EP2224132B1

EP2224132B1 - Pumping device

Info

Publication number: EP2224132B1
Application number: EP10152003.9A
Authority: EP
Inventors: Johann Carl Rudolf Van Der Hart
Original assignee: Jcr Van Der Hart Holding Bv
Current assignee: Jcr Van Der Hart Holding Bv
Priority date: 2009-01-28
Filing date: 2010-01-28
Publication date: 2020-01-08
Anticipated expiration: 2030-01-28
Also published as: EP2224132A3; EP2405138B1; EP2224132A2; EP2405138A3; EP2405138A2

Description

Background of the invention

The invention relates to a pumping device. Especially for pumping fluids which have been purified often membrane pumps are applied. The advantage of a membrane pump is that there is a gas tight separation from the surrounding; because of this no contamination by foreign (gas) molecules will occur. These pumping systems are expensive and complex.
Alternatively, in some applications positive displacement pumps may be applied. Known in the art are amongst others the DLE series pumps from the company Maximator, or pumps from Haskel. However, due to the reciprocating movement of the plunger in these plunger pumps or booster pumps, alternatingly underpressure and overpressure will occur. There is a real possibility that this underpressure will draw in unwanted molecules via the plunger sealings and past the cylinder sealings. It is even very well possible to draw in air, which in combination with highly ignitable media may lead to a potential risk of explosion.
In order to reduce this risk to a minimum, manufacturers of pumps prescribe to only use a selection of pumpable media for their pumps, and to operate these pumps at a higher pressure-bandwidth. Furthermore, a known pump device is described in US 5,520,169 .
In actual practice, it was found that (unwanted) too low prepressure can easily occur. Pumping pure media and small molecules therefore is not recommended. Unfortunately, due to these facts the choice will fall on the more expensive membrane booster pump for many applications.
A liquid and/or gas booster pump which works according to the plunger principle generates heat at the compression cycle. When pumping larger molecules, so much heat is even generated that overheating can lead to very unwanted situations. A lubrication film which may be present in order to protect sealing rings may burn, resulting in the break-down of amongst others the plunger sealing, cylinder sealing, damage to the plunger and the cylinder wall, check valves, and the like. Furthermore, the combustion products will gas out in the medium which is to be pumped and lead to contamination. With heavy loads on the booster pump, this risk will increase even further.
In order to remedy this problem, such booster pumps are equipped with cooling ribs or the cycle-air of the booster is led into a double wall around the high pressure cylinder wall which causes it to cool down. Under standard circumstances this can be sufficient and the operational temperatures of those systems are set to remain within a bandwidth of 30 to 90 degrees Celsius. There are however many situations in which an active control of the compression chamber temperature and also of the medium to be pumped is important. One might think of a medium which becomes instable at a higher temperature, which can reach an ignition temperature or which can go outside set boundaries.
There is therefore room for improvements of the well-known pumps.

Summary of the invention

The invention seeks to provide an improved pumping device.
The invention further or additionally aims to provide a pumping device which is suitable for pumping purified fluids like gases.
The invention to this end provides a pumping device according to claim 1.
We have implemented a number of modifications to the pumping device, in this document also indicated as plunger booster pump, which modifications can prevent contamination of the medium.
The basic principle of the plunger booster pump is a composition of two rod coupled plungers, in which a large compressed air driven plunger drives the coupled smaller cylinder. The amplification of the compression force is used to pump medium at the other side of the booster.
As the plungers go back and forth there is a breathing segment provided between both systems; in an embodiment this chamber is in a pressure controlled manner coupled to the fluid that is to be pumped.

In summary

The above explained cooling provides temperature control having the effect of:

preservation and lifespan of the pump
broader application for larger molecules which generate more friction
keeping sensitive media within process temperature
preventing unwanted outgassing products (combustion products) from entering the media stream
preventing softening of sealing rings

The above explained gas ballast provides control of leaking in, having the effect of

retaining the purity of the medium which is to be pumped
broader application with larger molecules (which can leak more easily past sealing)
preventing potentially dangerous gas mixtures to occur
enabling indication that sealings of the media pumping system deteriorates in functionality

And because of this unforeseen calamities may be prevented.
A commercially broadened application of plunger booster pump devices in the direction of membrane pumps is hereby realized.
The basic principle of the pumping device, here also called plunger booster pump, comprises, as already explained, an assembly of two rod coupled plungers, in which a larger, compressed air driven ("low pressure") plunger drives a smaller, coupled ("high pressure") plunger.
The amplified compression force that is in this manner generated during operation, is used to pump a fluid of the pumping device.
As the plungers go back and forth, a breathing segment is provided between both systems. We can fill this breathing segment or chamber with a part of the medium to be pumped, like a gas, and maintain it at a small overpressure (by means of a regulator). Any pressure fluctuations which may occur can be facilitated using a relatively small expansion vessel.
On balance - in case of failure of the provided plunger sealings - sucking in of for instance air through the high pressure plunger will effectively be ruled out.
A second leaking in could be possible because of failure of sealings at the compression side of the high pressure cylinder tube, and due to this false air can be sucked in.
This can be solved by a (either or not existing) second tube, which will normally be surrounded with compressed air, and closing is off at one side and connect the chamber that is created in this manner to the above referenced low pressure fluid buffer barrel, and via the active pressure control, an effective guarding of the functionality of the pumping seals is realized.
A controller may also be included which monitors whether the set pressure values in the breathing segments of the double cylinder wall of the high pressure cylinder do not become too high or too low. This can indicate a starting sealing problem and can be reported before an unwanted situation occurs.
This modification will therefore not only provide a preservation of the purity of the medium to be pumped, it also prevents potentially dangerous mixtures (which will furthermore be compressed), it allows to monitor and report the mechanical status of the plunger booster pump.
An active temperature control will allow a broader application of these pumping systems. In order to realize this we provided a cooling spiral around the high pressure cylinder. This cooling spiral will be able to actively cool the compression chamber and the plunger.
The end part of the high pressure cylinder comprises a plate with several additional channels which are provided by us and through which (with the help of some special coupling pieces, we can lead a second cooling conduit; also the high pressure exit path can be cooled because of this.
The first mentioned inner spiral cooling is to be applied tightly around the inner tube, in order to improve transmission of heat.
In the above-mentioned booster end plate, a temperature sensor (and possible redundant second sensor) has been inserted. This will control a cooling valve in order to maintain the desired operating temperature, by means of a programmable temperature controller.
For the completion of the cooling system there is a (locally provided) cooling machine; in an example which is not part of the claimed subject-matter it thus provides a stand alone cooling application or cooling device and does not need to be connected to an external cooling.
An example further relates to a temperature control device for a pumping device as described above, but which is outside of the scope of the present claims. In particular this device provides a conversion kit for an existing pump of the described type. This kit comprises a cooling spiral, a casing for the high pressure cylinder, a temperature sensor and a control- or monitoring unit as described above. By means of the casing it is easy to notice leakage in the pump.
It will be clear that the different aspects mentioned in this patent application can be combined and/or separately qualify for a divisional patent application.

Brief description of the drawings

The drawings show in:

Figure 1: a systematic overview of the pumping device according to the invention;
Figure 2: a side view of the pumping device according to the invention;
Figure 3: a further side view of the pumping device of figure 2;
Figure 4: an exploded view of the pump of figure 2;
Figure 5: a further exploded view of figure 4 in more detail;
Figure 6: a detail of the end plate of figure 4;
Figure 7: an exploded side view of figure 4;
Figure 8: a top view of figure 6;
Figure 9: a series of pumps taken apart;
Figure 10: a further detail of figure 8;
Figure 11: a side view with outer tube;
Figure 12: an inner view of the pumping device of figure 2;
Figure 13: a further inner view of figure 2;
Figure 14: a detail of the connection of the pumping device of figure 2.

Description of embodiments

Figure 1 shows a schedule of a pumping device with a cooling provision. A first low pressure plunger pump is provided with a first plunger in a first cylinder which is here mechanically coupled to a second plunger with a smaller surface area and which is moveable in the second cylinder. The casing of the second cylinder is provided with a casing. This casing is provided with an inlet for the fluid which need to be pumped, usually a gas, under pressure.
An active temperature control will allow a considerably broader application of such a pumping system.
In order to provide this we have provided a cooling spiral as is shown in Figure 6 around the high pressure cylinder, see Figure 9. This cooling spiral will be able to actively cool the compression chamber and the plunger.
The end part of the high pressure cylinder comprises a plate in which a number of additional channels, as is shown in Figures 5 and 10, are provided by us through which we (using special coupling parts, see Figure 14) can lead a second cooling conduit, as is shown in Figure 8 and 7. The high pressure outlet can be cooled by this as well.
The aforementioned inner cooling spiral is in an embodiment provided tightly around the inner tube or inner housing, see Figures 13 and 11, in order to optimize heat transmission.
In the aforementioned booster end plate a temperature sensor (and possibly a redundant second sensor for securing purposes) have been provided, see Figure 3 and 9. This will, through a programmable temperature controller, control a cooling valve in order to maintain the desired operational temperature.
To complete the cooling system a small (locally provided) cooling device is provided; this thus relates to a stand alone cooling device and needs no connection to an external cooling, see Figure 4.
We have been able to reduce and keep stable an uncontrolled temperature of more than 120° C to 20° C, using a 6 ° C cooling medium.
The mentioned gas ballast can facilitate gas qualities up to 6.0 (99,9999%) purity.
In order to improve the sealing between the booster end plate (Figure 11) and the rim of the outer tube of the gas ballast, a sealing is provided, not shown in the Figures. In an embodiment the end plate can be provided with a circumferential groove that is provided with a sealing ring, for instance made of PTFE. The rim of the outer tube can be provided with a groove which connects to the sealing ring. Alternatively, one of the parts of the plate or outer tube can be provided with a sharp edge which, when the parts are screwed or drawn, e.g. using the pull rods (see for instance Fig. 9), tight to each other, cut into the other part and thus provide a sealing.
It may be clear that the description above is included to illustrate functioning of the preferred embodiments of the invention, and not to limit the scope of protection.

REFERENCE NUMBERS

HP = High pressure
LP = Low pressure
1. booster
2. media intake LP
3. HP outlet
4. buffer
5. pressure control
6. temperature controller
7. valve
8. inter cooler
9. external allarm
9'. external alarm
10. common cool tube inlet/return
11. booster end plate
12. gas ballast inlet around high pressure plunger (external safety)
13. gas ballast inlet below high pressure plunger (internal safety)
14. overview of assembly of double gas balast and duo coolingsystem on booster pump
15. outer tube for gas ballast (primed)
16. booster end plate cooling system
17. cooling system couplings through booster head by means of reversed end coupling
18. looped cooling system for booster tube
19. cooling spiral tube end
19'. cooling spiral return tube end
20. connection booster tube cooling system through and on the booster end plate
21. location of through-passage for the cooling system
22. through passage in booster end plate for cooling system
23. cooling spiral booster tube system
24. side view of booster tube cooling system
25. end view of booster tube cooling system tube
26. bolt holes booster end plate
27. high pressure booster tube
28. finished temperature protection /control & internal / external gas ballast for purity safeguard
29. temperature sensor for cooling system control
30. top view of booster end plate recesses
31. passage for cooling spiral inlet
31'. passage for cooling spiral return
32. detailed side view of booster tube cooling system (incl. external gas ballast tube)
33. external gas ballast / cooling space
34. high pressure plunger
35. double wall around high pressure cylinder
36. bottom view of inside of double coiled spiral inside (high pressure booster tube has been removed, cooling system couplings through booster head)
37. space for wall thickness of the high pressure booster tube
38. special coupling cooling conduit system coupling through booster head via reversed end coupling (for tube inlet & outlet)
39. negative ferrule sealing
40. tube passage (cooling conduit couplings)

Claims

Pumping device comprising a first low pressure plunger (LP) with a first plunger surface area and which is up and down moveable in a first cylinder, and a functionally coupled second, high pressure (HP) plunger with a second, smaller plunger area and which is moveable in a second cylinder, the second cylinder having a fluid inlet (2) and a fluid outlet (3) for a fluid to be pumped, said first plunger adapted to, in operation, drive the second plunger causing in operation an amplification of a compression force for pumping the fluid, wherein further a breathing segment is provided between both plungers, characterized in that a space of the breathing segment is in fluid connection coupled with the inlet (2) of the fluid to be pumped, via a regulator (5) that is adapted to maintain, in operation, a small overpressure on the breathing segment.
Pumping device according to claim 1, further comprising an expansion vessel (4) which is a buffer vessel, wherein the breathing segment, in order to absorb pressure fluctuations in operation, is in fluid connection with said expansion vessel (4), wherein the expansion vessel further is in fluid connection with the regulator.
Pumping device according to claim 2, in which the second cylinder is provided with a second, casing tube which is closed off at one end, thus providing a chamber which is in fluid connection with the buffer vessel.
Pumping device according to claim 3, further comprising a controller for monitoring if a set pressure value in the breathing segment and/or a cased space of the breathing segment remains within boundary values.
Pumping device according to any one of claims 1-3, further comprising a controller for monitoring if a set pressure value in the breathing segment remains within boundary values.