This is a National Phase Application in the United States of International Patent Application No. PCT/JP2006/309368 filed May 10, 2006, which claims priority on Japanese Patent Application No. 2005-245804, filed Aug. 26, 2005. The entire disclosures of the above patent applications are hereby incorporated by reference.
The present invention relates to improvements in a gasket type orifice and a pressure type flow rate control apparatus in which the orifice is employed. The present invention relates more specifically to a gasket type orifice having a high precision hole diameter for which a thin metal plate is used so that it can be manufactured at low cost, with high efficiency and also with stability; and to a pressure type flow rate control apparatus in which the gasket type orifice is employed; and to an orifice-replaceable pressure type flow rate control apparatus in which an orifice can be replaced leak-free and promptly, a flow rate range of the pressure type flow rate control apparatus can be changed easily after its field installation, and wherein the flow rate control can be maintained with high accuracy within ±1% FS (Full Scale).
Conventionally, to make an orifice it has been commonly known that an orifice hole is made directly on an orifice plate by means of mechanical processing and the like, wherein the orifice plate is interposed in a pipe passage at an appropriate position on the joint portion of the pipe passage or the connecting portion of a device and a pipe passage, and the orifice plate is directly clamped and fixed hermetically in place. However, with the afore-mentioned orifice of the directly clamped fixing type there is potential for deformation to be caused on the orifice plate due to clamping and fixing of the plate, thus making it difficult to make an orifice plate that is advantageously thin. For this reason, it is difficult to manufacture a high precision orifice having a prescribed hole diameter and shape, without uneven flow rate characteristics, and with stability and at low cost when a thin orifice plate is used.
To solve the afore-mentioned difficulties, an orifice has been developed wherein an orifice plate is welded to appropriate holding hardware, and the orifice plate welded to holding hardware is inserted into a pipe passage and fixed therein. However, with this solution there have arisen certain shortcomings such as that the orifice hole diameter may be altered by influence of heat caused at the time of welding, thermal stress might cause cracks on the thin orifice plate, and, furthermore, corrosion resistance of the orifice plate is low.
As seen above, an orifice, particularly a high precision orifice having certain constraints as to shape, hole diameter, and the like, which is employed with a pressure type flow rate control apparatus and the like cannot be manufactured at low cost, and at the same time it has been found that it is structurally difficult to insert and fix the orifice assembly in a pipe passage, thus causing various problems in practical use.
On the other hand, a pressure type flow rate control apparatus, which includes an orifice as a dispensable constituent member, has excellent characteristics in responsivity, control accuracy, manufacturing cost, maintainability and the like when compared with those same characteristics of a thermal type mass flow rate control apparatus (MFC) represented by a mass flow controller, and such as is widely used in the technical field of semiconductor manufacturing.
a) and
One kind of pressure type flow rate control apparatus FCS, as shown in
Furthermore, with the afore-mentioned pressure type flow rate control apparatuses, as shown in
Specifically, if a flow rate setting signal Qe=5V is inputted when the conversion rate k of the flow rate conversion circuit 15 is set at 1, a switching computation flow rate signal Qf (Qf=kQc) becomes 5V, and a control valve 2 is operated to open or close until the upstream side pressure P1 reaches 3 (kgf/cm2 abs), thus resulting in that gas of a flow rate Qc=KP1, corresponding to P1=3(kgf/cm2 abs), flows through the orifice 8.
In the case that the range of pressure to control is switched to 0˜2 (kgf/cm2 abs), and the pressure range is provided by the flow rate setting signal Qe of 0˜5V (that is, when a full scale value of 5V gives 2(kgf/cm2 abs)), the afore-mentioned flow rate conversion rate k is thus set at ⅔.
As a result, assuming that the flow rate setting signal Qe=5V is inputted, because of the requirement that Qf=kQc, the switching computation flow rate signal Qf becomes Qf=5×2/3V, and the control valve 2 is operated to open or close until the upstream side pressure P1 becomes 3×2/3=2 (kgf/cm2 abs). In other words, the full scale flow rate is converted so that Qe=5V shows the flow rate Qc=KP1 equivalent to P1=2 (kgf/cm2 abs). It is also the same with the afore-mentioned pressure type flow rate control apparatus shown in,
As stated above, the conventional pressure type flow rate control apparatus is constituted so that the flow rate Qc=KP1, under the orifice upstream side pressure P1 corresponding to Qe=5V (full scale•F.S.), can be switched by adjusting the conversion rate k of the flow rate conversion circuits 15. However, the flow rate switching range is strictly limited to within the range of the flow rate smaller than the flow rate Qc=KP1 under the upstream side pressure P1 corresponding to the afore-mentioned Qe=5V (F.S. value), and the flow rate Qc under the upstream side pressure P1 becomes the flow rate value unequivocally determined by a constant k obtained given a particular orifice diameter, and the like.
In other words, in order for the pressure control range 0˜3 (kgf/cm2 abs) under the orifice upstream side pressure P1 to be provided by the voltage range 0˜5V, and the flow rate value Qc at Qe=5V is switched up to the flow rate, for example, 5 times, it becomes necessary that the orifice itself needs to be changed to a new orifice corresponding to a constant K having a value 5 times that of the previous orifice.
Patent Document 1: TOKU-KAI-HEI No. 8-338546
Patent Document 2: TOKU-KAI No. 2000-66732
Patent Document 3: TOKU-KAI No. 2000-322130
Patent Document 4: TOKU-KAI No. 2003-195948
Patent Document 5: TOKU-KAI No. 2004-199109
Now, with the afore-mentioned conventional pressure type flow rate control apparatuses, as shown in
Also, according to the apparatus of
Furthermore, when using the orifice replacement method in accordance with the apparatus of
In addition, another shortcoming is that the orifice plate cannot be very thin because, as stated before, the orifice 8 is directly clamped and fixed in place as shown in
Another difficulty is, as stated before, that distortion, cracks, corrosion, and the like, caused on the orifice plate by weld heat cannot be prevented even though the orifice plate is constituted so that orifice holding metal ware is welded to a thin orifice plate, and the orifice holding metal ware is positioned and fixed.
It is a primary object of the present invention to solve the afore-mentioned shortcomings of a conventional orifice and a pressure type flow rate control apparatus in which the orifice is used, namely, (a) that it is difficult to manufacture an orifice having a prescribed diameter and shape, and also having stable flow rate characteristics, by using a thin orifice plate, (b) that deformation of the orifice and cracks on the orifice plate can be easily caused by manufacturing a welding type orifice due to thermal stress, (c) that with a pressure type flow rate control apparatus, in which an orifice is used, it is difficult to substantially enlarge a flow rate range by only changing a conversion rate k of the flow rate computation circuit, and (d) that with a conventional orifice replacement type assembly, it takes much time to replace the orifice, and there exists a high risk that an outside leak will be caused, and the like. Another primary object of the present invention is to provide an orifice that makes it possible to secure highly accurate, stable flow rate characteristics by using a very thin orifice plate, and that the orifice is held and fixed to the inside of a fluid passage easily and leak free, and that the orifice is manufactured at low cost and with ease. It is another primary object of the present invention to provide a pressure type flow rate control apparatus for which the orifice is used, and at the same time, to provide an orifice replaceable pressure type flow rate control apparatus that allows, even after shipment from a factory, for the flow rate range to be changed easily and promptly at a worksite by replacing the orifice 8. Yet another primary object of the present invention is to completely eliminate outside leaks from the orifice 8, and to remarkably enhance flow rate control accuracy.
A gasket type orifice, in accordance with a first embodiment of the present invention, is basically constituted so that an orifice base (38a) equipped with a convex portion (38a1) for fitting and an orifice base (38b) equipped with a concave portion (38b1) for fitting are combined, and an orifice plate (38c) is hermetically inserted between the end faces of both orifice bases, and both end faces (38a3), (38b3) of both orifice bases (38a), (38b) are made to be sealing faces for the gasket type orifice.
A gasket type orifice, in accordance with a second embodiment of the present invention, is basically constituted so that a brim portion (38d1) projected inwardly in the inside in the vicinity of one side of a short cylinder-shaped orifice base (38d) for which end faces of both sides are made to be sealing faces, and a thin orifice plate (38c) equipped with an orifice hole on the outside face of the brim portion (38d1), are laser-welded and fixed over the entire periphery of the brim portion and the thin orifice plate.
A pressure type flow rate control apparatus, in accordance with a third embodiment of the present invention, is basically constituted so that a pressure type flow rate control apparatus (A) is equipped with a control valve, a pressure detector, an orifice, a flow rate computation circuit and a computation control circuit, and the afore-mentioned orifice is made to be a gasket type orifice in accordance with either the first embodiment or the second embodiment of the present invention.
The invention, in accordance with a fourth embodiment of the invention, is made so that a pressure type flow rate control apparatus, in accordance with a third embodiment of the invention, includes a valve body (23) of a control valve, which forms the pressure type flow rate control apparatus (A), that is hermetically connected with an inlet side block (40) having a fluid flow passage (40a), a center block (41) equipped with a valve seat (2b), and an outlet side block (42) equipped with an outlet side fluid passage (42a).
The invention, in accordance with a fifth embodiment, is made so that a pressure type flow rate control apparatus, in accordance with a fourth embodiment, includes an installation position of the orifice, of the pressure type flow rate control apparatus (A), disposed between the fluid outlet side of the center block (41) of the control valve and the fluid inlet side of the outlet side fitting block (42).
An orifice changeable pressure type flow rate control apparatus, in accordance with a sixth embodiment of the present invention, is basically constituted so that a valve body 23 of a control valve 2 for a pressure type flow rate control apparatus A is installed between an inlet side fitting block 39 equipped with a coupling portion for a fluid supply pipe and an outlet side fitting block 43 equipped with a coupling portion for a fluid takeout pipe; the fluid inlet side of the valve body 23 and the afore-mentioned fluid outlet side of the inlet side fitting block 39, and also the afore-mentioned fluid outlet side of the valve body 23 and the afore-mentioned fluid inlet side of the outlet side fitting block 43 are hermetically connected with detachability, respectively, thus forming a flow passage for gases through the afore-mentioned control valve 2, and a gasket type orifice 38 of the pressure type flow rate control apparatus A is removably inserted between a gasket type orifice insertion hole 42c provided on the outlet side of the afore-mentioned valve body 23 and a gasket type orifice insertion hole 43b provided on the fluid inlet side of the outlet side fitting block 43.
The invention, in accordance with a seventh embodiment, is constituted so that an orifice changeable pressure type flow rate control apparatus, in accordance with a sixth embodiment, further includes a valve body 23 of the control valve 2, which forms a pressure type flow rate control apparatus A, and that is hermetically connected with the inlet side block 40 having a fluid flow passage 40a, a center block 41 equipped with a valve seat 2b, and an outlet side block 42 equipped with an outlet side fluid passage 42a.
The invention, in accordance with an eighth embodiment, is constituted so that an orifice changeable pressure type flow rate control apparatus, in accordance with the seventh embodiment, further includes a pressure detector insertion hole 41e provided into which to insert a pressure detector 6 of the pressure type flow rate control apparatus A on the center block 41.
A gasket type orifice 38 with regard to the first embodiment of the present invention is constituted so that an orifice plate 38c is closely fitted with hermeticity between both orifice bases 38a, 38b. This makes it possible for the orifice to be caught between both orifice bases 38a, 38b without causing deformation, and the like, even when the orifice plate is made of a very thin metal plate or a metal film. As a result, it is possible to use the orifice plate 38c, having an orifice hole, with very high accuracy, and the orifice 38 itself, as a gasket, can be clamped and fixed closely to a pipe passage and the like by utilizing the outside ends of both orifice bases as seal faces.
A gasket type orifice 38, in accordance with the second embodiment of the invention, is constituted so that the entire periphery of an orifice plate 38c is laser-welded to the outside face of the brim portion 38d1. Therefore, just as the case of the first embodiment of the invention, a gasket type orifice 38 having an orifice hole can be manufactured with very high accuracy and without occurrence of thermal distortion on the orifice plate 38c.
In accordance with a pressure type flow rate control apparatus in accordance with the third embodiment of the present invention, a gasket type orifice 38, in accordance with the first or second embodiments of the invention, is used, thus making it possible to make the orifice 38 itself to be highly accurate, and to secure hermeticity and to nearly completely prevent distortion when the orifice 38 is fixed in place.
In accordance with an orifice changeable pressure type flow rate control apparatus in accordance with the sixth embodiment of the present invention, the orifice can be changed with extreme ease, and hermeticity secured, and distortion nearly completely prevented at the time the orifice is fixed into place. This feature of the invention makes it possible for highly accurate flow rate control to be performed.
An embodiment in accordance with the present invention is described as follows with reference to the drawings.
The afore-mentioned valve body 23 is formed by assembling three members, namely: an inlet side block 40, a center block 41 and an outlet side block 42. The inlet side fitting block 39 and the inlet side block 40 are connected by a fixing bolt (not illustrated) through the mediation of a gasket 35.
The afore-mentioned inlet side block 40 and center block 41 are also connected by a fixing bolt (not illustrated) through the mediation of the gasket type filter 36. The afore-mentioned center block 41 and outlet side block 42 are connected by a fixing bolt (not illustrated) through the mediation of gasket 37. Furthermore, the afore-mentioned outlet side block 42 and outlet side fixing block 43 are hermetically and detachably connected and fixed together by a fixing bolt (not illustrated) through the mediation of a gasket type orifice 38.
The afore-mentioned blocks 39 to 43 are all made of SUS316L-P (W melt) material. A flow-in side pipe fitting (not illustrated), a fluid passage 39a, a fixing bolt screw-in hole (not illustrated) and the like are formed in the inlet side fixing block 39. Also, the fluid passage 40a, the fixing bolt insertion hole (not illustrated), a leak check hole 40b, a gasket insertion hole 40c and the like are formed in the afore-mentioned inlet side block 40. Furthermore, an inlet side fluid passage 41a, an outlet side fluid passage 41b, an insertion hole 41c (i.e., for a valve body 2a) equipped with a valve seat 2b, a gasket insertion hole 41d, a pressure detector insertion hole 41e, a fixing bolt screw-in hole (not illustrated), and the like, are formed in the center block 41.
An outlet side fluid passage 42a, a leak check hole 42b, an orifice gasket insertion hole 42c positioned on the fluid outlet side, a fixing bolt insertion hole (not illustrated), and the like, are formed in the afore-mentioned outlet side block 42. The afore-mentioned outlet side fixing block 43 is provided with an outlet side pipe fitting (not illustrated), a fluid passage 43a, and a fixing bolt screw-in hole (not illustrated) formed therein, which configuration is constituted to be similar to that of the afore-mentioned inlet side fixing block 39. The only difference between the afore-mentioned inlet side fixing block 39 and the outlet side fixing block 43 is that the insertion hole 43c for a gasket type orifice 38 is formed in the fluid inlet side.
As further shown with
The gasket type orifice 38 is used with both a pressure type flow rate control apparatus in accordance with the third embodiment of the present invention, and with an orifice changeable pressure type flow rate control apparatus in accordance with the sixth embodiment of the present invention.
In particular, as shown in
Next, replacement (or exchange) of the gasket type orifice 38 is explained as follows. When a need to replace the gasket type orifice 38 occurs, for example, due to changes of the flow rate of gases to be controlled or there is a change in the type of gases to be used, and the like, first, as shown in
Next, a new gasket type orifice 38 is inserted inside the gasket insertion hole 42c of the afore-mentioned outlet side block 42, and both blocks 40, 42 are, then, fixed to the fixing blocks 39, 43 respectively as before.
It is not necessary at all for the piping systems to be removed at the time of the gasket type orifice 38 is replaced because the gas inlet side pipe and the gas outlet side pipe are both connected to the connecting joints of the inlet side fixing block 39 and the outlet side fixing block 43, respectively, and both blocks 39, 43 are not moved at all.
Upon completion of replacement of the afore-mentioned gasket type orifice 38, the flow rate to be set and the flow rate to be controlled are newly adjusted. For example, as shown in
The present invention is applicable to all fluid equipment for which an orifice is used, and to fluid flow rate control apparatuses which are so constituted so that flow rate control of fluids is performed by using an orifice, and is mainly utilized in fields such as semiconductor manufacturing, chemical industry, pharmaceutical industry, food processing industry, and the like.
Number | Date | Country | Kind |
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2005-245804 | Aug 2005 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2006/309368 | 5/10/2006 | WO | 00 | 2/12/2009 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2007/023597 | 3/1/2007 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
1938460 | Muff | Dec 1933 | A |
2229903 | Schmohl et al. | Jan 1941 | A |
3081942 | Maclay | Mar 1963 | A |
3375845 | Behm | Apr 1968 | A |
3411669 | Puster | Nov 1968 | A |
3827457 | Vutz et al. | Aug 1974 | A |
3830256 | Cox | Aug 1974 | A |
3831845 | Pacht | Aug 1974 | A |
3905394 | Jerde | Sep 1975 | A |
3963043 | Cota et al. | Jun 1976 | A |
3999572 | Mohr | Dec 1976 | A |
4030523 | Cram et al. | Jun 1977 | A |
4089007 | Perry et al. | May 1978 | A |
4313465 | Holzem et al. | Feb 1982 | A |
4431020 | Kowalski | Feb 1984 | A |
4478246 | Sherrod | Oct 1984 | A |
4518011 | Stoll | May 1985 | A |
4633911 | Lohn | Jan 1987 | A |
4979639 | Hoover et al. | Dec 1990 | A |
5069252 | Kendrick et al. | Dec 1991 | A |
5269334 | Eastman | Dec 1993 | A |
5329965 | Gordon | Jul 1994 | A |
5645866 | Eckardt et al. | Jul 1997 | A |
5669408 | Nishino et al. | Sep 1997 | A |
5735787 | Lorey | Apr 1998 | A |
5791369 | Nishino et al. | Aug 1998 | A |
5816285 | Ohmi et al. | Oct 1998 | A |
5875817 | Carter | Mar 1999 | A |
5938425 | Damrath et al. | Aug 1999 | A |
6314992 | Ohmi et al. | Nov 2001 | B1 |
6422264 | Ohmi et al. | Jul 2002 | B2 |
6539968 | White et al. | Apr 2003 | B1 |
6591851 | Palten et al. | Jul 2003 | B1 |
6997202 | Olander | Feb 2006 | B2 |
Number | Date | Country |
---|---|---|
3-033566 | Feb 1991 | JP |
06-004139 | Jan 1994 | JP |
08-087335 | Apr 1996 | JP |
08-338546 | Dec 1996 | JP |
09-330128 | Dec 1997 | JP |
10-055218 | Feb 1998 | JP |
11-125398 | May 1999 | JP |
11-265215 | Sep 1999 | JP |
11-265216 | Sep 1999 | JP |
2000-020135 | Jan 2000 | JP |
2000-066732 | Mar 2000 | JP |
2000-322130 | Nov 2000 | JP |
2003-195948 | Jul 2003 | JP |
2004-510225 | Apr 2004 | JP |
2004-243333 | Sep 2004 | JP |
2004-278614 | Oct 2004 | JP |
2005-115501 | Apr 2005 | JP |
2005-149075 | Jun 2005 | JP |
2005-180527 | Jul 2005 | JP |
2004-199109 | Oct 2007 | JP |
02-25391 | Mar 2002 | WO |
Entry |
---|
International Search Report and Written Opinion completed Jul. 11, 2006 and mailed Jul. 25, 2006 in the corresponding international application No. PCT/JP2006/309368. |
http://www.weisz.com/informacion/tablas%20tecnicas—pdf/Steel—grades—equivalence—table.pdf, downloaded Sep. 20, 2012. |
International Search Report issued in related application PCT/JP2006/312952, completed Sep. 6, 2006 and mailed Sep. 19, 2006. |
Office Action issued Jun. 28, 2012 in co-pending related U.S. Appl. No. 11/913,277. |
Office Action issued in co-pending related U.S. Appl. No. 13/763,178 on Dec. 6, 2013. |
Number | Date | Country | |
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20090171507 A1 | Jul 2009 | US |