GB1603330A

GB1603330A - Fluid supply system including a priming tank

Info

Publication number: GB1603330A
Application number: GB16987/78A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-04-28
Filing date: 1978-04-28
Publication date: 1981-11-25

Description

(54) A FLUID SUPPLY SYSTEM INCLUDING A PRIMING TANK (71) I, COLIN McMASTER-CHRISTIE, a British subject, of 49 Thames Street, Sunbury-on-Thames, Middlesex, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in the following statement :- This invention relates to fluid supply systems including priming tanks for fluid pumps, in particular for centrifugal pumps, for example for water supply systems for use in water craft or in caravans.

Water tanks in boats and caravans are usually located below the level of the tap, an electrically driven pump being provided to develop the necessary water pressure at the tap. Centrifugal pumps are frequently used for this purpose.

However, a disadvantage of locating the water tank below the tap which it feeds is that the tank can be run dry, and air then enters the supply system. In the case of centrifugal pumps, refilling the tank does not enable the water flow to be re-started, unless the pump is below the water level in the tank and filling the tank also fills the pump.

According to the present invention there is provided a fluid supply system including a priming arrangement and comprising a fluid source, a first chamber located above the level of the fluid source and integral with a second chamber located above the first chamber, the first chamber having a fluid inlet and a fluid outlet below the level of the inlet, a single pump having a fluid inlet and a fluid outlet, the fluid outlet of the first chamber being connected to the fluid inlet of the single pump, a first conduit connecting the fluid outlet of the single pump to the second chamber, a second conduit extending from the upper end of the first chamber into the second chamber, said second conduit having a non-return valve at its upper end which only allows flow of air from the first chamber to the second chamber, the second chamber having an outlet at its upper end.

Fluid supply systems in accordance with the invention can be used to prime fluid pumps situated above a tank from which they draw a fluid such as water. They have been found of particular value with centrifugal pumps, for example as used in water systems on boats or in caravans.

The valve means is preferably actuated by gravity but it can be electrically operated.

If desired, priming tanks in accordance with the invention can have an integral pump, in particular a centrifugal pump.

A fluid supply system including a priming tank embodymg the invention will now be described, by way of example, with reference to the accompanying drawings, in which :- FIGURE 1 is a vertical section through a fluid supply system of the invention, and FIGURE 2 is a vertical section through a further fluid supply system of the invention having an integral pump.

Referring to Figure 1, the illustrated fluid supply system comprises a priming tank having a first or lower chamber 1 integral with a second or upper chamber 2. The lower chamber 1 has a water inlet 3 for water from a tank or reservoir, at an upper region thereof, and a water outlet 4 in a lower region thereof. The upper chamber 2 has a water inlet 5 in a lower region thereof, and a water outlet 6 in an upper region thereof.

A conduit 7 extends between an upper region of the lower chamber 1 and an upper region of the upper chamber 2, for allowing air to pass from the lower chamber 1 into the upper chamber 2. A non-return valve 8 serves to prevent air from passing in the reverse direction from the upper chamber 2 into the lower chamber 1.

A projection 9 from the top of the lower chamber 1 serves to guide any air in chamber 1 into conduit 7.

A centrifugal pump 10, which does not form a part of the invention, is connected so as to pump water from the outlet 4 of chamber 1 into inlet 5 of chamber 2.

Operation of the system illustrated in Figure 1 will now be described.

The inlet 3 to chamber 1 is connected to a water tank R with the maximum water level in the water tank below the inlet 3. The outlet 6 is connected to an outlet tap (not shown). Either the pipework between the water tank and the tap inclues a non-return valve to prevent water flowing back into the water tank when the pump is not functioning, or the tap is such as to energise the pump while the tap is open, for example using a switch-actuated tap as described in British Patent Specification No. 1 259 903.

When air enters the feed inlet 3 from the water tank, the pump 10 pumps water from the chamber 1 into chamber 2 until air in the chamber 1 enters the pump 10. The chamber 2 is then full of water. The pump 10 is then unable to pump more water through the outlet 6 from the upper chamber 2, and the flow of water from the tap ceases. The pump 10 is then de-energised, and water flows from the upper chamber 2 into the lower chamber 1, through the inlet 5, the pump 10 and the outlet 4, in the reverse direction to when the pump 10 is working.

The water tank is then filled, and the pump 10 is then energised, for example by opening the tap if opening the tap energises the pump. Water is then pumped from the lower container 1 into the upper container 2, and this serves to draw water from the tank through the inlet 3 into the lower container 1. If the volume of air introduced through inlet 3 is sufficiently small, water will then enter the inlet 3 and flow through the lower chamber 1 to the outlet 4, thereby feeding the pump 10 which can pump water into the upper chamber 2 into the outlet 6.

However, if the volume of air in the pipe from the tank to the lower chamber 1 is greater than the volume of the chamber 1, water will not be pumped through outlet 6.

It is then a simple matter to de-energise the pump 10 with the flow of water in the direction from the tap to the tank prevented, for example by closing the tap or using a oneway-valve, and to allow water to run back from the upper chamber 2 into the lower chamber 1. The water which has already been sucked into the pipe from the tank but has not yet reached the inlet 3 remains in the pipe, and the water flowing from the upper chamber 2 into the lower chamber 1 displaces air from the top of chamber 1 into the upper chamber 2 through the valve 8.

The pump 10 can then be re-energised to draw the water further up the pipe to the inlet 3, and if necessary the pump 10 can be energised and de-energised a number of times until water flows through the tap.

It will be appreciated that if water can be drawn from the tap on the first re-energising of the pump 10, air will remain trapped in the chamber I until the pump IU ts deenergised, since the lower pressure in chamber 1 compared with the chamber 2 with the pump 10 working serves to keep the valve 8 closed. However, as soon as the tap is closed and the pump 10 is deenergised, air will flow through the conduit 7 and be displaced by water flowing from the upper chamber 2 into the lower chamber 1 through the pump 10.

In order to start up a priming tank as shown in Figure 1, before it has been used, water is poured into the upper chamber 2 through a filler opening 11 closed by an airtight cap 12.

A further system embodying the invention is shown in Figure 2. Parts similar to those of the priming tank of Figure 1 are referred to by the same reference numerals.

The system of Figure 2 has a centrifugal pump 10'integral with the priming tank.

The valve 8'at the top end of the conduit 7 is arranged to be beneath the water level in the upper chamber 2 when the chamber 2 is full of water. The system of Figure 2 functions in an identical manner to the system of Figure 1.

Claims

WHAT I CLAIM IS :- 1. A fluid supply system including a priming arrangement and comprising a fluid source, a first chamber located above the level of the fluid source and integral with a second chamber located above the first chamber, the first chamber having a fluid inlet and a fluid outlet below the level of the inlet, a single pump having a fluid inlet and a fluid outlet, the fluid outlet of the first chamber being connected to the fluid inlet of the single pump, a first conduit connecting the fluid outlet of the single pump to the second chamber, a second conduit extending from the upper end of the first chamber into the second chamber, said second conduit having a non-return valve at its upper end which only allows flow of air from the first chamber to the second chamber, the second chamber having an outlet at its upper end.
2. A fluid supply system according to claim 1 in which said pump is integral with said tank.
3. A fluid supply system according to claim 1 wherein said pump is a centrifugal pump.
4. A fluid supply system according to claim 1 wherein the non-return valve is operated by gravity.
5. A fluid supply system according to claim 1 wherein the non-return valve is operated electrically.
6. A fluid supply system according to claim 1 and including filler means for intro ducing fluid to be pumped into said seccuu chamber before the tank is put into service.
7. A fluid supply system according to claim 4 wherein said second conduit extends from the top of said first chamber into an upper region of said second chamber.
8. A fluid supply system substantially as hereinbefore particularly described and as illustrated in the accompanying drawings.