Hydraulically driven bellows pump

Abstract

A hydraulically driven diaphragm pumping machine (pump), in particular for water and difficult-to-pump materials, comprises at least two side-by-side pumping units. Each pumping unit comprises a hydraulically-driven pump cylinder (1,2) and a separate non-pump hydraulic drive cylinder (9,10). The pump cylinder (1,2) has a lower first end with a first inlet and outlet for fluid to be pumped and an upper second end with a second inlet and outlet for hydraulic fluid. The pump cylinder (1,2) contains a bellows (3,4) closed at its lower end and open at its upper end for communication with hydraulic fluid. The outside of the bellows (3,4) defines a space for fluid to be pumped. The bellows (3,4) of the pump cylinder (1,2) is arranged to be driven by hydraulic fluid supplied at its top end, in concertina like expansion and contraction to pump the fluid to be pumped adjacent the lower first end of the pump cylinder (1,2). The hydraulic drive cylinder (9,10) is placed side-by-side the pump cylinder (1,2). The hydraulic drive cylinder (9,10) has a lower first end associated with a hydraulic drive an upper second end containing hydraulic fluid communicating with the upper second end of the pump cylinder (1,2). The hydraulic drive terminates at its upper end with a drive piston (19,20) slidably mounted in the hydraulic drive cylinder (9,10). The hydraulic drives of the hydraulic drive cylinders (9,10) of the two pumping units are connected by a hydro-mechanical connection (25,27) designed to control drive of the hydraulic fluid to advance and retract the pistons (19,20) of each hydraulic drive cylinder (9,10).

Claims

1. A hydraulically driven diaphragm pumping machine suitable for pumping water and difficult-to-pump materials, the pump comprising at least two pumping units which are placed side-by-side one another, each pumping unit comprising: a hydraulically-driven pump cylinder (1,2) that has a lower first end with a first inlet and outlet for fluid to be pumped and an upper second end with a second inlet and outlet for hydraulic fluid, the pump cylinder (1,2) containing a bellows (3,4) closed at its lower end and open at its upper end for communication with hydraulic fluid, the outside of the bellows defining a space for fluid to be pumped, the bellows (3,4) of the pump cylinder (1,2) being arranged to be driven by the hydraulic fluid in concertina-like expansion and contraction to pump the fluid to be pumped adjacent the lower first end of the pump cylinder (1,2); and a non-pump hydraulic drive cylinder (9,10) which is separate from and is located outside the pump cylinder (1,2), the non-pump hydraulic drive cylinder and the pump cylinder being placed side-by-side one another, the non-pump hydraulic drive cylinder (9,10) having a lower first end associated with a hydraulic drive and an upper second end containing hydraulic fluid communicating with the upper second end of the pump cylinder (1,2), said non-pump hydraulic drive cylinder (9,10) terminating at its upper end with a drive piston (19,20) slidably mounted in the non-pump hydraulic drive cylinder (9,10) for driving said hydraulic fluid at the upper end of the non-pump hydraulic drive cylinder (9,10), wherein hydraulic drives of the non-pump hydraulic drive cylinders (9,10) of two side-by-side pumping units are connected by a hydro-mechanical connection (25,27) arranged to control the drive of hydraulic fluid to advance and retract the drive pistons (19,20) of both non-pump hydraulic drive cylinders (9,10).

2. The hydraulically-driven diaphragm pumping machine of claim 1, wherein each non-pump hydraulic drive cylinder (9,10) is hereinafter referred to as first hydraulic drive cylinder, and the hydraulic drive of each first hydraulic drive cylinder comprises a second hydraulic drive cylinder (13,14) of smaller diameter than the first hydraulic drive cylinder located under and hydraulically connected to the first hydraulic drive cylinder (9,10), the drive piston (19,20) being a first piston fitting in the first hydraulic-cylinder connected by a rod (17) to a second piston (15,16) of smaller diameter in the second hydraulic drive cylinder (13,14).

3. The hydraulically-driven diaphragm pumping machine of claim 2, wherein the hydraulic drive of the first hydraulic drive cylinders (9,10) comprises means for supplying hydraulic fluid to the second hydraulic drive cylinder (13,14) above and below the second piston (15,16) of the second hydraulic drive cylinder.

4. The hydraulically-driven diaphragm pumping machine of claim 1, wherein two side-by-side pumping units are mounted on a support (50) with the pump cylinders (1,2) side-by-side on a front part of the support (50) and the hydraulic drive cylinders (9,10) side-by-side on the support behind the pump cylinders (1,2).

5. The hydraulically-driven diaphragm pumping machine of claim 4, further comprising discharge valves (7,8) and suction valves (5,6) for discharging and inputting material to be pumped out of and into the pump cylinders (1,2), said discharge valves and suction valves being located on the front of the support (50) in front of and at the bottom of the pump cylinders (1,2).

6. The hydraulically-driven diaphragm pumping machine of claim 1, wherein said hydro-mechanical connection (25,27) is located between the hydraulic drive cylinders (9,10) of two side-by-side pumping units.

7. The hydraulically-driven diaphragm pumping machine of claim 1 wherein the bellows (3,4) and drive piston (19,20) of each pumping unit are driven synchronously, and the drive pistons (19,20) of two side-by-side pumping units are driven asynchronously.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be further described with reference to the accompanying drawings, in which:

(2) FIG. 1 is an overall schematic diagram of an exemplary embodiment of a pump according to the invention;

(3) FIG. 2 is a perspective view of the pump of FIG. 1 showing the two pumping units side-by-side;

(4) FIG. 3 is a cross-section through the pump cylinder and the hydraulic drive cylinder of one pumping unit wherein the bellows is pushed fully down;

(5) FIG. 4 is a schematic top plan view of the pump; and

(6) FIG. 5 is a diagram of the scheme of switching.

DETAILED DESCRIPTION

(7) The invention provides a hydraulically driven diaphragm pumping machine (pump), in particular for water and difficult-to-pump materials. In this example, the pump comprises two side-by-side pumping units but multiple pumping units are possible. Each pumping unit comprises a hydraulically-driven pump cylinder or bellows cylinder 1,2 and a separate hydraulic drive cylinder 9,10 located side-by-side to the pump cylinder 1,2, as shown.

(8) The pump cylinder or bellows cylinder 1,2 has a lower first end with a first inlet and outlet for fluid to be pumped and an upper second end with a second inlet and outlet for hydraulic fluid. In either case, there can be a single inlet/outlet or a separate inlet and outlet. The pump cylinder 1,2 contains a bellows 3,4 closed at its lower end and open at its upper end for communication with hydraulic fluid. The outside of the bellows 3,4 defines a space for fluid to be pumped. The bellows 3,4 of the pump cylinder 1,2 is arranged to be driven by hydraulic fluid supplied at its top end, in concertina like expansion and contraction to pump the fluid to be pumped adjacent the lower first end of the pump cylinder 1,2.

(9) The hydraulic drive cylinder 9,10, placed side-by-side the pump cylinder 1,2, has a lower first end associated with a hydraulic drive and an upper second end containing hydraulic fluid communicating with the upper second end of the pump cylinder 1,2. The hydraulic drive terminates at its upper end with a drive piston 19,20 slidably mounted in the hydraulic drive cylinder 9,10. The hydraulic fluid at the top of the hydraulic drive cylinder 9, 10 is located above the drive piston 19,20 to be driven thereby.

(10) The hydraulic drives of the hydraulic drive cylinders 9,10 of the two pumping units are connected by a hydro-mechanical connection 25,27 designed to control the drive of the hydraulic fluid to advance and retract the pistons 19,20 of each hydraulic drive cylinder 9,10.

(11) At their tops, the pump or bellows cylinder 1,20 and the adjacent hydraulic drive cylinder 9,10 are connected by a conduit 48 for hydraulic fluid.

(12) Preferably, the hydraulic drive of each hydraulic drive cylinder 9,10 (first hydraulic drive cylinder) comprises a second hydraulic drive cylinder 13,14 of smaller diameter than the first hydraulic drive cylinder 9,10, located under and hydraulically connected to the first hydraulic drive cylinder 9,10. The drive piston 19,20 is a first piston fitting in the first hydraulic-cylinder 9,10 connected by a rod 17 to a second piston 15, 16 of smaller diameter in the second hydraulic drive cylinder 13,14. The hydraulic drive of the hydraulic drive cylinder 13,14 comprises means 27 for supplying hydraulic fluid to the second hydraulic drive cylinder 13,14 above and below the second piston 15,16 of the second hydraulic drive cylinder 13,14.

(13) In the illustrated embodiment, the two side-by-side pumping units are mounted on a rectangular support 50 with the pump cylinders 1,2 side-by-side on a front part of the support 50 and the hydraulic drive cylinders 9,10 side-by-side on the support 50 behind the pump cylinder 1,2. Of course, the pump can be mounted on supports of any suitable shape and size, and with any suitable layout.

(14) The pump usually further comprises discharge valves 7,8 and suction valves 5,6 for discharging and inputting material to be pumped out of and into the pump cylinders 1,2. As shown in FIG. 2, the discharge valves and suction valves can be located on the front of the support 50 in front of and at the bottom of the pump cylinders 1,2.

(15) As shown in FIG. 3, the upper part of the pump cylinder 1,2 can be provided with an air vent 46 for venting air/gas from the material being pumped.

(16) The means for supplying hydraulic fluid to the second hydraulic drive cylinder 13,14 can be a hydromechanical connector 27 located between the hydraulic drive cylinders 9,10 of the two side-by-side pumping units.

(17) In greater detail, the pump consists of two bellows cylinders 1,2 which contain one bellows 3, 4 in each cylinder and two valves: suction valve 5, 6 and discharge valve 7, 8. The pump also has two piston hydraulic drive cylinders 9, 10 hydraulically connected with bellows cylinders 1, 2. Each of the hydraulic drive cylinders 9, 10 comprises a hydraulic power cylinder 11, 12 and a second cylinder 13, 14 whose piston 15, 16 is connected to the hydraulic power cylinder piston 19, 20 by rod 17. Rod end sections 21, 22 of cylinders 13, 14 are hydraulically connected to a common pneumo hydraulic accumulator 23.

(18) The pump also comprises a piston hydraulic fluid control valve 26 connected in cylinder 9,10 below the piston 19,20 and a piston limiter 24 installed between the pneumohydraulic accumulator 23 and hydraulic drive cylinders 13, 14. It also includes a mechanically operated hydraulic power switch 25, hydraulically connected to the hydraulic fluid control valve 26, and mechanically connected by traction rod 27 with the two piston hydraulic drive cylinders 9, 10. The overall pumping machine has a piston hydraulic pump 28 hydraulically connected to the hydraulic fluid control valve 26. The driving power of all units may be either electric, gas or diesel drive (not shown). The pump is supplied with an oil tank in the form of low-pressure accumulator 29 (or reservoir), as well as high-pressure accumulator 30, to alleviate the pressure fluctuations when switching the oil pipeline system 31 and water suction manifold 32 and water

(19) delivery manifold 33. For cleaning and cooling oil, the main hydraulic pump 28 is equipped with an auxiliary hydraulic pump 34 and also purification and cooling system 35.

(20) As mentioned, the hydro-mechanical connection 25,27 can be located between the hydraulic drive cylinders 9,10 of the two side-by-side pumping units.

(21) The bellows 3,4 and drive-piston 19,20 of each pumping unit are driven synchronously, and the drive pistons 19, 20 of the two pumping units are driven asynchronously, that is the direction of movement of the pistons 19,20 of the two pumping units does not reverse at the same time.

(22) As illustrated in FIG. 2, the rear part of the support 50 can be occupied by auxiliary equipment like a cooling system (heat exchanger) 35.

(23) The described pump can for example have a maximum operating pressure of say 34.5 MPa, a maximum through flow of at least 500 and possibly 1000 l/min, a minimum absolute pressure upon an input at the maximum productivity of 0.02 MPa, and a power of 200-240 kW. Generally, a pump according to the invention can work at much higher or lower values.

Pump Operation

(24) The pump is connected to water or other fluid material to be pumped which is intaken in the intake manifold 32. The material being pumped is intaken into pumping cylinders 1,2 when the bellows 3,4 moves up under hydraulic drive. When the bellows 3,4 are hydraulically driven down, the pumped material is expelled and is forced out via the discharge manifold 33.

(25) The mechanically operated hydraulic power switch 25 can be in one of two stable positions A or B. When it is in position A, high pressure liquid flows from the piston hydraulic pump 28 through the pipeline 36 and the hydraulic fluid control valve 26 to the rod end C2 of hydraulic power cylinder 12, and moves its piston 20 upward. The fluid from cavity D2 is expelled into the inner cavity E2 of bellows 4, moving the partition plate 37 of the latter down. Herewith the pumped fluid is forced out into the manifold 33 through discharge valve 8. The piston 16 of cylinder 14 moves also up forcing the fluid from the rod end 22 of cylinder 14 into the rod end 21 of cylinder 13. The latter in turn, moving down, moves also down the power cylinder 11's piston 19, thus forcing out liquid from its rod end CI to the accumulator 29 (or cistern). Under the influence of pressure in accumulator 23, the pistons of cylinder 9 take the lead over the pistons of cylinder 10 in relocation on the value proportional to the volume of piston limiter 24. Owing to this, they reach the end of their power stroke earlier than the cone bushing 38 of piston 16 of cylinder 14 reaches a roller 39 (the start of switching the hydraulic power switch 25 from A to B). At the start of the switching, the bushing 38 starts to activate the roller 39 moving its rod 40 and rod 27 to the left, leading to switching the hydraulic power switch 25 to position B, which will hydraulically switch the hydraulic fluid control valve 26. According to the switching scheme shown in FIG. 5, switching of valve 26 takes place in such a way that firstly the drain channel G1 of cylinder 9 closes, then the inlet channel HI of high pressure cylinder 9 opens and high pressure inlet channel H2 of cylinder 10 closes simultaneously. This ensures smooth switching and minimal pressure oscillations in the pressure manifold 33.

(26) After closing the high-pressure inlet channel H2, the drain channel G2 of cylinder 10 opens. Here the switching process ends. In the period from t1 to t2, see the switching diagram, FIG. 5 which shows the relative switching times of the two cylinders 9,10, when both drain channels G1, G2 are closed, the hydraulic drive pump is powered from the accumulator 29 (or reservoir).

(27) Also in this period, both pressure channels HI, H2 are open and both pistons 19, 20 of power cylinders 11, 12 move upward, the working fluid from cylinders 13, 14 is replaced into hydropneumatic accumulator 23 through piston-limiter 24 which returns to its previous starting position. After opening the drain channel G2 of cylinder 10 the fluid from hydropneumatic accumulator 23 rapidly moves piston 20 of power cylinder 12 downwards under a slight excess pressure. The transfer occurs within the volume of the piston-limiter 24. This ensures asynchronous operation of the two pumping units whereby the final operating position of the working piston 20 of cylinder 12 is earlier than piston 19 of cylinder 11. Later when the bushing 41 of the piston 13 of roller 42 (start of switching), the switching occurs similarly. The asynchronous operation of the two hydraulic drive cylinders can be seen from the switching diagram, FIG. 5.