water to a shower head from a valve assembly where water temperature control can be effected, said pump assembly comprising (1) a main passage having an inlet which is connected in use to the valve assembly and an outlet which is connected in use to the shower head, (2) an electrically driven pump operably disposed between said inlet and said outlet, (3) a manually operable flow control valve disposed in said main passage, (4) a water flow-sensitive electrical switch disposed in said main passage between said inlet and said flow control valve, said electrical switch being arranged to close an electrical supply circuit to the electrically driven pump so as to cause the pump to be energised when flow of water is sensed in the main passage, (5) a valve by-pass passage connected with said main passage upstream and downstream of said manually operable flow control valve, and (6) a pressure-sensitive valve disposed in said bypass passage and arranged to close said by-pass passage when the pressure difference across the pressuresensitive valve exceeds a predetermined value; wherein (a) the manually operable flow control valve is moveable between first and second limit positions corresponding to minimum and maximum restrictions to flow, respectively, (b) in said first limit position, the flow restriction provided by the manually operable flow control valve is greater than the flow restriction provided by the valve assembly when the latter is open whereby the pump cannot apply an excessive pressure difference across the open valve assembly, and (c) in its second limit position, the manually operable flow control valve is sufficiently open to permit a water flow rate above a predetermined amount when the valve assembly is open in use, so that the electrical switch maintains the electrical supply circuit closed.

Most preferably, the manually operable flow control valve and the water flow-sensitive electrical switch are both disposed downstream of the electrically driven pump.

The terms "upstream" and "downstream" are used herein in relation to the direction of flow of water through the pump assembly from the inlet to the outlet thereof.

The water flow-sensitive electrical switch preferably comprises a flap pivotally mounted in the main passage and movable when acted upon by flow of water therethrough from a first position in which it substantially obscures the main passage, into a second position in which it permits flow of water through the main passage, a magnet mounted on the flap, and a magnetically operable switch disposed externally of the main passage and adjacent said magnet so as to be acted upon by said magnet, whereby movement of the flap out of its first position by flow of water through the main passage causes the magnetically operable switch to change its switched state.Most preferably, the magnetically operable switch comprises first and second electrical contacts mounted for relative movement between an open position and a closed position, first and second ferromagnetic means associated with the first and second contacts respectively, a first magnet positioned adjacent said ferromagnetic means with one of its poles closer to the first ferromagnetic means than the other of its poles so as to induce a magnetic field in the first ferromagnetic means which, in turn, induces a magnetic field in the second ferromagnetic means thereby tending to close the contacts, and a second magnet constituted by the afore-mentioned magnet mounted on the flap, said second magnet being mounted for movement relative to the second ferromagnetic means so that, in one position of movement, the magnetic field induced in the second ferromagnetic means augments that induced by the first magnet thereby increasing the attractive force between the ferromagnetic means and maintaining the electrical contacts in the closed position, whilst in another position of the second magnet, the magnetic field induced in the second ferromagnetic means reverses the magnetic field induced therein by the first magnet, whereby a repulsion between the first and second ferromagnetic means causes the contacts to be moved into the open position.

One particular advantage of the pump assembly according to the present invention is that, by avoiding the application of an excessive pressure drop across the open valve assembly when the pump is operated, the risk of inadvertently drawing air into the water being passed to the shower head is substantially reduced. In this respect, it will be appreciated that the valve assembly which is normally fitted for a normal low pressure water supplied shower head is not designed to have a reduced pressure applied downstream thereof.Particularly in the case where the valve assembly comprises a mixer tap for supplying hot and cold water to a bath, and a manually operated knob or lever for diverting water to the shower head, there is a very real risk that, without the use of a pump assembly according to the present invention, air will be drawn into the water through the outlet or outlets which normally supply water to the bath since no precautions are made to ensure that the diverter is capable of providing an air tight seal between the bath outlet or outlets and the shower outlet.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawing which is a schematic rear view, partly in section, of a pump assembly according to the present invention.

Referring now to the drawing, the pump assembly comprises a composite body 10 formed partly by a first housing 12 and partly by a second housing 14. The second housing 14 houses a pump impeller (not shown) driven by an electric motor 16. Within the body 10 is defined a main passage 18 which passes through both the first and second housings 12 and 14 and which has an inlet 20 associated with the second housing 14 and an outlet 22 associated with the first housing 12.

The inlet 20 is designed to be connected via a rigid pipe or flexible hose 100 (only diagrammatically shown) with a shower outlet 101 on a conventional bath mixer tap assembly 102 (shown on a smaller scale) having an outlet 103 for discharging into a bath and a knob-operated diverter valve 104 for diverting water from the bath outlet 103 to the shower outlet 101. Such a tap assembly 102 has hot and cold water taps 105 and 106 respectively which can be manually adjusted to control the relative proportions of hot to cold water to enable the temperature of the water passed from respective inlets 107 and 108 to the bath outlet 103 or to the shower outlet 101 to be adjusted to suit the user.

Disposed within the part of the main passage 18 defined by the first housing 12 is a water flow-sensitive electrical switch indicated generally by arrow 24. Such switch 24 is of the type described hereinabove. Briefly, such switch comprises a flap 26 which is pivoted at 28 and which, in the position illustrated in the drawing, lies across the flow passage 18. At its lower, pivotremote end, the flap 26 carries a permanent magnet 30. A reed switch 32 is disposed externally of the housing 12 adjacent the magnet 30 so as to be acted upon by the latter when the flap 26 is in the position illustrated in the drawing. The switch 24 is also provided with a magnet 34 which is fixed relative to the reed switch 32 and acts to augment the action of the magnet 30.The arrangement of the reed switch 32 and magnets 30 and 34 is such that, in the position illustrated in the drawing, the reed switch 32 is maintained electrically open, whilst, when a flow of water above a predetermined level takes place through the passage 18, the flap 26 is moved in an anti-clockwise direction about pivot 28 so that the magnet 30 is moved away from the reed switch 32. This causes the latter to close. The reed switch 32 is associated with an electrical supply circuit to the motor 16 so that, when the reed switch 32 is closed, the motor 16 and thereby the pump is energised.

The pump assembly further comprises a flow control valve 40 which is disposed between the water flow-sensitive electrical switch 24 and the outlet 22. The valve 40 comprises a rotary valve member 42 having a passage 44 therethrough. In the position illustrated in the drawing, the passage 44 is in a fully open position corresponding to a first limit position of the valve 40. The rotary valve member 42 is operably connected with a manual control knob 46 disposed externally of the first housing 12. A stop 48 on the housing 12 engages in a recess 50 in the knob 46. Opposite ends of the recess 50 define, with the lug 48, limit positions of movement of the valve member 42. In the first limit position illustrated in the drawing, the lug 48 engages against one end of the recess 50.In the opposite position, the lug 48 engages against the other end of the recess 50, and this corresponds to a second limit position of the valve member 42. In the second limit position of the valve member 42, the passage 44 is scarcely exposed to the passage 18 with the result that there is a very high restriction to flow. In its second limit position, the passage 44 has a cross sectional size which is less than the cross sectional area available for flow through the valve assembly when the taps of the latter are opened to the usual extent.

The housing 12 also includes a by-pass passage 52 which by-passes the valve 40 and which includes a pressure sensitive ball valve 54. The ball valve 54 includes a frusto-conical seat facing in the upstream direction, a ball 58 engageable with the seat 56, and a compression spring 60 serving to urge the ball 58 away from the seat 56.

In use, the outlet 22 is connected with a shower head 110 (shown on a smaller scale) via a flexible hose 111, whilst the inlet 20 is connected with the mixer tap assembly 102, as aforesaid. A person wishing to use the shower first opens the taps 105 and 106 on the assembly to the required extent to set the desired temperature by feeling the temperature of the water issuing from the bath outlet 103, although this is optional. Then, he or she operates the diverter valve 104 to divert the water to the shower outlet 101 from where the mixture of hot and cold water is caused to flow through the hose 100 and into the inlet 20. At this stage, the valve 40 may be in its fully restricted position (ie second limit position) and the ball 58 will be in a position in which it is urged away from the seat 56 by spring 60.The hot and cold water mixture flows through the housing 12 and through the by-pass passage 52, as well as through the valve 40 to a limited extent. The flow of water causes the flap 26 to be pivoted in an anti-clockwise direction about pivot 28 sufficiently far for the reed switch 32 to be closed, thereby energising the pump 14. This substantially increases the pressure in the housing 12 and causes a sufficient pressure build-up in the by-pass passage 52 for the ball 58 to be urged against the seat 56 against the action of the spring 60, thereby preventing further flow of water through the by-pass passage 52. However, the flow rate through the valve 40, even when in its minimum flow position, is still such as to maintain the flap 26 sufficiently open for the pump 14 to continue running. The user operates the valve 40 by rotation of the knob 46 to obtain the desired flow rate.

At this stage, the user may also further adjust the taps 105 and 106 on the mixer tap assembly 102 to set or reset the water temperature.

At the end of the shower time, the user turns off the taps 105 and 106 on the mixer tap assembly 102. The diverter valve 104 may be of the type which automatically re-sets to a position in which it connects the inlets 107 and 108 with the bath outlet 103. If not, the user may choose to operate the valve 104 to divert water to the bath outlet 103 before turning off the taps 105 and 106.

In either case, when the flow of water through the hose 100 stops, the flap 26 is permitted to move back to the position where the reed switch 32 is opened. The pump 14 is de-energised and the ball 58 is moved off the seat 56 by the spring 60. It will be appreciated from the above that there is less risk of an excessively high pressure drop being exerted across the mixer tap assembly 102 so that there is a reduced risk of air being drawn into the system when the pump is operated.

Claims (14)

Claims.

1. A pump assembly comprising a main water flow passageway having an inlet and an outlet, an electrically-driven pump operatively connected between the inlet and the output, means sensitive to the flow of water through the main passageway for bringing the pump into operation when the flow rate through the main passageway exceeds a predetermined value and for de-activating the pump when the flow rate is below that value, and a manuallyoperable valve for controlling the rate of flow through the main passageway.

2. An assembly as claimed in claim 1 in which the flow sensitive means comprises a flap located within the main passageway and mounted for movement between a first position in which it substantially closes the main passageway and a second position in which the main passageway is open.

3. An assembly as claimed in claim 2 in which the flow sensitive means includes an electric switch operable to an open position by the flap when in its first position and to a closed position when the flap when in its second position.

4. An assembly as claimed in claim 2 or 3 in which the switch is magnetically-operable, and in which the flap carries a first magnet for operating the switch to its open position.

5. An assembly as claimed in claim 4 in which the switch is associated with a second magnet which is so arranged magnetically as to augment the action of the first magnet.

6. An assembly as claimed in any one of the preceding claims in which there is a by-pass connected to the main passageway both upstream and downstream of the manually-operable valve, and in which flow through the by-pass is controlled by a flow control valve means sensitive to the pressure difference across the flow control valve.

7. An assembly as claimed in claim 6 in which the flow control valve comprises resilient means that urge the flow control valve into a position in which the by-pass is open unless the pressure difference exceeds a preset value when the by-pass is closed.

8. An assembly as claimed in any one of the preceding claims in which the manually-operable valve is operable only between a first position in which the flow through the main passageway is a minimum and a second position in which that flow is a maximum.

9. An assembly as claimed in any one of the preceding claims in which the manually-operable valve is located downstream of the pump.

10. An assembly as claimed in claim 9 in which the flow sensitive means is located in the main passageway between the pump and the manually-operable valve.

11. A shower installation comprising a mixer fitting with a diverter valve operable to permit water to leave the fitting either via a bath outlet or via a shower outlet, and, connected to the shower outlet, a pump assembly as claimed in any one of the preceding claims.

12. An installation as claimed in claim 11 when appended to claim 8 in which the first position of the manually-operable valve is such that the water flow through the main passageway is limited to a value that prevents the pump creating an excessive pressure across the fitting.

13. A pump assembly substantially as herein described with reference to and as illustrated by the accompanying drawing.

14. A shower installation substantially as herein described with reference to and as illustrated by the accompanying drawing.