Temperature control of a pumped gas flow

Abstract

A heat exchanger for changing a temperature of a pumped gas flow and a pump comprising the heat exchanger is disclosed. The heat exchanger comprises: at least one tube configured to contain a flow of fluid; said at least one tube being at least partially embedded within a block of material; wherein said heat exchanger comprises mounting means configured to mount said heat exchanger adjacent to a gas port of a pump such that a least a portion of said heat exchanger extends into a path for gas flow flowing through said gas port; wherein the mounting means comprises a flange, the flange being configured to connect with the gas port of the pump, the block being mounted to the flange such that the block extends towards the rotor of the pump when the flange is connected with the gas port of the pump.

Claims

1. A vacuum booster pump comprising a modular heat exchanger for changing a temperature of a gas flow, the heat exchanger comprising: at least one tube configured to contain a flow of fluid; the at least one tube being at least partially embedded within a block of material, wherein the block is formed of a rigid, conductive material that holds and protects the at least one tube and conducts heat to the at least one tube; at least one heatsink, wherein the heatsink is shaped extruded and finned and wherein the heatsink is separate from the block of material; a thermally conductive material located between the heatsink and the block of material, the thermally conductive material is separate from the block of material and the heatsink, and wherein the heatsink is attached to the block of material and the thermally conductive material; and mounting means configured to mount the heat exchanger adjacent to a gas port of a pump such that a least a portion of the heat exchanger extends into a path for gas flow flowing through the gas port, wherein the mounting means comprises a flange, the flange being configured to connect with the gas port of the pump, the block being mounted to the flange such that the block extends towards at least one rotor of the pump when the flange is connected with the gas port of the pump.

2. The vacuum booster pump according to claim 1, wherein the heat exchanger is mounted centrally within the gas flow path when mounted adjacent to the gas port.

3. The vacuum booster pump according to claim 1, the heatsink comprises a plurality of heat transfer fins extending from the block, the plurality of heat transfer fins being configured to extend into the gas flow path when the heat exchanger is mounted adjacent to the gas port.

4. The vacuum booster pump according to claim 3, wherein the plurality of heat transfer fins extends towards the rotor of the pump when the flange is connected with the gas port of the pump.

5. The vacuum booster pump according to claim 3, wherein the block is mounted to the flange such that when mounted adjacent to the gas port of the pump, at least some of the plurality of heat transfer fins extend close to the at least one rotor of the pump, such that the at least some of the plurality of heat transfer fins are within 50 mm of the at least one rotor.

6. The vacuum booster pump according to claim 5, wherein the block is mounted to the flange such that when mounted adjacent to the gas port of the pump, at least some of the plurality of heat transfer fins extend to within 10 mm of the at least one rotor.

7. The vacuum booster pump according to claim 5, wherein the block is mounted to the flange such that when mounted adjacent to the gas port of the pump, at least some of the plurality of heat transfer fins extend to within 5 mm of the at least one rotor.

8. The vacuum booster pump according to claim 1, the heat exchanger comprising a plurality of heat transfer fins extending from the block, wherein the block and the plurality of heat transfer fins are shaped such that the block and the plurality of heat transfer fins extend further towards the at least one rotor towards a centre of the gas flow path than they do towards an edge of the gas flow path.

9. The vacuum booster pump according to claim 3, wherein the heat exchanger is configured to have substantially the same cross section perimeter as the gas port, wherein to have substantially the same cross section perimeter as the gas port, an outer perimeter of the heat exchanger is configured with a length that is 90% or more of the length of the perimeter of the gas port and adjacent to the gas flow path.

10. The vacuum booster pump according to claim 3, wherein said block and said plurality of heat transfer fins are formed of aluminium.

11. The vacuum booster pump according to claim 3, wherein the thermally conductive material comprises a sheet of graphite.

12. The vacuum booster pump according to claim 3, wherein the heat exchanger comprises a plurality of block modules with thermally conductive material between each block, the heatsink being attached to the plurality of block modules with thermally conductive material between the heatsink and the plurality of block modules.

13. The vacuum booster pump according to claim 1, wherein the mounting means comprises a fluid inlet and a fluid outlet for connecting to a fluid source.

14. The vacuum booster pump according to claim 1, wherein the heat exchanger comprises a cooler, and the flow of fluid comprises a flow of cooling fluid.

15. The vacuum booster pump according claim 3, the heat exchanger being mounted adjacent to a port of at least one stage of the vacuum booster pump such that the plurality of heat transfer fins from the heat exchanger extend into a flow of gas passing through the port.

16. The vacuum booster pump according to claim 15, wherein the heat exchanger comprises a cooler and the flow of fluid comprises a flow of cooling fluid, the heat exchanger is mounted adjacent to an exhaust of the vacuum booster pump.

17. The vacuum booster pump according to claim 16, wherein at least a portion of the gas is recirculated, the heat exchanger being arranged to provide cooling to both the exhausted and recirculated gas.

18. The vacuum booster pump of claim 1, wherein the block is a cast metal unit.

19. The vacuum booster pump of claim 1, wherein the vacuum booster pump is a Roots vacuum booster pump.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the present disclosure will now be described further, with reference to the accompanying drawings, in which:

(2) FIG. 1 illustrates a heat exchanger block and tubes according to an embodiment;

(3) FIG. 2 illustrates the heat exchanger of FIG. 1 with mounting flange according to an embodiment;

(4) FIG. 3 illustrates the heat exchanger mounted on the exhaust port of a booster pump according to an embodiment; and

(5) FIG. 4 shows a modular heat exchanger according to an embodiment.

DETAILED DESCRIPTION

(6) Before discussing the embodiments in any more detail, first an overview will be provided.

(7) A heat exchanger for pumped gases is provided. The heat exchanger is configured for mounting at a gas port of a pump such that it warms or cools the gas flowing through that port. The heat exchanger is configured so that at least a part of the heat exchanger and in some embodiments all of the heat exchanger is mounted within the gas flow, allowing for effective heat transfer between the heat exchanger and the gas. The tubes carrying the flow of heat exchange fluid are protected from the vibrations of the pump and the potentially harsh environment of the gas flow by being at least partially embedded in a block of material, which block provides rigid support for the pipes along at least 80% of the length of the pipes. This provides an effective yet compact arrangement.

(8) In some embodiments at least 80% of the cross section of the pipes are held within the block.

(9) The block may be of cast metal and in some embodiments has protrusions extending from the block supporting the pipes which protrusions or fins extend into the gas flow and increase heat exchange.

(10) The tubes may be cast within the block or pressed into it. In some cases the heat exchanger may be formed of modules, the tubes being supported by being pressed into block modules, which block modules have heat exchange fin modules bolted to them.

(11) FIG. 1 shows a heat exchanger 10 formed of cast metal according to an embodiment. The main block 20 has tubes 30 (shown separately) cast within the block, which tubes have an inlet 32 and outlet 34 for connection to a fluid source, allowing fluid to flow around the tubes within the heat exchanger.

(12) The cast metal heat exchanger 10 has a central block 20 in which the pipes are cast and heat exchange fins or protrusions 40 around the edge which increase the contact surface area with the gas flow 42. The central portion of the block 20 has through passages 24 allowing for the flow 42 of gas.

(13) FIG. 2 shows the cast metal heat exchanger 10 of FIG. 1, with a mounting flange 50, via which is configured to be mounted to a port of a pump not shown in FIG. 2). FIG. 3 shows heat exchanger 10 mounted on the exhaust port 56 of a booster pump 54, whereby the block and fins of the heat exchanger 10 extend towards 52 the rotors 58 of the pump 54. The cast metal heat exchanger is designed to fit within the gas flow path 42 such that it extends across most of the flow path and the surface of the heat exchanger 10 closest to the rotor is configured to lie within 45 mm of the rotor not shown in FIG. 3).

(14) FIG. 4 shows a modular heat exchanger 10 in the form of an aftercooler for a booster pump according to an embodiment. The heat exchanger 10 comprises a mating flange 50 configured to join with a vacuum booster exhaust. The flange 50 carries inlet 36 and outlet 38 channels for the input and output of fluid such as water as well as mounting points for the internal heat exchange components.

(15) In this embodiment two custom designed aluminium cooling blocks are provided with pressed in copper tubing 30 configured to carry the cooling water from the main modules of the heat exchanger. In the modular figure only one is shown for ease of illustration. Shaped extruded finned aluminium heatsinks 22 are bolted to the two cooling blocks with intermediate thermally conductive film in the form of a thin graphite layer 26 lying between the modular components. The blocks and fins are specifically shaped to be in close proximity to the vacuum pump rotors knot shown in FIG. 4) to provide efficient thermal cooling of the gas and of the pump rotors when mounted on the exhaust port knot shown in FIG. 4). In this regard as can be seen from the figures, the lower surface of the heat exchanger that extends towards the rotors comprises a middle portion 60 which extends further than the edge portions 62. This middle portion 62 extends into the space between the rotors of the pump knot shown in FIG. 4) providing effective cooling of the rotors as well as the exhausted and recirculated gas. The formation of this aftercooler 10 from modular components allows it to be manufactured from modules simply fixed together in some way such as by bolting or welding. The modular nature of the device 10 means that at least some of the components may be standard off the shelf components, or at least have applications in multiple vacuum pump heat exchangers of slightly different configurations.

(16) In this regard although in this embodiment there are two central blocks, two thin sheets of graphite 26 and two aluminium heat sinks 22, owing to the modular nature of this embodiment any number of different components may be used together according to the required size and application of the heat exchanger.

(17) Although illustrative embodiments of the disclosure have been disclosed in detail herein, with reference to the accompanying drawings, it is understood that the disclosure is not limited to the precise embodiment and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the disclosure as defined by the appended claims and their equivalents.