Cooling Device with a Filter Unit

Abstract

The invention relates to a cooling device comprising a cooling unit (10) that is penetrated by a fluid to be cooled, in particular hydraulic oil, and a filter unit (12) for filtering said fluid, the filter unit (12) extending along a longitudinal side of the cooling unit (10) and a fluid collecting space (16) being arranged between the filter unit (12) and the cooling unit (10). The invention is characterized in that the fluid collecting space (16) has a uniform flow cross-section and is at least partially closed against the filter unit (12) by a concavely curved limitating wall (36). The optimized fluid guidance obtained thereby results in a uniformisation of speed while at the same time avoiding cavities and turbulences in order to ensure a trouble-free and energetically favorable operation of the inventive cooling device.

Description

The invention relates to a cooling device with a cooling unit through which a fluid to be cooled, in particular hydraulic oil, can flow, and with a filter unit for filtration of the fluid, the filter unit extending on one longitudinal side of the cooling unit and a fluid collecting chamber being located between the filter unit and the cooling unit.

These cooling devices (U.S. Pat. No. 4,295,964, CH 533 246 A) can be used for a host of applications and are available in the most varied embodiments. The cooling device systems which have been readily available on the market to date, however, all consist predominantly of a filter unit which is flanged to the cooling unit, or of tank units which are connected to the cooling units, the respective tank unit then holding the filter element. The known cooling devices are therefore generally composed of several components, and the independent cooling unit can be connected by way of the corresponding piping to the independent filter unit as the cooling device is being produced. As a result of the indicated piping, in the transport of the fluid, flow-induced losses occur; this does not favor energy-efficient operation of the known cooling device. Nor can it be precluded that leaks may occur in the area of the piping. This adversely affects operating reliability.

DE 196 35 777 A discloses a cooling device with a cooling unit through which a fluid to be cooled can flow and with a filter unit for filtration of the fluid, the cooling unit and the filter unit being integrally connected to one another and the filter unit together with the cooling unit being located in a device housing. This document also discloses using a plate-shaped finned radiator as the cooling unit and the filter element is held in a filter housing in the known solution such that it is an integral component of the device housing.

U.S. Pat. No. 5,159,821 moreover discloses a cooling device with a filter disk with a small structure in the axial direction as the filter element which, located in the device housing, also holds a plate-shaped finned radiator as the cooling unit. A drying medium extends in the fluid direction in front of the filter element within the device housing, the filter element disk which is connected upstream of the finned radiator on one of its longitudinal sides occupying only a small overall length there. In these known solutions as well, flow losses occur in the operation of the filter device; this can lead to low filter efficiency. To some extent, a used filter element can be replaced by a new element only with great difficultly.

EP 1 261 809 B1 discloses a generic cooling device with a cooling unit through which a fluid to be cooled, especially hydraulic oil, can flow, and with a filter unit for filtration of the fluid, the cooling unit and the filter unit being integrally connected to one another, which together with the cooling unit is located in a device housing, the cooling unit as a plate-shaped finned radiator assuming the incipient cooling tasks. The filter unit is located in the flow direction of the fluid to be cooled upstream from the plate-shaped finned radiator; this has the advantage that potential fouling, when filtered out of the fluid flow, cannot adversely affect reliable operation of the cooling unit. In the known solution the filter unit extends essentially along one longitudinal side of the finned radiator, between the filter unit and the cooling unit a fluid collecting chamber being connected. This fluid collecting chamber has different cross sectional areas, in particular, the cross section widens in the direction of the bottom side of the cooling device so that unfavorable flow conditions can occur with cavity formation; this is disadvantageous for undisrupted, energy-saving operation of the known cooling device and it has been found in particular that at very low flow velocities of the fluid the distribution of the latter out of the fluid collecting chamber to the cooling unit leads to nonuniform distribution situations. This adversely affects effective cooling of the fluid. In addition, the known solution is expensive and complex to produce.

Proceeding from this prior art, the object of this invention is to further improve the known cooling devices such that they enable altogether improved operation, especially also at low flow velocities. This object is achieved by a cooling device with the features of claim 1 in its entirety.

In that, as specified in the characterizing part of claim 1, the fluid collecting chamber has a uniform flow cross section and is sealed relative to the filter unit at least partially by a concavely curved boundary wall, optimized fluid routing is achieved which leads to the velocity behavior becoming uniform while avoiding cavities and turbulence so that in this respect trouble-free, energy-efficient operation is possible with the cooling device according to the invention.

In particular, the free fluid cross section in the fluid collecting chamber can be adapted to the free flow cross sections in the area of the filter unit, its preferably being provided that the fluid collecting chamber is made semicircular in cross section, the filter unit having a filter element which is held in a filter housing with a cylindrical installation space. Thus, the free flow cross sections can continue and remain within the filter housing in the fluid collecting chamber so that in spite of deflected flows in the area of the transition between the filter housing and the fluid collecting chamber, for the most part problem-free fluid transport is achieved.

In one especially preferred embodiment of the cooling device according to the invention, it is provided that the fluid collecting chamber in the middle has another boundary wall which divides the fluid collecting chamber into two component spaces, of which one has a fluid connection to the filter housing and the other has an outlet for discharge of filtered and cooled fluid. As a result of the other boundary wall in the fluid collecting chamber the fluid flow can be divided, one component flow coming from the filter unit first being supplied to the part of the cooling unit, which flow, in the reverse direction and cooled by the other part of the cooling unit, re-enters the component space of the fluid collecting chamber bordered by the other boundary wall, in order from there to leave the cooling device filtered and cooled. This arrangement is especially favorable for fluid flows to be routed with a low speed. By division and due to separation via the respective boundary wall the cooling and transport performances can be “proportioned”; this cannot be achieved with the known, described solutions.

Other advantageous embodiments of the cooling device according to the invention are the subject matter of the other dependent claims.

The cooling device according to the invention will be detailed below using one embodiment as shown in the drawings. The figures are schematic and not to scale.

FIG. 1 shows the cooling device as a whole, partially in a longitudinal section, partially in a perspective top view;

FIG. 2 shows the structure of the filter housing and fluid collecting chamber located on the left viewed in the direction of looking at FIG. 1, without the filter element inserted.

The cooling device shown in the figures has a cooling unit 10 through which a fluid to be cooled, in particular, hydraulic oil, can flow, and a filter unit 12 for filtration of this fluid. The cooling unit 10 is made as a plate-shaped finned radiator, i.e., to guide the cooling air, the plate radiator has fins (not shown) which are folded up in a zig-zag shape and which between themselves border fluid routing channels 14 which are used to transport the fluid to be cooled. The direction of air routing through the cooling unit 10 runs perpendicular to the plane of FIG. 1 and the fluid transport direction transversely thereto, that is, within the plane of the figure. Furthermore, the stacked fluid routing channels 14 discharge on either side into the fluid collecting chambers 16, 18. The structure of these finned radiators is in general conventional, so that it will no longer be detailed here. The device housing of the cooling unit 10 can consist of an aluminum casting or the like; but it can also be composed in the conventional manner of sheet metal parts in a box shape and can be assembled to form the overall housing via weld connections. For the sake of simplicity, the upper and the lower end wall for the collecting chamber 16 are not shown.

Viewed in the direction of looking at FIG. 1, the filter unit 12 extends on the left longitudinal side of the cooling unit 10 and the filter unit 12 has a filter housing 20 on a cylindrical installation space 22 which lies in the middle for holding a cylindrical filter element 24 of conventional design. This filter unit 24 is made of conventional filtration materials and consists, for example, of a pleated, hollow cylindrical, multilayer filter mat which surrounds a middle support tube which is not detailed. Viewed in the direction of looking at FIG. 1, the filter housing 20 in its upper end area has an inlet 26 for at least partially fouled and heated fluid. The fluid which has been supplied in this way via the inlet 26 flows through the filter element 24 from the outside to the inside and the filtered fluid is discharged in the middle from the filter element 24 through the bottom outlet opening 28 of a spacer layer 30. This spacer layer 30 is supported on a clip-like or cage-like holding unit 32 with individual holding rods 33, which in turn are supported on the bottom part 34 of the filter housing 20. This bottom part 34 can seal the filter unit 12 fluid-tight to the bottom, that is, on the bottom-side, but can also be used to hold a bypass valve which is not detailed in order for example to supply fouled fluid cleaned by the filter unit 12 not to the cooling unit 10 for cooling purposes, but to drain it out of the device; this can be advantageous, for example, when the temperature of the filtered fluid does not yet necessitate cooling or does so only partially.

By means of the holding unit 32 and the spacer layer 30 it is possible to insert filter elements 24, which are different in terms of overall length, into the same cooling device in order to perform various filtration tasks in practical applications. But preferably, as shown in FIG. 1, the overall length of the filter element 24 is chosen such that in the axial direction only roughly half of the installation space 22 of the filter housing 20 is used up so that in this respect underneath the filter element 24 a cylindrical holding space is formed which also contributes to making the fluid flow uniform in the filter housing 20 after filtration.

As FIG. 1 furthermore shows, between the filter unit 12 and the cooling unit 10 is the first fluid collecting chamber 26 with an axial extension length which is adapted according to connection possibilities on the longitudinal side of the finned radiator as the cooling unit 10. This fluid collecting chamber 16 has a uniform flow cross section and is closed by a concavely curved boundary wall 36 relative to the filter unit 12. These conditions are especially clearly illustrated in FIG. 2. In this way, for the fluid collecting chamber 26 a type of semicircular tube is formed which with its flat connection cross section engages the face of the finned radiator.

Preferably the other or the second fluid collecting chamber 18 on the opposite longitudinal side of the finned radiator has a comparable half tube structure; here, however, the possibility also exists of selecting a different, in particular, square cross section. Furthermore, it is provided that the fluid collecting chamber 18 continuously has connection possibilities to the fluid routing channels 14 of the cooling unit 10. In the embodiment shown in the figures, the fluid collecting chamber 16 is divided roughly in the middle by another boundary wall 38 which divides the fluid collecting chamber 16 fluid-tight into two component spaces 40, 42.

To supply the lower component space 40, a transverse passage site 44 is used, preferably in the form of a hole which connects the component space 40 to carry fluid to the interior of the filter housing 20, in particular to the installation space 22 for the filter element 24. Fluid which has been filtered in this way is thus fed into the component space 40 by way of the transverse passage site 44 and then flows from left to right through the fluid routing channels 14, cooling being induced by the cooling unit 10 in its lower half area. The fluid or medium which has been cooled in this way then enters the other fluid collecting chamber 18, rises toward the top when viewed in the direction of looking at FIG. 1, and then crosses the fluid routing channels 14 from right to left in the upper area, in particular in the upper half of the cooling unit 10. The fluid medium which has then been completely cooled in this way enters the second or upper component space 42 and from there the fluid which has been filtered and cooled leaves the fluid device via the outlet 46 which has the same axial direction as the inlet 26 (compare the partial representation as shown in FIG. 2).

The arrangement described in this way for the most part makes the fluid flow uniform both in the filter unit 12 and also in the cooling unit 10 and in the two fluid collecting chambers 16, 18. In particular, slowly flowing fluid can be filtered and cooled in this way without disruption, and due to the constantly maintained cross sectional characteristics energy-efficient filtering and cooling operation with the cooling device according to the invention are possible. As FIG. 2 shows in particular, the filter unit 12 with the fluid collecting chamber 16 can be produced in one piece, for example in the form of a diecasting, in order to connect the unit which has then been produced in this way fluid-tight to the remaining cooling unit 10 on its one face side by means of a conventional welding process. If the other boundary wall 38 is omitted, with the described cooling device according to the invention, even more quickly flowing media can be reliably managed, then preferably in the area of the second fluid collecting chamber 18 an outlet (not shown) having to be provided for discharging the filtered and cooled fluid. With the cooling device according to the invention a unit of very compact structure is formed which can be flexibly adapted to the different filtering and cooling tasks without the fundamental structure of the cooling device having to be changed; this helps to save money. Otherwise the cooling device according to the invention is easy to maintain and install; this in turn helps to save money.

Claims

1. A cooling device with a cooling unit (10) through which a fluid to be cooled, especially hydraulic oil, can flow, and with a filter unit (12) for filtration of the fluid, the filter unit (12) extending on one longitudinal side of the cooling unit (10) and a fluid collecting chamber (16) being located between the filter unit (12) and the cooling unit (10), characterized in that the fluid collecting chamber (16) has a uniform flow cross section and is sealed relative to the filter unit (12) at least partially by a concavely curved boundary wall (36).

2. The cooling device according to claim 1, wherein the fluid collecting chamber (16) is made semicircular in cross section and wherein the filter unit (12) has a filter element (24) which is held in a filter housing (20) with a cylindrical installation space (22).

3. The cooling device according to claim 2, wherein the fluid collecting chamber (16) in the middle has another boundary wall (38) which divides the fluid collecting chamber (16) into two component spaces (40, 42), of which one (40) has a fluid connection (44) to the filter housing (20) and the other (42) has an outlet (26) for the discharge of filtered and cooled fluid.

4. The cooling device according to claim 3, wherein the overall length of the filter element (24) in the filter housing (20) corresponds roughly to the distance of the other boundary wall (38) of the two component spaces (40, 42) from their ends.

5. The cooling device according to claim 1, wherein there is another fluid collecting chamber (18) on the longitudinal side of the cooling unit (10) opposite the filter unit (12).

6. The cooling device according to claim 1, wherein the filter housing (20) together with the fluid collecting chamber (16) forms a one-piece unit which can be connected to the cooling unit (10) as another unit.

7. The cooling device according to claim 2, wherein the filter element (24) is supported within the filter housing (20) on a spacer layer (30) which is held by a holding unit (32) which is in turn supported on the bottom part (34) of the filter housing (20).