JP4667964B2 - Flow control valve - Google Patents

Description

  The present invention relates to a flow rate adjusting valve that is used in a corrosive atmosphere such as a semiconductor manufacturing apparatus and adjusts a valve opening degree using a differential screw.

  For example, in an etching apparatus in a semiconductor manufacturing process, a wafer is placed in a chamber and rotated, a chemical solution is supplied to the wafer at a constant flow rate, and a film on the wafer surface is uniformly etched by a certain amount. . Since the flow rate of the chemical solution affects the quality of the thin film, it must be accurately controlled. As shown in FIG. 9 and FIG. 10, for example, flow rate adjusting valves 100 and 200 that adjust the valve opening by a differential screw are known as devices for adjusting the flow rate of a chemical solution. FIG. 9 shows a cross-sectional view of the flow control valve 100 of the first conventional example, and FIG. 10 shows a cross-sectional view of the flow control valve 200 of the second conventional example.

  In the flow rate adjusting valve 100 shown in FIG. 9, the slide stem 103 pushes down the diaphragm valve body 101 against the elastic force of the spring 105 and contacts the valve seat 104. The slide stem 103 is slidably held by the base tube 109, and the spindle 106 is screwed from above. An outer sleeve 107 is fixed to the upper end portion of the spindle 106, and the outer peripheral surface of the outer sleeve 107 and the inner peripheral surface of the base tube 109 are screwed together. A handle 110 is fixed to the outer sleeve 107. In such a flow rate adjusting valve 100, the differential screw is composed of an inner screw 121 provided between the slide stem 103 and the spindle 106 and an outer screw 122 provided between the outer sleeve 107 and the base pipe 109. Is done.

  When the handle 110 is rotated and the outer sleeve 107 is moved up and down by the screw feed of the outer screw 122, the flow rate adjusting valve 100 moves up and down while rotating integrally with the outer sleeve 107, and the screw feed of the inner screw 121. The slide stem 103 is moved up and down. At this time, the lift amount of the slide stem 103 is the difference between the pitch of the inner screw 121 and the pitch of the outer screw 122. The position of the diaphragm valve body 101 is adjusted according to the lift amount of the slide stem 103, and the valve opening degree is adjusted (see, for example, Patent Document 1).

  The flow rate adjusting valve 200 shown in FIG. 10 is configured by connecting the flow path block 213, the cylinder 201, and the guide tube 206 with screws. A piston 202 is slidably loaded in the cylinder 201, and a diaphragm valve body 203 is connected to the lower end of the piston 202. A spring 204 is contracted between the guide tube 206 and the piston 202, and always presses the diaphragm valve body 203 toward the valve seat 205 via the piston 202. A valve opening adjustment rod 207 and a stroke adjustment rod 208 are slidably loaded in the guide tube 206, and the upper end of the valve opening adjustment rod 207 that abuts against the upper end surface of the piston 202 is screwed into the stroke adjustment rod 208 from below. It has been entered. The stroke adjusting rod 208 has an upper end protruding from the guide tube 206 to the outside, and a handle 209 is fixed to the protruding portion. The handle 209 has a bag shape, and an inner peripheral surface thereof is screwed to an outer peripheral surface of the guide tube 206. In such a flow rate adjusting valve 200, a differential screw is provided between the inner screw 211 provided between the upper end of the valve opening adjusting rod 207 and the stroke adjusting rod 208, and between the handle 209 and the guide tube 206. The outer screw 212 is arranged concentrically and is designed to reduce the overall height.

  When the handle 209 is rotated in the predetermined direction K1, the flow rate adjusting valve 200 is moved by the screw feed of the inner screw 211 and the outer screw 212, so that the valve opening adjusting rod 207 is raised and the diaphragm valve body 203 acts on the pressure receiving surface. The pressure rises until the piston 202 abuts against the valve opening adjustment rod 207 by the pressure. On the other hand, when the handle 209 is rotated in the direction K2 opposite to the predetermined direction, the valve opening degree adjusting rod 207 is lowered by the screw feed of the inner screw 211 and the outer screw 212, and the diaphragm valve body 203 approaches the valve seat 205. Lower (see, for example, Patent Document 2).

Utility Model Registration No. 2541613 JP 2004-225839 A

  However, the flow control valves 100 and 200 shown in FIGS. 9 and 10 cannot be used in a highly corrosive atmosphere. The flow rate adjusting valves 100 and 200 reduce the pitch difference between the inner screws 121 and 211 and the outer screws 122 and 212 by applying fine screws to the inner screws 121 and 211 and the outer screws 122 and 212, thereby reducing the valve opening degree. adjust. The inner screws 121 and 211 and the outer screws 122 and 212 of the differential screw are required to have a strength that can withstand fluid pressure, frictional resistance, and the like. The conventional flow rate adjusting valves 100 and 200 include the inner screws 121 and 211 and the outer screws. 122 and 212 were made of a rigid metal. On the other hand, the flow regulating valves 100 and 200 are exposed to a corrosive atmosphere when controlling a highly corrosive chemical. Therefore, when the flow control valves 100 and 200 are used in a highly corrosive atmosphere, the inner screws 121 and 211 and the outer screws 122 and 212 become corroded and become thin, and the valve is opened based on the rotation amount of the differential screw. The degree could not be adjusted accurately. In this regard, it can be considered that the differential screws of the flow rate adjusting valves 100 and 200 are made of resin instead of metal. However, the flow control valves 100 and 200 support the outside of the base tube 109 that supports the outside of the external screw 122, the slide stem 103 that supports the outside of the internal screw 121, the guide tube 206 that supports the outside of the external screw 211, and the outside of the external screw 212. Since the thickness of the stroke adjusting rod 208 is thin, simply changing the material of the differential screw from metal to resin cannot secure the strength that can withstand fluid pressure, frictional resistance, and the like.

Therefore, when the differential screw of the flow rate adjusting valve 100 shown in FIG. 9 or the flow rate adjusting valve 200 shown in FIG. 10 is made of resin, the slide stem 103 (see FIG. 9) that supports the outer side of the inner screw 121 and the inner screw 211 The thickness of the stroke adjusting rod 208 (see FIG. 10) that supports the outside of the outer thread 122, the base tube 109 (see FIG. 9) that supports the outside of the external screw 122, and the handle 209 (see FIG. 10) that supports the outside of the external screw 212 The thickness has to be increased in the direction to increase the strength, and the size has increased in the radial direction.
In addition to this, the flow rate adjusting valve 100 shown in FIG. 9 and the flow rate adjusting valve 200 shown in FIG. 10 have inner screws 121, 211 and outer screws 122, 212 arranged concentrically, so that the components constituting the differential screw mechanism Was more expensive.

  Accordingly, the present invention has been made to solve the above-described problems, and provides a small and inexpensive flow rate adjustment valve capable of accurately adjusting the flow rate even when used in a corrosive atmosphere. With the goal.

The flow regulating valve according to the present invention has the following configuration.
(1) In a flow rate adjusting valve that adjusts the position of a diaphragm valve element that contacts or separates from a valve seat using a differential screw, a resin-made holding member and a resin-made flow channel block provided with the valve seat A resin cover is formed by stacking and connecting resin covers, and the exterior is configured and stored in the storage chamber formed between the holding member and the cover so as to be movable in the axial direction and connected to the diaphragm valve body. A thick boss portion is formed at the upper end of the movable member and the cover , and is inserted from the boss portion so as to be movable in the axial direction . One end is located in the storage chamber and is connected to the movable member. A resin-made stroke adjusting member formed in a rod shape whose end protrudes to the outside, and the differential screw is a first connecting screw provided with resin at a connecting portion between the movable member and the stroke adjusting member. , The stroke adjusting member and the cap And a second coupling screw provided with a resin on the surface of sliding contact between the boss portion of the over, between the inner wall of the storage chamber and the movable member, put the first axis issuing an axis of said movable member The member is disposed in an annular groove formed on the outer peripheral surface of the upper end of the movable member, and a second axis is formed between the convex portion of the movable member and the inner wall of the through hole of the holding member. The pivoting member is disposed in an annular groove formed on the outer peripheral surface of the lower end of the convex portion, and at least the first pivoting member presses the movable member in the axial direction to prevent rattling. It is characterized by.
(2) In the flow regulating valve described in (1), the storage chamber is partitioned into a primary chamber opposite to the valve and a secondary chamber on the valve side across the movable member, and a compressed fluid is contained in the secondary chamber. Is filled .

Flow control valve of the present invention is accommodated chamber formed between the resin holding member and the resin cover, a resin of the movable member is movably accommodated in the axial direction to the housing chamber, the rod-shaped Thick boss part is formed at the upper end of the cover , and the resin stroke adjustment member molded in the shape is inserted in the axial direction so that it can move in the axial direction, one end is connected to the movable member, and the thrust of the stroke adjustment member Is transmitted to the diaphragm valve body through the movable member to adjust the valve opening. A first connecting screw is provided with a resin at a connecting portion between the movable member and the stroke adjusting member, and a second connecting screw is provided with a resin on a sliding contact surface between the stroke adjusting member and the boss portion of the cover, The first connecting screw and the second connecting screw are arranged in series in the axial direction to constitute a differential screw. In the flow rate adjusting valve of the present invention, the differential screw mechanism is composed of four parts including a resin holding member, a cover, a movable member, and a stroke adjusting member, so that the differential screw is thin even when used in a corrosive atmosphere. The position of the diaphragm valve body can be adjusted based on the rotation amount of the stroke adjusting member, and the flow rate can be adjusted accurately. In addition, since the flow regulating valve of the present invention supports the outside of the first connecting screw with a movable member and supports the outside of the second connecting screw with the boss portion of the cover , in order to ensure the strength of the resin differential screw, It is not necessary to increase the thickness of the movable member or the cover in the radial direction, and it is small. Furthermore, since the flow regulating valve of the present invention has the first connecting screw and the second connecting screw arranged in series, the number of parts is less than that in the case where the first and second connecting screws are arranged concentrically and is inexpensive. is there.
The flow rate control valve of the present invention, that the first shaft centering member prevents disposed in an annular groove formed on the upper end outer peripheral surface of the movable member backlash by pressing the movable member in the axial direction Accordingly, since the movable member is moved in the axial direction following a certain locus, the first connecting screw and the second connecting screw are correctly screwed together to transmit thrust, and the valve opening can be adjusted accurately.
In addition, the flow regulating valve of the present invention further ensures the movable member by preventing rattling by pressing the movable member in the axial direction at a position different from the first pivoting member. Since the first connection screw and the second connection screw are properly screwed together to transmit a thrust, the valve opening can be adjusted more accurately.
Further, the flow regulating valve of the present invention causes the pressure in the secondary chamber to act on the movable member in the same direction as the fluid pressure acting on the diaphragm valve body by filling the secondary chamber with the compressed fluid. Backlash of the connecting screw and the second connecting screw is prevented. Therefore, flow control valve of the present invention, the movable member when moved in the axial direction to adjust the valve opening, not rattle a first connection screw and a second coupling screw can be accurately adjust the flow rate. In addition, a metal spring for preventing back-crash is not required, and higher reliability can be secured when used in a corrosive atmosphere.

  Next, an embodiment of a flow control valve according to the present invention will be described with reference to the drawings.

(First embodiment)
First, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of the flow regulating valve 1A. FIG. 2 is a view showing a state where the flow rate adjusting rod of the flow rate adjusting valve 1A shown in FIG. 1 is moved to the upper limit position. 3 is a cross-sectional view taken along the line AA in FIG. FIG. 4 is a right side view of the flow rate adjusting valve shown in FIG. 1 and shows a screw fastening portion in section.
The flow rate adjusting valve 1A according to the present embodiment is incorporated in an etching apparatus used in a semiconductor manufacturing process, and controls the flow rate of a chemical solution dropped on a wafer, as in the prior art. The flow rate adjusting valve 1A has a main component made of resin so that it can be used in a corrosive atmosphere.

  As shown in FIG. 4, the flow rate control valve 1 </ b> A includes a flow path block 2, a cylinder (holding member) 3, and a cover 4, and through four bolts V from above and a nut insert-molded on the mounting plate 19. It is integrated by fastening the tip to N, and the appearance is configured. In the cover 4, the opening through which the bolt V is inserted is closed by the cap C, and the bolt V is blocked from the corrosive atmosphere.

  As shown in FIGS. 1 and 2, the flow path block 2 is made of a resin having excellent heat resistance and corrosion resistance, such as PTFE (polytetrafluoroethylene) and PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer). It is molded into a block shape. The flow path block 2 is provided with a first port 5 and a second port 6, and communicates via a valve seat 7 formed between the first port 5 and the second port 6. The cylinder 3 is formed by molding a resin having a high corrosion resistance such as PP (polypropylene) and relatively easy to mold into a cylindrical block shape, and includes a flange extending radially in the outer peripheral surface. The cover 4 is formed of a resin such as PP that has a high corrosion resistance and is relatively easy to mold, and is formed between the lower end surface of the cover 4 and the upper end surface of the flow path block 2. Is put on the cylinder 3 so as to sandwich it.

  A resin-made diaphragm valve element 8 is sandwiched between the flow path block 2 and the cylinder 3. The diaphragm valve body 8 is formed by molding a resin having excellent heat resistance and corrosion resistance, such as PTFE, into a substantially circular shape, and a conical valve body portion 9 is provided at the center. Diaphragm valve body 8 adjusts the flow rate by inserting the tip of valve body portion 9 into valve seat 7 and changing the cross-sectional area formed between the outer peripheral surface of valve body portion 9 and the inner peripheral surface of valve seat 7. I do.

  A storage chamber 10 is formed between the cylinder 3 and the cover 4 to store the movable member 11. The movable member 11 is formed by molding a resin having relatively high hardness, heat resistance, and chemical resistance such as PVDF (polyvinylidene fluoride) and PCTFE (polychlorotrifluoroethylene) into a substantially cylindrical shape. The movable member 11 is provided with a convex portion 12 in a cylindrical shape at the lower end portion in the figure, and slidably penetrates the convex portion 12 through a through hole 3 a formed in the cylinder 3 and is connected to the diaphragm valve body 8. The movable member 11 is provided with a bottomed hole from the upper end surface in the figure, and a first female screw 11a is integrally formed of resin on the inner peripheral surface thereof. As shown in FIG. 3, the guide groove 3b is formed in the cylinder 3 by notching the upper end surface in the axial direction, and the movable member 11 is chamfered at two outer peripheral surfaces to form a guide surface 11b. 11b is supported by the guide groove 3b and stopped.

  The cover 4 is formed with a boss portion 4a, a stroke adjusting rod (stroke adjusting member) 13 is inserted from the boss portion 4a so as to be movable in the vertical direction, and a lower end portion located in the storage chamber 10 is connected to the movable member 11. To do. The stroke adjusting rod 13 is formed by molding a resin having relatively high hardness, heat resistance, and chemical resistance such as PVDF or PCTFE into a rod shape. The stroke adjusting rod 13 has a first male screw 13a integrally formed of resin on the outer periphery of the lower end, and the first male screw 13a is screwed into the first female screw 11a of the movable member 11 so that the first connecting screw 14 is engaged. Constitute. In the stroke adjusting rod 13, a second male screw 13 b is integrally formed of resin above the first male screw 13 a constituting the first connecting screw 14. In the cover 4, the second female screw 4 b is integrally formed of resin on the inner periphery of the through hole that passes through the stroke adjusting rod 13, and the second male screw 13 b of the stroke adjusting rod 13 is connected to the second female screw of the cover 4. The second connecting screw 15 is configured by being screwed to the screw 4b. The first connection screw 14 and the second connection screw 15 are provided in the same direction, and the pitch of the second connection screw 15 is set larger than the pitch of the first connection screw 14. The position of the movable member 11 and thus the diaphragm valve body 8 is finely adjusted by the pitch difference of the screw 15. That is, in the flow rate adjusting valve 1A, a differential screw is constituted by the resin first connecting screw 14 and the second connecting screw 15, and no metal is used for the differential screw.

  When the differential screw is made of resin, the strength against fluid pressure, frictional resistance, etc. becomes a problem. In the flow rate adjusting valve 1A of the present embodiment, the movable member 11 and the stroke adjusting rod 13 are made of a relatively hard material such as PVDF or PCTFE, and the first female screw 11a, the first male screw 13a, and the second male screw 13b. Ensure the strength of. And since the movable member 11 which comprises the 1st internal thread 11a has a block shape and is thick, the intensity | strength which supports the 1st internal thread 11a located in the outer side of the 1st connection screw 14 is ensured. On the other hand, the cover 4 is made of resin (PP or the like) whose hardness is lower than that of PVDF or PCTFE, but the second female screw 4b is provided in the boss portion 4a so that the periphery of the second connecting screw 15 is thick. Therefore, the strength to support the second female screw 4b located outside the second connecting screw 15 is ensured.

  Note that a knob 16 is provided at the upper end of the stroke adjusting rod 13 so that the stroke adjusting rod 13 can be easily rotated manually.

  By the way, the flow rate adjusting valve 1A includes a sliding contact surface of the stroke adjusting rod 13 and the cover 4, a sliding contact surface of the stroke adjusting rod 13 and the movable member 11, and a convex portion 12 of the movable member 11 and the through hole 3a of the cylinder 3. The movable member 11 is positioned by the slidable contact surface, and the axis is aligned. However, since the stroke adjusting rod 13, the cover 4, the movable member 11, and the cylinder 3 are made of resin, it is difficult to process and mold them with high accuracy, and there is a gap (backlash) between parts when assembled. Easy to grow. Further, when the stroke adjusting rod 13 moves to the upper limit position as shown in FIG. 2, the sliding contact area between the movable member 11 and the stroke adjusting rod 13 decreases, and the movable member 11 and the stroke adjusting rod 13 are tilted and tilted. It becomes easy. If the movable member 11 or the stroke adjusting rod 13 is tilted, the trajectory of the movable member 11 may not be stable, and the valve opening may not be adjusted accurately.

  Therefore, the movable member 11 is provided with an O-ring (first axising member) 17 made of rubber such as fluoro rubber or perfluoroelastomer in an annular groove formed on the outer peripheral surface of the upper end portion. The O-ring 17 is crushed in the radial direction and elastically deformed. Further, the movable member 11 is formed on the outer peripheral surface of the convex portion 12, and an O-ring (second axising member) 18 made of rubber such as fluororubber or perfluoroelastomer is attached to the annular groove. The O-ring 18 is crushed in the radial direction between 12 and the inner wall of the through hole 3a of the cylinder 3 to be elastically deformed. The elastically deformed O-rings 17 and 18 press the movable member 11 in the axial direction by the restoring force, and the movable member 11 is centered.

Here, the applicants conducted an experiment to examine the function of the O-ring 17. FIG. 5 shows a circuit diagram of the apparatus used in the experiment for examining the function of the centering member.
In the apparatus used in the experiment, the pressure gauge 21, the flow meter 22, and the evaluation sample S are sequentially arranged from the upstream side. For the evaluation sample S, the flow rate adjusting valve 1A of the present embodiment having the O-ring 17 and the flow rate adjusting valve obtained by removing the O-ring 17 from the flow rate adjusting valve 1A of the present embodiment were used. In the experiment method, first, the flow rate adjustment valve to be the evaluation sample S is set in an open state, pressure (about 0.1 MPa) is applied from the first port 5 of the flow rate adjustment valve to be the evaluation sample S, and the flow meter 22 After measuring the flow rate, the stroke adjusting rod 13 is rotated several times in the valve closing direction, and then the flow rate adjusting valve to be the evaluation sample S is set to the valve open state again, and the pressure (about 0.1 MPa from the first port 5 is set. ) And measure the flow rate with the flow meter 22. This series of experiments was repeated three times to confirm changes in flow rate.

FIG. 6 shows the experimental result of the flow rate adjusting valve not having the O-ring 17, and FIG. 7 shows the experimental result of the flow rate adjusting valve 1 A having the O-ring 17.
No flow regulating valve O-ring 17, as shown in FIG. 6, the first flow rate 4603cm ³ / min, the second-time flow rate of about 4740cm ³ / min, the third-time flow rate is 4624Cm ³ / min. The second flow rate increased by about 137 cm ³ / min with respect to the first flow rate, and the rate of change was about + 3%. In addition, the third flow rate decreased by about 116 cm ³ / min with respect to the second flow rate, and the rate of change was about −2%.
On the other hand, as shown in FIG. 7, the flow rate adjusting valve 1A having the O-ring 17 has a first flow rate of 4670 cm ³ / min, a second flow rate of about 4682 cm ³ / min, and a third flow rate of 4678 cm. ³ / min. The second flow rate increased by about 12 cm ³ / min with respect to the first flow rate, and the rate of change was about + 0.2%. In addition, the third flow rate decreased by about 4 cm ³ / min with respect to the second flow rate, and the rate of change was about −0.1%.

  From this experimental result, the flow rate adjusting valve without the O-ring 17 changes the flow rate by about 2 to 3% every time the movable member 11 is moved in the axial direction and the opening / closing operation is repeated, whereas the O-ring 17 The flow rate adjusting valve 1A having a flow rate of only 0.1 to 0.2% changes even when the movable member 11 is moved in the axial direction and the opening and closing operation is repeated, and the flow rate adjusting valve having the O-ring 17 It has been found that the flow rate change rate of 1A can be suppressed to about 10% of the flow rate change rate of the flow rate adjusting valve without the O-ring 17. This is because the flow rate adjusting valve having no O-ring 17 is not stable due to rattling of the movable member 11, and the cross-sectional area between the diaphragm valve body 8 and the valve seat 7 when the valve is opened varies. On the other hand, the flow regulating valve 1A having the O-ring 17 moves the movable member 11 along the same track in the axial direction, and the cross-sectional area between the diaphragm valve body 8 and the valve seat 7 when the valve is opened is different. This is considered to be because the flow rate is stable.

  Such a flow regulating valve 1A is attached to the etching apparatus via the mounting plate 19, and in the state of FIG. 1, the valve body portion 9 of the diaphragm valve body 8 closes the valve seat 7 and flows in from the first port 5. The chemical solution is blocked at the valve seat 7. Thereafter, when the knob 16 is rotated in the predetermined direction K1 in FIG. 1 and the stroke adjusting rod 13 is raised, the movable member 11 is raised according to the pitch difference between the first connecting screw 14 and the second connecting screw 15, and the diaphragm valve The body 3 is separated from the valve seat 7. The chemical liquid is output from the second port 6 after the flow rate is adjusted in a gap formed between the valve body portion 9 and the valve seat 7. Thereafter, when the knob 16 is rotated in the direction K2 opposite to the predetermined direction and the stroke adjusting rod 13 is lowered, the movable member 11 is lowered according to the pitch difference between the first connecting screw 14 and the second connecting screw 15, and the diaphragm The valve body 3 is brought close to the valve seat 7 to reduce the valve opening, thereby reducing the flow rate.

  Accordingly, in the flow rate adjusting valve 1A of the present embodiment, the storage chamber 10 is formed between the resin cylinder 3 and the resin cover 4, and the resin movable member 11 moves in the storage chamber 10 in the axial direction. The stroke adjusting rod 13 made of resin is inserted into the cover 4 and one end is connected to the movable member 11, and the thrust of the stroke adjusting rod 13 is transmitted to the diaphragm valve body 8 via the movable member 11. Adjust the valve opening. A first connecting screw 14 is provided with a resin at a connecting portion between the movable member 11 and the stroke adjusting rod 13, and a second connecting screw 15 is provided with a resin on a sliding contact surface between the stroke adjusting rod 13 and the cover 4. The first connecting screw 14 and the second connecting screw 15 are arranged in series in the axial direction to constitute a differential screw. Since the differential screw mechanism of the flow rate adjusting valve 1A of the present embodiment is composed of four parts of the resin cylinder 3, the cover 4, the movable member 11, and the stroke adjusting rod 13, even when used in a corrosive atmosphere, The differential screw is not thinned, and the position of the diaphragm valve body 8 can be adjusted based on the rotation amount of the stroke adjusting rod 13 to accurately adjust the flow rate. Moreover, since the flow regulating valve 1A of this embodiment supports the outer side of the 1st connection screw with the movable member 11, and supports the outer side of the 2nd connection screw 15 with the cover 4, in order to ensure the intensity | strength of a resin-made differential screw. Moreover, it is not necessary to increase the thickness of the movable member 11 and the cover 4 in the radial direction, and the size is small. Furthermore, since the flow regulating valve 1A of this embodiment arranges the first connecting screw 14 and the second connecting screw 15 in series, like the flow regulating valve 100 shown in FIG. 9 and the flow regulating valve 200 shown in FIG. Compared with the case where the inner screws 121 and 211 and the outer screws 122 and 212 are arranged concentrically, the number of parts is small and the cost is low.

  Further, in the flow rate adjusting valve 1A of the present embodiment, the O-rings 17 and 18 press the upper and lower positions of the movable member 11 in the drawing in the axial direction to prevent rattling, and the movable member 11 always follows a constant locus. Therefore, the first connecting screw 14 and the second connecting screw 15 are properly screwed together to transmit thrust, and the valve opening can be adjusted accurately. In particular, the flow rate adjusting valve 1A is effective in adjusting the fine flow rate of the chemical solution because the flow rate change rate can be suppressed to only about 0.1 to 0.2% by providing the O-ring 17 (see FIG. 7). is there.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 8 is a cross-sectional view of the flow regulating valve 1B.
The flow rate adjusting valve 1B of the present embodiment is different from the flow rate adjusting valve 1A of the first embodiment in that a compressed fluid is sealed on the secondary side of the movable member 11 to prevent backlash of the differential screw. Therefore, here, it demonstrates centering on the point which is different from the flow regulating valve 1A of 1st Embodiment, attaches | subjects the code | symbol same as 1st Embodiment to a common structure, and abbreviate | omits description suitably.

  In the flow regulating valve 1B of the present embodiment, a storage chamber 10 formed between the cylinder 3 and the cover 4 is partitioned into a primary chamber 10A on the opposite side of the valve and a secondary chamber 10B on the valve side across the movable member 11. Is done. Between the movable member 11 and the cover 4, the O-ring 17 is held in a state of being crushed in the radial direction, and the space between the movable member 11 and the cover 4 is hermetically sealed. An annular groove 32 is formed on the outer peripheral surface of the cylinder 3, and a rubber O-ring 31 such as fluoro rubber or perfluoroelastomer is crushed in the radial direction between the annular groove 32 and the cover 4, and the cylinder 3 and the cover. 4 is sealed airtight. Further, the O-ring 18 is held between the convex portion 12 of the movable member 11 and the through hole 3 a of the cylinder 3 in a state of being crushed in the radial direction, and the convex portion 12 of the movable member 11 and the cylinder 3 are penetrated. The space between the holes 3a is hermetically sealed. The air supply / exhaust port 33 established in the cover 4 communicates with the secondary chamber 10B thus secured in airtightness, and compressed fluid is supplied from a compressed fluid supply means (not shown) connected to the air supply / exhaust port 33. . The air supply / exhaust port 33 is sealed with a cap 34 after the secondary chamber 10B is filled with the compressed fluid. At this time, the secondary chamber 10B is filled with the compressed fluid so that the internal pressure becomes equal to or higher than the atmospheric pressure when the movable member 11 moves to the upper limit position.

  Generally, a screw is provided so that the screw can be screwed in the axial direction and moved. The flow rate adjusting valve 1B has a backlash on the first and second connecting screws 14 and 15, and when the secondary chamber 10B is not pressurized, there is a possibility that backlash may occur during the flow rate adjustment. If a metal spring is contracted in the secondary chamber 10B to prevent back crash, there is a problem from the viewpoint of corrosion resistance. However, the flow rate adjusting valve 1B of the present embodiment fills the secondary chamber 10B with a compressed fluid, so that the pressure in the secondary chamber 10B is the same direction as the fluid pressure acting on the diaphragm valve body 8 with respect to the movable member 11. This prevents backlash of the first connecting screw 14 and the second connecting screw 15. Therefore, when the flow regulating valve 1B moves the movable member 11 in the axial direction and adjusts the valve opening degree, the first male screw 13a, the first female screw 11a, and the second connecting screw 14 of the first connecting screw 14 are used. The second male screw 13b and the second female screw 4b of the screw 15 are not always in contact with the same end face, and the flow rate can be adjusted accurately. In addition, when a metal spring for preventing backlash is used, the spring may be corroded and the elastic pressure may be reduced, and backlash may not be prevented. When pressure is used, even if the flow control valve 1B is used in a corrosive atmosphere, the stroke adjustment rod 13 can always be pushed up with a stable force to prevent back crash, ensuring higher reliability. it can.

Although the embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments, and various applications are possible.
(1) For example, in the above-described embodiment, the rubber O-rings 17 and 18 are used as the first and second pivoting members. However, if only the pivoting of the movable member 11 is intended, it is more elastic than the rubber material. A resin bush or the like having a small amount of deformation may be used as the first and second pivoting members. Further, if the purpose is to center and seal the movable member 11, a deformed seal member such as a rubber Y packing may be used as the first and second centering members. That is, the first and second axising members may be any members that can be axially pressed by pressing the movable member 11 in the axial direction.
(2) For example, in the above embodiment, the knob is manually rotated, but a motor may be connected to the upper end portion of the stroke adjusting rod to automatically rotate the stroke adjusting rod.
(3) For example, in the above embodiment, the needle valve structure is applied to the flow rate adjusting valves 1A and 1B, but the poppet valve structure may be applied to the flow rate adjusting valves 1A and 1B.
(4) For example, in the second embodiment, the cap is closed with the compressed fluid filled in the secondary chamber, and the compressed fluid is sealed in the secondary chamber, but the compressed fluid supply device is connected to the supply / exhaust port. Alternatively, the compressed fluid may be constantly supplied to the secondary chamber to keep the pressure in the secondary chamber at a certain level or higher.

It is sectional drawing of the flow regulating valve concerning 1st Embodiment of this invention, Comprising: A valve closing state is shown. It is a figure which shows the state which moved the flow regulating rod of the flow regulating valve shown in FIG. 1 to the upper limit position. It is AA sectional drawing of FIG. It is a right view of the flow regulating valve shown in FIG. 1, Comprising: The fastening part of the screw is shown by the cross section. It is the circuit diagram of the apparatus used in the experiment which investigates the function of a shafting member. It is a figure for demonstrating the function of a pivoting member, Comprising: Flow volume adjustment was repeatedly performed about the flow regulating valve which does not have a 1st pivoting member, and the flow volume change was investigated. The vertical axis in the figure indicates the flow rate, and the horizontal axis in the figure indicates the number of repetitions. It is a figure for demonstrating the function of a pivoting member, Comprising: Flow volume adjustment was repeatedly performed about the flow regulating valve which has a 1st pivoting member, and the flow volume change was investigated. The vertical axis in the figure indicates the flow rate, and the horizontal axis in the figure indicates the number of repetitions. It is sectional drawing of the flow regulating valve concerning 2nd Embodiment of this invention, Comprising: A valve closing state is shown. It is sectional drawing of the flow regulating valve of the 1st prior art example. It is sectional drawing of the flow regulating valve of a 2nd prior art example.

Explanation of symbols

1A, 1B Flow rate adjustment valve 2 Flow path block 3 Cylinder (holding member)
3a Through-hole 4 Cover 7 Valve seat 8 Diaphragm valve element 10 Storage chamber 10B Secondary chamber 11 Movable member 12 Convex portion 13 Stroke adjustment rod (Stroke adjustment member)
14 1st connection screw 15 2nd connection screw 17 O-ring (1st axising member)
18 O-ring (second shafting member)

Claims (2)

In the flow rate adjustment valve that adjusts the position of the diaphragm valve element that contacts or separates from the valve seat using a differential screw,
By laminating and connecting a resin holding member and a resin cover to the resin flow path block provided with the valve seat, the appearance is configured,
A resin-made movable member that is accommodated in a storage chamber formed between the holding member and the cover so as to be movable in the axial direction, and connected to the diaphragm valve body;
A thick boss is formed at the upper end of the cover , and is inserted from the boss so as to be movable in the axial direction . One end is located in the storage chamber and is connected to the movable member, and the other end protrudes to the outside. A stroke adjustment member made of resin molded into a rod shape ,
The differential screw is provided with a resin on a sliding contact surface between a first connecting screw provided with a resin at a connecting portion between the movable member and the stroke adjusting member, and the boss portion of the cover with the stroke adjusting member. A second connecting screw,
A first pivoting member for projecting the axis of the movable member is disposed in an annular groove formed on the outer peripheral surface of the movable member between the movable member and the inner wall of the storage chamber;
Between the convex part of the said movable member and the inner wall of the through-hole of the said holding member, the 2nd axial member which takes out the axis | shaft of the said movable member was arrange | positioned in the annular groove formed in the lower end outer peripheral surface of the said convex part . that,
The flow rate adjusting valve characterized in that at least the first axising member presses the movable member in the axial direction to prevent rattling . In the flow regulating valve according to claim 1,
The flow rate regulating valve, wherein the storage chamber is partitioned into a primary chamber opposite to the valve and a secondary chamber on the valve side with the movable member interposed therebetween, and the secondary chamber is filled with a compressed fluid.

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