GB2359860A

GB2359860A - Reciprocating and rotating pump

Info

Publication number: GB2359860A
Application number: GB0103544A
Authority: GB
Inventors: Henri Gerhard Willem Pierson
Original assignee: ADPEC CANARIAS SL
Current assignee: ADPEC CANARIAS SL
Priority date: 2000-02-29
Filing date: 2001-02-13
Publication date: 2001-09-05
Also published as: GB0004838D0; GB0103544D0

Description

2359860 1 IMPROVED PUMP This invention relates to pumps, and more

particularly to positive displacement pumps.

Conventional positive displacement pumps are of relatively complex construction, incorporating a number of movable parts such as valves, balls, flaps, membranes. stators and the like, as well as numerous seals.

Consequently manufacture can be expensive and maintenance is regularly required.

It would be desirable to be able to provide a positive displacement pump of simpler construction than heretofore, incorporating significantly less moving parts and less prone to maintenance requirements.

According to the present invention there is provided a pump comprising a cylindrical housing having an inlet thereto and an opposed outlet therefrom, and a piston slidably mounted in the housing to be reciprocal therein between first and second endmost positions within first and second end regions respectively of the housing, characterised in that the piston has formed therein a first chamber which, with the piston moving from the first endmost position within the housing to the second endmost position within the housing. interconnects the inlet with the first end region of the housing, the piston being rotatable about the central longitudinal axis thereof whereby, when the piston 2 reaches the second endmost position and on rotation of the piston, the first chamber interconnects the first end region of the housing with the outlet during movement of the piston from the second endmost position back to the f irst endmost position.

Such an arrangement eliminates valves from the pump, as well as the balls, flaps, membranes, stators and the like referred to above. The only moving part is a simple piston which can be moved pneumatically, hydraulically, electrically or electromagnetically.

The pump of the invention can be made in any material capable of withstanding the internal pressures, the only seal being that for the piston shaft. In the case of an electromagnetic drive, the pump has no seals - a magnet may be embedded in the piston which would be reciprocated via an external magnet.

In one embodiment of the invention, the piston has formed therein a second chamber which, with the piston moving from the first endmost position within the housing to the second endmost position within the housing, interconnects the outlet with the second end region of the housing, and which, subsequent to rotation of the piston, and during movement of the piston from the second endmost position back to the first endmost position, interconnects the inlet with the second end region of the housing.

In a further embodiment of the invention there is 3 provided, externally of the housing, a feed line between the first end region of the housing and the outlet, the one end of the piston having mounted therein, to be reciprocal therewith, one end of a secondary piston, the other end of said secondary piston being slidably received within, to be reciprocal in, one end of said feed line whereby, on reciprocation of the piston, the secondary piston creates, alternately, positive and negative pressures within the feed line. By way of examples only, embodiments of the invention will now be described with reference to the accompanying drawings of which: Figs. 1 to 4 show a first pump according to the invention in various stages of operation, and Fig. 5 shows a second pump according to the invention. Referring to Figs. 1 to 4, a piston 2 is reciprocal in a housing 4 and has two chambers 6,8 therein connected to the pump chambers 10,12 respectively. with the piston 2 moving to the right as viewed in Fig. 1, the chamber 10 is filled with fluid. On completion of the stroke, the piston 2 is turned 180' as indicated in Fig. 2 and returns towards the starting position as shown in Fig. 3 whilst discharging the contents of chamber 10 and filling chamber 12. At the starting position shown in Fig. 4, the piston 2 is again turned 180' and the cycle re-continues. The pump inlet is referenced 14 and the outlet is referenced 16.

4 The pump can be manufactured in any material of construction. The only seal in the pump is the piston shaft seal 18. In the case of electromagnetically driven pumps, the pump is totally seal-less.

There is a further extension to the pump, namely for extremely accurate flow control by enabling the pump to suck back a portion of the main fluid already pumped.

According to the pump of this embodiment of the invention, a secondary piston 20 can be added which reciprocates with the main piston 2 as shown in Fig. 5.

During the upstroke, the main piston 2 fills the chamber under the piston, but at the same time effects a suction action through the secondary piston 20 which pulls some of the fluid back.

For every stroke of the main piston 2 there is therefore a small secondary return pull created by the secondary piston 20. By screwing the secondary piston 20 in or out of the main piston 2, the amount of return fluid can be regulated.

Claims

1. A pump comprising a cylindrical housing having an inlet thereto and an opposed outlet therefrom, and a piston slidably mounted in the housing to be reciprocal therein between first and second endmost positions within first and second end regions respectively of the housing, characterised in that the piston has formed therein a first chamber which, with the piston moving from the first endmost position within the housing to the second endmost position within the housing, interconnects the inlet with the first end region of the housing, the piston being rotatable about the central longitudinal axis thereof whereby, when the piston reaches the second endmost position and on rotation of the piston, the first chamber interconnects the first end region of the housing with the outlet during movement of the piston from the second endmost position back to the first endmost position.

2. A pump as claimed in claim 1 in which the piston has formed therein a second chamber which, with the piston moving from the first endmost position within the housing to the second endmost position within the housing, interconnects the outlet with the second end region of the housing, and which, subsequent to rotation of the piston, and during movement of the piston from the second endmost position back to the first endmost 1 6 position, interconnects the inlet with the second end region of the housing.

3. A pump as claimed in claim 1 in which there is provided, externally of the housing, a feed line between the first end region of the housing and the outlet, the one end of the piston having mounted therein, to be reciprocal therewith, one end of a secondary piston, the other end of said secondary piston being slidably received within, to be reciprocal in, one end of said feed line whereby, on reciprocation of the piston, the secondary piston creates, alternately, positive and negative pressures within the feed line.

4. A pump substantially as described with reference to and as illustrated by the accompanying drawings.