JP2020018981A - Filter and filter system - Google Patents

Abstract

To provide a filter which can filter liquefied gas continuously without altering the liquefied gas, and to provide a filter system.SOLUTION: A filter 1 is used to filter liquefied gas G and includes; a housing 2 having a substantially cylindrical shape; and a partition member 3 which is disposed so as to partition an interior of the housing 2 into an upstream side of flow of the liquefied gas G and a downstream side. The housing 2 includes: a gas inlet 4 provided at a first end 2a side in an axial direction; a gas outlet 5 provided at a second end 2b side in the axial direction; and a heat reception part 6 for receiving heat supply from the outside. The partition member 3 includes: a support medium 7 which is disposed coaxially with the housing 2, has gas permeability, and has a substantially cylindrical shape; a porous filter part 8 which is disposed around the support medium 7, defines a passage 10, into which the liquefied gas G flows, with an inner peripheral surface of the housing 2, and has a substantially cylindrical shape; and a heat conduction member 9 which connects a second end 2b side of the support medium 7 with the housing 2 and is used to transmit heat from the heat reception part 6 to the support medium 7.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a filter and a filter system for filtering a liquefied gas.

  2. Description of the Related Art Conventionally, a filter for filtering fine impurities of a gas used in semiconductor manufacturing or the like has been known. In recent years, as semiconductors become more highly integrated, the filtering accuracy required for filters has been increasing year by year. For example, the cylindrical filter of Patent Document 1 below has a second filtration layer having fine filtration characteristics, thereby guaranteeing the required filtration accuracy.

JP 2014-104462 A

  When the gas to be filtered is a liquefied gas that is liquid at normal temperature and normal pressure, there is a problem that when the liquefied gas gasified in a high temperature state passes through the filter, the temperature drops, and the gas is reliquefied and the filter is clogged. In order to cope with this problem, for example, in Patent Literature 1, it is conceivable to heat the housing container to raise the temperature of the entire cylindrical filter to prevent re-liquefaction.

  However, the filtration unit of the tubular filtration body of Patent Document 1 has a smaller thermal conductivity than the housing container, and since the filtration unit is separated from the housing container, the filtration unit can be sufficiently heated. Did not. On the other hand, although this cylindrical filter can heat the filtration unit to a desired temperature by heating the housing container to a higher temperature, in this case, the temperature of the housing container becomes too high, and the liquefied gas deteriorates. There was a fear.

  The present invention has been devised in view of the above situation, and has as its main object to provide a filter and a filter system capable of continuously filtering a liquefied gas without deteriorating.

  The present invention is a filter for filtering a liquefied gas, comprising a substantially cylindrical housing and a partition member arranged to divide the inside into an upstream side and a downstream side of the flow of the liquefied gas. The housing includes a gas inlet provided on a first end side in the axial direction, a gas outlet provided on a second end side in the axial direction, and a heat receiving portion for receiving external heat supply. The partition member is disposed coaxially with the housing and has a substantially cylindrical support having gas permeability, and the liquefied gas is disposed around the support and the inner peripheral surface of the housing. A substantially cylindrical porous filter portion that defines a flow channel to flow into, and 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. It is characterized by including.

  In the filter according to the aspect of the invention, it is preferable that the housing, the heat conductive member, and the support have higher thermal conductivity than the porous filter portion.

  In the filter according to the aspect of the invention, it is preferable that the partition member is disposed between the gas inlet and the gas outlet in the housing.

  In the filter according to the aspect of the 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 preferable that the porous filter portion is in close contact with the support.

  In the filter of the present invention, the porous filter portion includes a plurality of discontinuous layers, and the plurality of discontinuous layers include a radially innermost innermost layer and a radially outermost 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, the average porosity of the innermost layer is preferably less than 90%, and the average porosity of the outermost layer is preferably 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 larger than the average porosity of the innermost layer. It is desirable that the average porosity of the outermost layer be smaller than the average porosity.

  In the filter according to the aspect of the invention, it is preferable that each of the plurality of discontinuous layers is a long-fiber metal fiber sintered body.

  In the filter of the present invention, it is preferable that the support is formed of a metal plate having a plurality of holes.

  The present invention is a filter system for filtering liquefied gas, comprising the above-described filter and a heater for supplying heat to the housing.

  In the filter according to the aspect of the invention, the partition member is liquefied between a substantially cylindrical support having gas permeability and being disposed coaxially with the housing, and being disposed around the support and having an inner peripheral surface of the housing. A substantially cylindrical porous filter portion defining a flow path into which gas flows, and a heat conducting member for connecting a second end side of the support to the housing and transmitting heat from a heat receiving portion to the support. Contains.

  In such a filter, since the housing and the support are uniformly heated through the heat conducting member, the entire filter can be heated without excessively high temperature of the housing, and the liquefied gas can be reliquefied. Can be deterred. Further, the filter of the present invention heats the flow path and the porous filter portion having a small thermal conductivity from both sides in the radial direction with the housing and the support sandwiching the flow path and the porous filter portion. Heating can be performed uniformly, and deterioration of the liquefied gas can be suppressed. For this reason, the filter of the present invention can continuously filter the liquefied gas without altering the quality.

It is sectional drawing which shows one Embodiment of the filter of this invention. FIG. 2 is a partial end view taken along line AA of FIG. 1. It is an expanded sectional view of a filter. 6 is a flowchart illustrating an embodiment of a method for manufacturing a filter.

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

  The housing 2 includes a gas inlet 4 provided on the first end 2a side in the axial direction, a gas outlet 5 provided on the second end 2b side in the axial direction, and a heat receiving portion 6 for receiving external heat supply. It is desirable to include In such a housing 2, the gas inlet 4 and the gas outlet 5 are provided at both ends in the axial direction, so that the liquefied gas G flowing from the gas inlet 4 can be uniformly dispersed in the housing 2. Further, the liquefied gas G in the housing 2 can be uniformly heated by the radiation heat of the housing 2 heated by the heat from the heat receiving portion 6 of the housing 2.

  The partition member 3 of the present 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 transmitting the heat of the above to the support 7.

  The support 7 desirably has gas permeability. Such a support 7 can smoothly flow the liquefied gas G that has passed through the porous filter portion 8 disposed around the support 7 to the inside. It is desirable that the inside of the support 7 communicates with the gas outlet 5. Such a support 7 allows the liquefied gas G that has passed through the porous filter portion 8 to flow out smoothly.

  The porous filter section 8 of the present embodiment defines a flow path 10 into which the liquefied gas G flows between the porous filter section 8 and the inner peripheral surface of the housing 2. 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 is set in the circumferential direction. It can be uniform. Therefore, the flow path 10 can uniformly disperse the liquefied gas G in the circumferential direction.

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

  In the above-described filter 1, since the housing 2 and the support 7 are uniformly heated through the heat conducting member 9, the entire filter 1 can be heated without excessively increasing the temperature of the housing 2, and the liquefaction can be performed. Reliquefaction of the gas G can be suppressed. Further, the filter 1 of the present embodiment heats the flow path 10 and the porous filter portion 8 having a small thermal conductivity from both sides in the radial direction with the housing 2 and the support 7 interposed therebetween. The quality filter unit 8 can be efficiently and uniformly heated, and the deterioration of the liquefied gas G can be suppressed. For this reason, the filter 1 of the present embodiment can continuously filter the liquefied gas G without deteriorating.

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

  The heater 12 supplies, for example, heat to the heat receiving unit 6 provided on the first end 2 a side of the housing 2. The heater 12 and the heat receiving section 6 are not limited to the illustrated positions, and may be provided in other portions as long as the housing 2 can be heated. In such a filter system 11, it is not necessary to provide the heater 12 in the filter 1, and the optimal arrangement of the filter 1 and the heater 12 can be freely selected. The heater 12 may be a component of a semiconductor manufacturing apparatus (not shown), for example.

Next, a more preferable embodiment of each component of the filter 1 will be described.
The housing 2 is formed of, for example, stainless steel. Such a housing 2 has good thermal conductivity, and can uniformly transmit the heat supplied from the heat receiving unit 6 to the entire housing 2.

  The housing 2 is preferably provided with a mounting portion 13 at each of the first end 2a and the second end 2b, to which a liquefied gas transport 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 reduced.

  The partition member 3 of the present 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 can be reliably divided into an upstream side and a downstream side.

  The partition member 3 desirably includes a cap 14 for closing the first end 2a side of the support 7. Such a cap 14 allows the liquefied gas G on the upstream side to flow downstream without passing through the porous filter portion 8 and the liquefied gas G passing through the porous filter portion 8 to flow back to the upstream side. Can be prevented.

  The support 7 of the present embodiment is formed from a metal plate on which a plurality of holes 15 are formed. This metal plate is, for example, stainless steel punched metal. Such a support 7 has good thermal conductivity, and can uniformly transmit the heat supplied from the heat conductive member 9 to the entire support 7.

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

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

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

  The plurality of discontinuous layers 16 include, 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 thickness in the radial direction while exhibiting high filtration accuracy for the liquefied gas G, and can reduce the size of the filter 1.

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

  The plurality of discontinuous layers 16 of the present embodiment further include an intermediate layer 16C between the innermost layer 16A and the outermost layer 16B. It is desirable that the average porosity P3 of the intermediate layer 16C is 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%. In such a porous filter portion 8, the average porosity P is gradually reduced from the outermost layer 16B to the innermost layer 16A, and the liquefied gas G is more efficiently filtered while exhibiting high filtration accuracy for the liquefied gas G. It can be filtered smoothly.

  In the above-described plurality of discontinuous layers 16, the case of three layers has been illustrated, but the plurality of discontinuous layers 16 is not limited to three layers. The plurality of discontinuous layers 16 may be, for example, four or more layers or two layers. Even when the number of the discontinuous layers 16 is four or more, it is preferable that the average porosity P of the porous filter portion 8 gradually decreases from the outermost layer 16B to the innermost layer 16A.

  The heat conduction member 9 is formed of, for example, stainless steel. The heat conducting member 9 of the present embodiment includes a flange portion 9a that protrudes in the radial direction. It is desirable that the outer diameter of the flange portion 9 a be equal to the outer diameter of the housing 2. Such a heat conducting member 9 has a good heat conductivity, and can efficiently transmit the heat supplied from the housing 2 to the support 7. Further, the positioning of the heat conductive member 9 with respect to the housing 2 is easy, and the highly accurate filter 1 can be manufactured efficiently.

  The cap 14 is formed of, for example, stainless steel. Such a heat conductive member 9 has a good heat conductivity and is efficiently heated by the heat supplied from the support 7. For this reason, the high temperature state of the cap 14 is maintained, and the liquefied gas G flowing from the gas inlet 4 can be prevented from contacting the cap 14 and being reliquefied.

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

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

  The housing 2, the heat conducting member 9, the support 7, and the cap 14 of the present embodiment each have a higher heat conductivity than the porous filter portion 8. For this reason, the heat supplied from the heat receiving portion 6 of the housing 2 is efficiently transmitted to the heat conducting member 9, the support 7, and the cap 14. Then, the porous filter portion 8 and the flow path 10 having a small thermal conductivity are uniformly heated from the housing 2, the heat conductive member 9, the support 7 and the cap 14, so that a desired temperature can be maintained.

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

Next, a method for manufacturing the filter 1 of the present embodiment will be described.
FIG. 3 is a developed cross-sectional view of the filter 1, and FIG. 4 is a flowchart showing a method of manufacturing the filter 1 of the present 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 stage, a plurality of discontinuous layers 16 of the porous filter portion 8 are stacked around a support 7 in which a punching metal is formed in a cylindrical shape. It is desirable that the porous filter section 8 be sintered one layer at a time 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. The plurality of discontinuous layers 16 are formed by then sintering the middle layer 16C around the innermost layer 16A and then sintering the outermost layer 16B around the middle layer 16C.

  In the partition member forming step S1 of the present embodiment, as a second stage, the support 7 on which the discontinuous layer 16 is laminated is welded to the heat conducting member 9. In the partition member forming step S1, as a third step, it is desirable that the cap 14 is welded to the support 7 on which the plurality of discontinuous layers 16 are stacked. As the welding, for example, laser welding can be suitably adopted. In such a partition member forming step S1, the plurality of discontinuous layers 16 can be manufactured accurately and efficiently. In this embodiment, laser welding is exemplified as welding, but for welding, well-known welding, such as plasma welding or TIG welding, may be appropriately employed instead of laser welding.

  In the manufacturing method of the filter 1 of the present embodiment, the housing member forming step S2 in which the housing 2 is formed as three members of the gas inlet part 2A, the gas outlet part 2B, and the cylindrical part 2C after the partition member forming step S1. Is performed. The housing member forming step S2 does not need to be performed next to the partition member forming step S1, and may be performed in a step different from the partition member forming step S1, for example.

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

  In the method of manufacturing the filter 1 according to the present embodiment, the partition member 3 formed in the partition member forming step S1 is inserted from the unwelded gas outlet 2B side of the cylindrical portion 2C after the first welding step S3. The assembling step S4 is performed. In the assembling step S4, it is desirable that the flange 9a of the heat conduction member 9 be positioned in contact with the cylindrical portion 2C. In the assembling step S <b> 4 of the present embodiment, it is desirable that the gas outlet portion 2 </ b> B be further in contact with the flange 9 a of the heat conducting member 9. In such an assembling step S4, the positioning of the heat conductive member 9 and the housing 2 is easy, and the high-precision filter 1 can be efficiently manufactured.

  In the method for manufacturing the filter 1 according to the present embodiment, a second welding step S5 in which the cylindrical portion 2C, the partition member 3, and the gas outlet 2B are welded is performed after the assembling step S4. In the second welding step S5, for example, laser welding can be suitably adopted, similarly to the welding of the partition member forming step S1 and the first welding step S3. According to such a method for manufacturing the filter 1, the filter 1 that can stably exhibit good filtration accuracy can be easily manufactured. In the first welding step S3 and the second welding step S5, similarly to the welding in the partition member forming step S1, instead of laser welding, for example, well-known methods such as plasma welding and TIG welding may be appropriately used.

  As described above, particularly preferred embodiments of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments, and can be implemented in various modes.

DESCRIPTION OF SYMBOLS 1 Filter 2 Housing 3 Partition member 4 Gas inlet 5 Gas outlet 6 Heat receiving part 7 Supporting body 8 Porous filter part 9 Heat conduction member 10 Flow path

Claims (11)

A filter for filtering liquefied gas,
Including a substantially cylindrical housing, and a partition member arranged to partition the inside into an upstream side and a downstream side of the flow of the liquefied gas,
The housing includes a gas inlet provided on a first end side in the axial direction, a gas outlet provided on a second end side in the axial direction, and a heat receiving unit for receiving heat supply from the outside,
The partition member,
A substantially cylindrical support having a gas permeability and disposed coaxially with the housing;
A substantially cylindrical porous filter portion which is arranged around the support and defines a flow path through which the liquefied gas flows between 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.
filter.   The filter according to claim 1, wherein the housing, the heat conductive member, and the support each have a higher thermal conductivity than the porous filter portion.   The filter according to claim 1, wherein the partition member is disposed between the gas inlet and the gas outlet in the housing.     The filter according to claim 1, wherein the partition member includes a cap that closes the first end side of the support.   The filter according to claim 1, wherein the porous filter portion is in close contact with the support. The porous filter unit has a plurality of discontinuous layers,
The plurality of discontinuous layers include a radially innermost innermost layer and a radially outermost outermost layer,
The filter according to claim 1, wherein an average porosity of the innermost layer is smaller than an average porosity of the outermost layer. The average porosity of the innermost layer is less than 90%;
The filter according to claim 6, wherein the average porosity of the outermost layer is 90% or more. The plurality of discontinuous layers further include an intermediate layer between the innermost layer and the outermost layer,
The filter according to claim 6, 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.   The filter according to any one of claims 6 to 8, wherein each of the plurality of discontinuous layers is a long fiber metal fiber sintered body.   The filter according to any one of claims 1 to 9, wherein the support is formed from a metal plate having a plurality of holes. A filter system for filtering the liquefied gas,
A filter according to any one of claims 1 to 10, and a heater for supplying heat to the housing.
Filter system.

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