WO2010034312A1

WO2010034312A1 - A pump housing for an electromagnetic pump and a method of assembling a cooling circuit comprising the pump housing

Info

Publication number: WO2010034312A1
Application number: PCT/DK2009/000210
Authority: WO
Inventors: Martin Kloster
Original assignee: DANAMICS APS
Current assignee: DANAMICS APS
Priority date: 2008-09-29
Filing date: 2009-09-18
Publication date: 2010-04-01
Anticipated expiration: 2011-03-29
Also published as: DK200801351A

Abstract

When, according to the invention, the pump housing (1) for an electromagnetic pump (2) for a cooling circuit is arranged such that the base part (6) of the pump housing is equipped with pipe openings (8, 9), which lead from the lower side (14) of the base part perpendicularly into the channels (10) of the pump housing, it is ensured that the cooling circuit may be established with a single length of pipe (3), whose pipe ends (16) are introduced into the pipe openings (8, 9) and are soldered. It is ensured at the same time that the circuit may be established with just two solderings. This results in a significant reduction of the costs of manufacturing a cooling circuit.

Description

A PUMP HOUSING FOR AN ELECTROMAGNETIC PUMP AND A METHOD OF ASSEMBLING A COOLING CIRCUIT COMPRISING THE PUMP HOUSING

The invention relates to a pump housing for an electromagnetic pump for the propulsion of an electrically conductive liquid in pipes, in particular for the cooling of electric components, wherein the pump housing, together with the pipes, forms a closed circuit with which a heat exchanger and a cooling plate are connected, and wherein the pump housing comprises a base part and a lid part, and the base part additionally comprises at least two pipe inlet openings and at least two pipe outlet openings arranged at opposed ends of the base part. Further, the interior of the base part is divided into a plurality of channels of inwardly protruding barriers, and each channel extends between a pipe inlet opening and a pipe outlet opening. The barriers extend between the channels from the two ends of the base part, where the pipe openings are arranged, and inwards toward the centre of the base part, wherein the electrodes are arranged on opposed sides of the base part perpendicularly to the channels.

Moreover, the invention relates to a method of assembling a cooling circuit in which the pump housing according to the invention is incorporated.

The prior art

The inventor's own Danish Patent Application PA 2007 01817 discloses an electromagnetic pump comprising a pump housing which is adapted to be inserted into a cooling circuit. The pump housing is equipped with channels, barriers and electrodes.

The pipe connections of the pump housing are arranged on opposed sides of the housing, and the liquid flow runs in a straight line from a pipe con- nection on one side, through a channel, to a pipe connection on the other side. It has been found that precisely this configuration of the housing is not very desirable for reasons of function and production.

The small dimensions of the housing mean that there is an undesired power loss to the pipes, which causes an increased load of the power supply to the IC circuits.

In order to be able to assemble the pipe system with the pump housing, the heat exchanger and the cooling plate, it is necessary to provide the pipes with bends at the top and at the bottom of the cooling circuit and with a soldered joint on the pipes at the bottom of the cooling circuit, which results in high costs of production.

The patent document US 2007/0053153 relates to an electromagnetic pump, where the pump is used in a cooling circuit for the cooling of electric components, where the liquid flow runs in a straight line from a pipe connection on one side of the pump housing, through a channel, to a pipe connection on the other side of the pump housing. The cooling circuit com- prises pipe bends and a plurality of solder joints and is therefore expensive to produce.

The patent document US 6,146,103 relates to an electromagnetic micro- pump, where the pipe inlet and the pipe outlet are arranged on a side face of the pump housing at a right angle into the channel. The micropump is made of special materials and by a special method and is designed to serve as a microactuator, such as a micropump, micromixer, microvalve, or as a sensor, such as a microflow meter or viscosity meter. The pump is unsuitable for operation in a cooling circuit. The object of the invention

It is the object of the invention to remedy these drawbacks, and this is achieved in that the pipe inlet openings and pipe outlet openings of the pump housing are arranged on the lower side of the base part and point at an essentially right angle into channels in the interior of the base part, and in that the spacing between an associated pipe inlet opening and pipe outlet opening corresponds to the spacing between the pipe ends of the pipes for the closed circuit.

When the pump housing is arranged as stated in claim 1 , it is surprisingly and advantageously ensured that the manufacturing costs may be reduced considerably, it being now possible to provide the pipes for the cooling circuits from a single pipe which is bent in U-shape and is cut to the desired length. This also reduces the number of bends and the number of solder- ings on the pipes compared to the prior art.

This structure of the pump housing moreover means that the pump housing has a size which at least corresponds to the spacing between associated inlet and outlet openings, thereby proportionately increasing the resistance in the bottom and the walls of the housing from the electrodes and out to the pipe inlet and pipe outlet, such that the flow will run through the circulating liquid between the electrodes to a greater degree.

When, as stated in claim 2, an angle between the pipe openings and the channels of the housing greater than ninety degrees, but smaller than one hundred and twenty degrees may be selected, it will be possible to configure the housing with a curvature.

When, as stated in claim 3, the lid part is equipped with deflection devices immediately above each pipe inlet and pipe outlet, it is ensured that the liquid may more readily pass the bend between pipes and channels. This ensures that the liquid flow runs without any turbulence of importance.

When, as stated in claim 4, the electrodes are configured as outwardly ex- tending pins, one of which is configured as a pipe, it is ensured that good flow connection options are provided, and simultaneously that a filling pipe for the conductive cooling liquid is at disposal.

When, as stated in claim 5, the base part and the lid part are made of stainless steel, it is ensured that the housing is resistant to corrosive gases and liquids, and it is moreover ensured that the housing may be made with the desired tolerances by means of machine tools.

When, as stated in claim 6, the base part is injection-moulded in stainless steel, it is ensured that larger batches of the housing may be produced at considerably reduced costs.

When, as stated in claim 7, the base part and the lid part are made of sintered metal, it is ensured that larger batches of the housing may be pro- duced at considerably reduced costs.

When, as stated in claim 8, the base part and the lid part are made of pressed metal sheeting, the advantages stated with respect to claim 5 or 6 are achieved, and it is moreover ensured that the manufacturing costs may be reduced.

Finally, as stated in claim 9, it is expedient to join the base part and the lid part hermetically by soldering or gluing.

Moreover, it is advantageous to assemble a cooling circuit with an electromagnetic pump comprising a pump housing according to any one of claims 1 - 9 as stated in claims 10, 11 , 12 and 13.

The drawing

Preferred exemplary embodiments will now be described more fully with reference to the drawing, in which

Fig. 1a shows a perspective view of a cooling circuit which is driven by an electromagnetic pump having a pump housing accord- ing to the invention,

Fig. 1 b shows a lateral view of fig. 1a,

Fig. 2 shows a lateral view of a cooling circuit having an electromag- netic pump according to the prior art,

Fig. 3 shows a perspective view of the base part for the pump housing according to the invention, and

Fig. 4 shows a section through a channel in the base part and the lid part for the pump housing, seen from the side.

Description of the exemplary embodiments

Exemplary embodiments shown in fig. 1 , fig. 2, fig. 3 and fig. 4, respectively, will be described below.

Fig. 1 shows a perspective view of a cooling circuit having an electromagnetic pump 2 equipped with a pump housing 1 according to the invention. The circuit is shown assembled, and, in addition to the pump housing, the figure shows a plurality of pipes 3, a cooling plate 5 and a heat exchanger 4. The pump housing consists of a base part 6 and a lid part 7. All joints with connection to the coolant must be made hermetically.

The pipes 3 are made of a relatively soft metal alloy having good heat con- ductive properties and are cut to the desired length before being bent into U-shape. The pipe ends 16 shown in fig. 1 b, which are to be mounted in the pipe openings in the base part of the pump housing, are deburred and cleaned of impurities, so that a soldering/gluing process may be performed in connection with the assembly of the cooling circuit.

The cooling plate 5 is made of a metal alloy having good heat conductive properties, such as e.g. a copper alloy. Grooves dimensioned to receive the cooling pipes 3 are milled in the plate.

The heat exchanger 4 consists of a plurality of punched cooling fins of aluminium, which are hooked together to a stack by means of locking devices punched in the edges of the fins. The heat exchanger is equipped with a plurality of punched and pressed holes, so that the stack may be pressed at the same time down over the pipe ends 16 of the pipes when the cooling circuit is assembled.

Fig. 2 shows the prior art with a cooling circuit having an electromagnetic pump. The cooling circuit includes three lengths of pipe, all of which are equipped with a bend, and which require a joint just above the cooling plate. The shown configuration of pump housing and pipe system tells that assembly of this circuit involves a plurality of working operations which are time-consuming.

The pump housing according to the invention is shown in fig. 3 and fig. 4. The housing 1 comprises a base part 6 and a lid part 7. The base part is provided with a recess 17, which is configured to receive the lid part. A plu- rality of pipe inlet openings 8 and pipe outlet openings 9 are provided on the lower side 14 of the base part.

The openings 8, 9 are configured to receive the pipe ends 16 of the pipes 3 and lead into channels 10 at an essentially right angle. The interior of the base part is divided into a plurality of channels 10 of inwardly extending barriers 11. Each channel runs between associated pipe openings 8, 9. The barriers extend between the channels from the two ends of the base part, where the pipe openings are provided, and inwards toward the centre of the base part, where support for two electrodes 12, 13 is shown. The barriers are interrupted here, so that the flow path I between the electrodes, which are arranged on opposed sides of the base part perpendicularly to the channels, is unobstructed.

The lid part 7 is equipped with deflection devices 15, which are arranged on the lid part in a position which is directly above the pipe openings. The deflection devices are introduced to reduce the flow resistance and turbulence, if any, when the liquid passes through an angular bend of ninety degrees from the pipes and into the channels.

When the pump housing is configured as described above, it is ensured that the costs of manufacturing cooling circuits having an electromagnetic pump are reduced, and that the undesired flow losses are reduced at the same time.

The pump housing 1 is shown and described as a plane housing, but, in another embodiment, the housing may be configured so as to have a curvature, thereby imparting to the assembled cooling circuit a geometric shape which approximates a circle. The angle between the channels 10 and the pipe openings 8, 9 is changed hereby from being essentially perpendicular to an angle which is greater than ninety degrees, but smaller than one hundred and twenty degrees.

The location of the pipe openings 8, 9 on the lower side of the base part allows manufacture of the pipes for the cooling circuit in a simple and inex- pensive manner, as the pipes merely have to be cut and deburred and then bent into U-shape.

Relative to the prior art, only one length of pipe is to be used for forming the circuit. In the prior art, three lengths of pipe are used, just as four hermetic soldehngs are to be carried out to establish the circuit, which is twice as many as in the invention.

Moreover, the selected configuration of the pump housing means that the pump housing has a size which at least corresponds to the spacing be- tween associated inlet and outlet openings, thereby proportionally increasing the resistance in the bottom and the walls of the housing from the electrodes and out to the pipe inlet and pipe outlet, such that the flow will run through the circulating liquid between the electrodes to a greater degree.

The cooling circuit is normally powered from the power supply to the electronic components which are to be cooled. Therefore, it is desirable to reduce the power load originating from the cooling circuit as much as possible.

The pump housing 1 may be made of stainless steel. The housing is constructed by milling on a machine tool and may be made with fine tolerances. This manufacturing method is expensive and not very expedient for real batch production of the housing.

However, the housing may also be injection-moulded in stainless steel by means of the known MIM (metal injection moulding) process, so that it is possible to manufacture greater batches of the pump housing, while reducing the employed amount of material significantly.

The housing may also be made of a suitable sintered metal. Sintering is a suitable process for the manufacture of the housing in large numbers.

In addition, the housing may be made of pressed metal sheeting, where the base part and the lid part of the housing are pressed as two halves, which are joined subsequently by suitable methods.

The joint between the base part and the lid part of the pump housing and between the pump housing and the U-pipes must be carried out hermetically. A plurality of suitable joining methods are available for this, it being advantageously possible to use soldering materials having a higher melting point than the melting point of the cooling fins on the heat exchanger, which cooling fins will primarily be made of an aluminium alloy. Such an advantageous soldering material is silver.

An alternative soldering material having a melting point lower than the melting point of the cooling fins on the heat exchanger may be used on all solder joints, whereby all solderings on the entire cooling circuit may be made in one heating at the same time.

Suitable joining methods are inter alia induction soldering or resistance sol- dering.

In induction soldering, the solder point is subjected to a high frequency signal, whereby the solder point is heated strongly, such that a solder brick of e.g. silver solder arranged on the solder point melts and adheres to the faces on the solder point. In resistance soldering, electrodes are arranged on their respective sides of the solder point, and a current is passed through the area, heating the solder point strongly so that a solder brick of e.g. silver solder melts and adheres to the faces on the solder point.

A combination of soft soldering and hard soldering, where the joints between cooling plate and U-pipes and between heat exchanger and U-pipes are carried out as a soft soldering at a low temperature, and where the joint between the housing and the U-pipes is carried out e.g. by induction sol- dering, where the heat is supplied locally, provides the possibility of locally using soldering materials having a high strength, density and melting temperature.

But other methods, e.g. gluing techniques which use heat conductive glue, and which are capable of establishing a hermetic joint, may also be put to use.

A method of assembling a cooling circuit having an electromagnetic pump comprising a pump housing as described above, will therefore include:

- that the pipes 3 are cut to the desired length and are bent into U-shape,

- that the cooling plate 5 and the heat exchanger 4 are mounted on the pipes 3 to an assembled unit, and

- that the pump housing 1 is mounted on the pipe ends 16 of the unit.

The components are then joined by a relevant joining method.

Claims

PATENT CLAIMS

1. A pump housing (1) for an electromagnetic pump (2) for the propulsion of a conductive liquid in pipes (3), in particular for the cooling of electric components, wherein the pump housing, together with the pipes, forms a closed circuit with which a heat exchanger (4) and a cooling plate (5) are connected, and wherein the pump housing comprises a base part (6) and a lid part (7), and the base part additionally comprises at least two pipe inlet openings (8) and at least two pipe outlet openings (9) arranged at opposed ends of the base part, and wherein the interior of the base part is divided into a plurality of channels (10) of inwardly protruding barriers (11), and each channel extends between a pipe inlet opening and a pipe outlet opening, and the barriers extend between the channels from the two ends of the base part, where the pipe openings (8, 9) are arranged, and inwards toward the centre of the base part, wherein two electrodes (12, 13) are arranged on opposed sides of the base part perpendicularly to the channels, characterized in that the pipe inlet openings (8) and the pipe outlet openings (9) of the housing (1) are provided on the lower side (14) of the base part (6) and point at an essentially right angle into the channels (10) in the interior of the base part, and that the spacing between associated pipe openings (8, 9) corresponds to the spacing between the pipe ends (16) of the pipes (3).

2. A pump housing according to claim 1, characterized in that the angle between the pipe openings (8, 9) and the channels (10) is from ninety to one hundred and twenty degrees.

3. A pump housing according to claim 1, characterized in that the lid part (7) is equipped with deflection devices (15) immediately above each pipe opening (8, 9).

4. A pump housing according to claim 1, characterized in that the electrodes (12, 13) are configured as outwardly protruding pins, and that the electrode (13) is configured as a pipe for the filling of cooling liquid.

5. A pump housing according to claim 1, characterized in that the base part and the lid part are provided by milling in stainless steel.

6. A pump housing according to claim ^characterized in that the base part is provided by injection moulding in stainless steel.

7. A pump housing according to claim 1, characterized in that the base part and the lid part are made of sintered metal.

8. A pump housing according to claim ^characterized in that the base part and the lid part are made of pressed metal sheeting.

9. A pump housing according to any one of claims 5-8, characterize d in that the base part and the lid part are joined hermetically by soldering or gluing.

10. A method of joining a cooling circuit with an electromagnetic pump comprising a pump housing according to any one of the preceding claims, characterized in

- that the pipes (3) are cut to the desired length and bent into U-shape,

- that the cooling plate (5) and the heat exchanger (4) are mounted on the pipes (3) to form an assembled unit, and

- that the pump housing (1 ) is mounted on the pipe ends (16) of the unit.

11. A method according to claim 10, characterized in that all contact faces between pipes and cooling plate, pipes and heat exchanger, and between pipe ends and pump housing are silver-soldered.

12. A method according to claim 10, characterized in that all contact faces between pipes and cooling plate and pipes and heat exchanger are soft soldered, and that all contact faces between pipe ends and pump housing are hard soldered.

13. A method according to claim 10, characterized in that all contact faces between pipes and cooling plate, pipes and heat exchanger, and pipe ends and pump housing are joined by a heat conductive and heat resistant glue.