JP7137392B2 - Filters and filter systems - Google Patents

Description

The present invention relates to filters and filter systems for filtering liquefied gases.

2. Description of the Related Art Conventionally, filters are known for filtering fine impurities in gases used in semiconductor manufacturing and the like. In recent years, with the high integration of semiconductors, the filtration accuracy required for filters is increasing year by year. For example, the cylindrical filter body of Patent Document 1 below guarantees the required filtration accuracy by having a second filter layer with fine filtration characteristics.

JP 2014-104462 A

When the gas to be filtered is a liquefied gas that is liquid at normal temperature and normal pressure, the liquefied gas that has been gasified at a high temperature drops in temperature when it passes through the filter and re-liquefies, causing the filter to become clogged. In order to deal with this problem, for example, in Patent Document 1, by heating the housing container, the temperature of the entire cylindrical filter body is raised to prevent reliquefaction.

However, the filtering portion of the cylindrical filter body of Patent Document 1 has a lower thermal conductivity than the housing container, and since the filtering portion is separated from the housing container, the filtering portion cannot be sufficiently heated. I didn't. On the other hand, this cylindrical filter body can heat the filter portion to a desired temperature by heating the housing container to a higher temperature, but in this case, the temperature of the housing container becomes too high, and the liquefied gas is deteriorated. There was fear.

SUMMARY OF THE INVENTION The present invention has been devised in view of the actual situation as described above, and a main object of the present invention is to provide a filter and a filter system capable of continuously filtering liquefied gas without altering its properties.

The present invention is a filter for filtering liquefied gas, comprising a substantially cylindrical housing and a partition member arranged to divide the inside of the housing into an upstream side and a downstream side of the flow of the liquefied gas. The housing includes a gas inlet provided at a first end in the axial direction, a gas outlet provided at a second end in the axial direction, and a heat receiving portion for receiving heat supplied from the outside. , the partition member is arranged coaxially with the housing and has a gas-permeable substantially cylindrical support; a substantially cylindrical porous filter portion defining a flow channel; and a heat conducting member connecting the second end side of the support to the housing and conducting heat from the heat receiving portion to the support. characterized by comprising

In the filter of the present invention, it is preferable that each of the housing, the heat-conducting member and the support has a higher heat conductivity than the porous filter section.

In the filter of the present invention, it is preferable that the partition member is arranged between the gas inlet and the gas outlet in the housing.

In the filter of the present invention, it is preferable that the partition member includes a cap that closes the first end side of the support.

In the filter of the present invention, it is desirable that the porous filter portion is in close contact with the support.

In the filter of the present invention, the porous filter part has a plurality of discontinuous layers, and the plurality of discontinuous layers comprise a radially innermost layer and a radially outermost layer. Preferably, the average porosity of the innermost layer is smaller than the average porosity of the outermost layer.

In the filter of the present invention, it is desirable that the average porosity of the innermost layer is less than 90% and the average porosity of the outermost layer is 90% or more.

In the filter of the present invention, the plurality of discontinuous layers further include an intermediate layer between the innermost layer and the outermost layer, and the average porosity of the intermediate layer is greater than the average porosity of the innermost layer. , is preferably smaller than the average porosity of the outermost layer.

In the filter of the present invention, it is desirable that each of the plurality of discontinuous layers is a sintered metal fiber of long fibers.

In the filter of the present invention, the support is preferably made of a metal plate having a plurality of holes.

The present invention is a filter system for filtering liquefied gas, characterized in that it includes the filter described above and a heater for supplying heat to the housing.

In the filter of the present invention, the partition member is arranged coaxially with the housing and has a gas-permeable substantially cylindrical support, and is arranged around the support and is liquefied between the inner peripheral surface of the housing. a substantially cylindrical porous filter portion that defines a flow path into which gas flows; and a heat conducting member that connects the second end side of the support to the housing and conducts heat from the heat receiving portion to the support. contains.

In such a filter, the housing and the support are uniformly heated via the heat-conducting member, so that the entire filter can be heated without raising the temperature of the housing to excessively high, and the liquefied gas can be reliquefied. can be deterred. In addition, in the filter of the present invention, the flow path and the porous filter section, which have low thermal conductivity, are sandwiched between the housing and the support and heated from both sides in the radial direction. Uniform heating can be achieved, and deterioration of the liquefied gas can be suppressed. Therefore, the filter of the present invention can continuously filter the liquefied gas without altering it.

1 is a cross-sectional view showing one embodiment of a filter of the present invention; FIG. FIG. 2 is a partial end view taken along line AA of FIG. 1; FIG. 4 is an exploded cross-sectional view of the filter; 4 is a flow chart illustrating one embodiment of a method for manufacturing a filter;

An embodiment of the present invention will be described in detail below with reference to the drawings.
FIG. 1 is a cross-sectional view showing a filter 1 of this embodiment. As shown in FIG. 1, the filter 1 of this embodiment is for filtering fine impurities in a liquefied gas G used in semiconductor manufacturing or the like. This filter 1 includes a substantially cylindrical housing 2 and a partition member 3 arranged so as to divide the inside thereof into an upstream side and a downstream side of the flow of the liquefied gas G. As shown in FIG. Here, the liquefied gas G of this embodiment is gasified by heating the liquid to a high temperature state at normal temperature and normal pressure.

The housing 2 includes a gas inlet 4 provided on the first axial end 2a side, a gas outlet 5 provided on the axial second end 2b side, and a heat receiving portion 6 for receiving heat supply from the outside. and should preferably be included. Since the housing 2 is provided with the gas inlet 4 and the gas outlet 5 at both ends in the axial direction, the liquefied gas G flowing from the gas inlet 4 can be uniformly dispersed within the housing 2 . Also, the liquefied gas G in the housing 2 can be uniformly heated by the radiant heat of the housing 2 heated by the heat from the heat receiving portion 6 of the housing 2 .

The partition member 3 of this embodiment includes a substantially cylindrical support 7 arranged coaxially with the housing 2 , a substantially cylindrical porous filter portion 8 arranged around the support 7 , and a heat receiving portion 6 . and a heat conducting member 9 for conducting the heat of the support 7 .

The support 7 desirably has gas permeability. Such a support body 7 can smoothly flow the liquefied gas G that has passed through the porous filter portion 8 arranged around it. Moreover, it is desirable that the inside of the support 7 communicates with the gas outlet 5 . Such a support body 7 can smoothly flow out the liquefied gas G that has passed through the porous filter portion 8 .

The porous filter portion 8 of the present embodiment defines a channel 10 with the inner peripheral surface of the housing 2 into which the liquefied gas G flows. Since such a porous filter portion 8 is arranged around the support 7 arranged coaxially with the housing 2, the distance L1 between the porous filter portion 8 and the inner peripheral surface of the housing 2 in the circumferential direction is can be made uniform. Therefore, the flow path 10 can uniformly disperse the liquefied gas G in the circumferential direction.

The heat conducting member 9 connects the second end 2b side of the support 7 to the housing 2, for example. Such a heat conducting member 9 prevents the liquefied gas G on the upstream side from flowing downstream without passing through the porous filter portion 8, and the liquefied gas G that has passed through the porous filter portion 8 flows backward to the upstream side. can be prevented.

In the filter 1 described above, the housing 2 and the support 7 are evenly heated through the heat conducting member 9, so that the entire filter 1 can be heated without excessively heating the housing 2, resulting in liquefaction. Re-liquefaction of the gas G can be suppressed. In addition, in the filter 1 of the present embodiment, the flow path 10 and the porous filter portion 8 having a low thermal conductivity are sandwiched between the housing 2 and the support 7 and heated from both sides in the radial direction. The quality filter part 8 can be efficiently and uniformly heated, and deterioration of the liquefied gas G can be suppressed. Therefore, the filter 1 of the present embodiment can continuously filter the liquefied gas G without altering its properties.

Next, a filter system 11 including the filter 1 of this embodiment will be described.
A filter system 11 of this embodiment is for filtering fine impurities in a liquefied gas G used in semiconductor manufacturing or the like, and includes a filter 1 and a heater 12 for supplying heat to a housing 2. .

The heater 12 supplies heat to the heat receiving portion 6 provided on the first end 2a side of the housing 2, for example. The heater 12 and the heat-receiving part 6 are not limited to the illustrated positions, and may be provided in other parts as long as they can heat the housing 2 . Such a filter system 11 does not require the heater 12 to be provided in the filter 1, and the optimum arrangement of the filter 1 and the heater 12 can be freely selected. Note that the heater 12 may be, for example, a component of a semiconductor manufacturing apparatus (not shown).

Next, more preferred aspects of each component of the filter 1 will be described.
The housing 2 is made of stainless steel, for example. Such a housing 2 has good thermal conductivity, and can evenly transmit the heat supplied from the heat receiving portion 6 to the entire housing 2 .

Preferably, the housing 2 is provided at the first end 2a and the second end 2b with mounting portions 13 to which a liquefied gas transfer pipe (not shown) of the semiconductor manufacturing apparatus can be connected. The attachment portion 13 has, for example, a screw structure. Such a housing 2 can be easily attached to a semiconductor manufacturing apparatus, and the time required for replacement and maintenance of the filter 1 can be shortened.

The partition member 3 of this embodiment is arranged between the gas inlet 4 and the gas outlet 5 in the housing 2 . Since such a partition member 3 is disposed in the flow of the liquefied gas G flowing from the gas inlet 4 to the gas outlet 5, it is possible to reliably separate the upstream side and the downstream side.

The partition member 3 preferably includes a cap 14 that closes the first end 2a side of the support 7 . Such a cap 14 prevents the liquefied gas G on the upstream side from flowing downstream without passing through the porous filter portion 8, and prevents the liquefied gas G that has passed through the porous filter portion 8 from flowing backward to the upstream side. can be prevented.

The support 7 of this embodiment is made of a metal plate with a plurality of holes 15 formed therein. This metal plate is, for example, a stainless steel punching metal. Such a support 7 has good thermal conductivity, and can evenly conduct the heat supplied from the heat-conducting member 9 to the entire support 7 .

The holes 15 in the support 7 preferably have a diameter of 1.0-1.5 mm. Such a support 7 has sufficient rigidity to hold the porous filter portion 8 and allows the liquefied gas G that has passed through the porous filter portion 8 to flow smoothly inside.

2 is an end view of line AA of FIG. 1. FIG. As shown in FIGS. 1 and 2, the porous filter section 8 of this embodiment is in close contact with the support 7. As shown in FIGS. Such a porous filter portion 8 can efficiently receive heat from the support 7, and the entire porous filter portion 8 can be uniformly heated.

As shown in FIG. 2, porous filter portion 8 preferably has a plurality of discontinuous layers 16 . The plurality of discontinuous layers 16 are, for example, sintered metal fibers of long fibers each having a space inside stainless steel. The average fiber diameter of the long fibers is preferably 1-100 μm. Such a porous filter portion 8 can filter fine impurities in the liquefied gas G with high accuracy.

The plurality of discontinuous layers 16 includes, for example, a radially innermost innermost layer 16A and a radially outermost outermost layer 16B. The average porosity P1 of the innermost layer 16A is preferably smaller than the average porosity P2 of the outermost layer 16B. Such a porous filter portion 8 can reduce the overall radial thickness while exhibiting high filtration accuracy with respect to the liquefied gas G, so that the size of the filter 1 can be reduced.

The average porosity P1 of the innermost layer 16A is preferably less than 90%, more preferably 80% to 89%. The average porosity P2 of the outermost layer 16B is preferably 90% or more, more preferably 90% to 94%. Such a porous filter portion 8 can filter the liquefied gas G smoothly and accurately.

The multiple discontinuous layers 16 of this embodiment further include an intermediate layer 16C between the innermost layer 16A and the outermost layer 16B. The average porosity P3 of the intermediate layer 16C is preferably larger than the average porosity P1 of the innermost layer 16A and smaller than the average porosity P2 of the outermost layer 16B. The average porosity P3 of the intermediate layer 16C is preferably 85% to 92%. Such a porous filter portion 8 has an average porosity P that decreases stepwise from the outermost layer 16B to the innermost layer 16A. It can be filtered smoothly.

Although a case of three layers has been exemplified as the plurality of discontinuous layers 16 described above, the plurality of discontinuous layers 16 is not limited to three layers. The plurality of discontinuous layers 16 may be, for example, four layers or more, or two layers. Even when there are four or more discontinuous layers 16, it is desirable that the average porosity P of the porous filter part 8 gradually decreases from the outermost layer 16B to the innermost layer 16A.

The heat conducting member 9 is made of stainless steel, for example. The heat-conducting member 9 of this embodiment includes a radially protruding flange portion 9a. It is desirable that the outer diameter of the flange portion 9 a is equal to the outer diameter of the housing 2 . Such a heat-conducting member 9 has good heat conductivity and can efficiently conduct heat supplied from the housing 2 to the support 7 . Further, the heat conducting member 9 can be easily positioned with respect to the housing 2, and the highly accurate filter 1 can be manufactured efficiently.

The cap 14 is made of stainless steel, for example. Such a heat conducting member 9 has good heat conductivity and is efficiently heated by the heat supplied from the support 7 . Therefore, the cap 14 is maintained in a high temperature state, and can prevent the liquefied gas G flowing from the gas inlet 4 from coming into contact with the cap 14 and being re-liquefied.

The cap 14 of this embodiment is fixed to the support 7 without contacting the housing 2 . Such a cap 14 can reduce the flow resistance of the liquefied gas G flowing from the gas inlet 4 and suppress the pressure loss of the liquefied gas G.

Note that the cap 14 may be in contact with the housing 2 at a portion thereof, for example. Such a cap 14 can transmit heat supplied from the heat receiving portion 6 of the housing 2 to the support 7, and can heat the support 7 and the porous filter portion 8 more efficiently.

The housing 2 , the thermally conductive member 9 , the support 7 and the cap 14 of this embodiment each have higher thermal conductivity than the porous filter portion 8 . Therefore, the heat supplied from the heat receiving portion 6 of the housing 2 is efficiently transferred to the heat conducting member 9, the support 7 and the cap 14. As shown in FIG. The porous filter section 8 and the flow path 10, which have low thermal conductivity, are uniformly heated by the housing 2, the thermally conductive member 9, the support 7 and the cap 14, and can be maintained at a desired temperature.

In the above embodiment, the housing 2, the support 7, the porous filter portion 8, the heat conducting member 9 and the cap 14 are all made of stainless steel, but these are made of nickel or nickel alloy, for example. may be Such a filter 1 can continuously filter the corrosive liquefied gas G.

Next, a method for manufacturing the filter 1 of this embodiment will be described.
FIG. 3 is an exploded cross-sectional view of the filter 1, and FIG. 4 is a flow chart showing a method for manufacturing the filter 1 of this embodiment. As shown in FIGS. 3 and 4, in the method of manufacturing the filter 1 of the present embodiment, first, a partition member forming step S1 for forming the partition member 3 is performed.

In the partition member forming step S1, for example, as a first step, a plurality of discontinuous layers 16 of the porous filter section 8 are laminated around the supporting member 7 formed by forming a punching metal into a cylindrical shape. The porous filter part 8 is preferably sintered layer by layer in order from the innermost layer 16A. That is, in the plurality of discontinuous layers 16 of the porous filter portion 8 , first, the innermost layer 16A is sintered around the support 7 . A plurality of discontinuous layers 16 are then formed by sintering intermediate layer 16C around innermost layer 16A and then sintering outermost layer 16B around intermediate layer 16C.

In the partition member forming step S1 of the present embodiment, the support 7 on which the discontinuous layer 16 is laminated is welded to the heat conducting member 9 as the second step. In the partition member forming step S1, as the third step, it is desirable to weld the cap 14 to the support 7 on which the plurality of discontinuous layers 16 are laminated. For welding, for example, laser welding can be preferably adopted. Such a partition member forming step S1 can efficiently manufacture a plurality of discontinuous layers 16 with high accuracy. In this embodiment, laser welding is exemplified as welding, but well-known welding such as plasma welding, TIG welding, etc., may be appropriately employed instead of laser welding.

In the manufacturing method of the filter 1 of the present embodiment, the partition member forming step S1 is followed by the housing member forming step S2 in which the housing 2 is formed as three members: the gas inlet portion 2A, the gas outlet portion 2B, and the cylindrical portion 2C. is done. The housing member forming step S2 need not be performed after the partition member forming step S1, and may be performed in a separate step from the partition member forming step S1, for example.

In the manufacturing method of the filter 1 of the present embodiment, the housing member forming step S2 is followed by the first welding step S3 in which the gas inlet portion 2A and the cylindrical portion 2C are welded together. For the first welding step S3, laser welding, for example, can be suitably adopted, like the welding in the partition member forming step S1.

In the method for manufacturing the filter 1 of the present embodiment, after the first welding step S3, the partition member 3 formed in the partition member forming step S1 is inserted from the gas outlet portion 2B side of the cylindrical portion 2C that has not yet been welded. The assembling step S4 is performed. In the assembling step S4, it is desirable that the flange 9a of the heat conducting member 9 is positioned in contact with the cylindrical portion 2C. Further, in the assembling step S4 of the present embodiment, it is desirable that the flange 9a of the heat conducting member 9 is brought into contact with the gas outlet portion 2B. Such an assembling step S4 facilitates the positioning of the heat conducting member 9 and the housing 2, and can efficiently manufacture the high-precision filter 1. As shown in FIG.

In the manufacturing method of the filter 1 of the present embodiment, the assembling step S4 is followed by the second welding step S5 in which the cylindrical portion 2C, the partition member 3 and the gas outlet portion 2B are welded. Laser welding, for example, can be suitably employed in the second welding step S5, as in the welding of the partition member forming step S1 and the first welding step S3. Such a method for manufacturing the filter 1 can easily manufacture the filter 1 that can stably exhibit good filtration accuracy. In the first welding step S3 and the second welding step S5, similar to the welding in the partition member forming step S1, well-known methods such as plasma welding and TIG welding may be appropriately employed in place of laser welding.

Although the particularly preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments and can be modified in various ways.

REFERENCE SIGNS LIST 1 filter 2 housing 3 partition member 4 gas inlet 5 gas outlet 6 heat receiving section 7 support 8 porous filter section 9 heat conducting member 10 flow path

Claims (10)

A filter for filtering a liquefied gas, comprising:
A substantially cylindrical housing, and a partition member arranged to divide the interior into an upstream side and a downstream side of the flow of the liquefied gas,
The housing includes a gas inlet provided at a first end in the axial direction, a gas outlet provided at a second end in the axial direction, and a heat receiving portion for receiving heat supplied from the outside,
The partition member
a substantially cylindrical support disposed coaxially with the housing and having gas permeability;
a substantially cylindrical porous filter portion arranged around the support and defining a flow path through which the liquefied gas flows between the support and the inner peripheral surface of the housing;
a heat conducting member for connecting the second end side of the support to the housing and transmitting heat from the heat receiving portion to the support ;
a cap that closes the first end side of the support,
the housing, the thermally conductive member, the support and the cap each have a higher thermal conductivity than the porous filter section ;
the cap is secured to the support;
The flow path and the porous filter section are sandwiched between the housing and the support ,
filter. 2. The filter of claim 1 , wherein said cap does not contact said housing . 3. A filter according to claim 1 or 2, wherein the partition member is arranged between the gas inlet and the gas outlet in the housing. 4. A filter according to any one of claims 1 to 3, wherein the heat conducting member comprises a radially projecting flange portion . 5. The filter according to any one of claims 1 to 4, wherein said porous filter portion is in close contact with said support. The porous filter part has a plurality of discontinuous layers,
The plurality of discontinuous layers includes a radially innermost innermost layer and a radially outermost outermost layer,
6. The filter according to any one of claims 1 to 5, wherein the average porosity of the innermost layer is smaller than the average porosity of the outermost layer. The innermost layer has an average porosity of less than 90%,
7. The filter according to claim 6, wherein said outermost layer has an average porosity of 90% or more. the plurality of discontinuous layers further comprising an intermediate layer between the innermost layer and the outermost layer;
8. The filter according to claim 6 or 7, wherein the average porosity of the intermediate layer is larger than the average porosity of the innermost layer and smaller than the average porosity of the outermost layer. 9. The filter according to any one of claims 1 to 8 , wherein said support is formed from a metal plate with a plurality of holes formed therein. A filter system for filtering the liquefied gas, comprising:
The filter according to any one of claims 1 to 9 and a heater for supplying heat to the housing,
filter system.

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