Flow control valve

Abstract

Flow control valve (10), comprising: a housing formed with a first axial opening (14), a second axial opening having an inlet (18) and a valve bore (13) communicating with and coaxial with the first and second axial openings, and with an outlet channel having an outlet (19) and a connecting opening connecting a side surface of the first axial opening (14) to the outflow channel; a needle valve (60) adapted to move in the first axial opening (14) relative to a valve seat (16) located between the first axial opening (14) and the valve bore (13); and a flow rate adjustment knob (40) attached to the proximal end of the needle valve (60) extending from the housing (10); wherein the needle valve (60) is moved relative to the valve seat (16) by rotating the flow rate adjustment knob (40) to thereby regulate the flow rate of the fluid flowing through the inlet (18) to the outlet channel through the second axial opening and the valve bore (13); wherein a first valve body (67) is arranged at the front end of the needle valve (60) and a second valve body (66) extends from the end surface of the first valve body (67), wherein the first valve body (67) and the second valve body (66) are in a truncated conical shape extending in the closing direction of the flow regulating valve (10), and wherein the cross section of the first valve body (67) is larger than the cross section of the second valve body (66), the axial length of the first valve body (67) is equal to an inner diameter of the communication opening; and wherein at the time of closing the flow regulating valve (10), the end surface (67a) of the first valve body (67) abuts the valve seat (16) located between the first axial opening (14) and the valve bore (13), the side surface of the first valve body (67) faces the connection opening, and the second valve body (66) is inserted into the valve bore (13), wherein the end surface (67a) of the first valve body (67) is larger than a cross section of the valve bore (13) and wherein the axial length of the second valve body (66) is longer than the valve bore (13).

Description

Technical area

[0001] This invention relates to a flow regulating valve for regulating a flow rate by moving a needle valve relative to a valve seat. State of the art

[0002] A flow control valve is now used in various fields. Fig. Fig. 6a shows a partially enlarged view of a flow regulating valve similar to the one disclosed in the prior art, such as Japanese Unexamined Patent Publication JP H11-230407 A. As in Fig. As shown in Figure 6a, the housing 110 of this flow control valve 100 is formed with an inlet 180 and an outlet 190, which are connected to each other by a valve bore 130 and an axial opening 140. As shown, the valve bore 130 is narrower than the axial opening 140. A needle valve 600 is inserted into the axial opening 140, with a substantially conical valve body 650 disposed at the forward end of the needle valve 600. As shown, the proximal end of the valve body 650 and the forward end of the needle valve 600 coincide. In this flow control valve 100, the flow rate, or flow velocity, of fluid flowing through the valve bore 130 can be regulated by moving the needle valve 600 in the opening (upward) direction.

[0003] Fig. Figure 6b is a diagram showing the relationship between the position of the Fig. 6a shows the valve body of the flow control valve and the flow velocity. In Fig. 6b, the ordinate represents the flow velocity Q of fluid flowing through the outlet 190, and the abscissa represents the distance x covered by the valve body 650 in the opening direction from the position thereof in a closed state. Since the valve body 650 of the needle valve 600 is substantially conical, if the needle valve 600 of the flow regulating valve 100 is in the closed state, by moving in the opening direction, as shown by the solid line Y1 in Fig. 6b, the flow velocity Q increases exponentially. Upon movement of the valve body 650 into the axial opening 140 (x = x1), the flow velocity Q is kept substantially constant, as indicated by the solid line Y2.

[0004] The prior art provides a flow control valve with a different shape of a valve body. Fig. Figure 7 is a partially enlarged view of another conventional flow control valve. In Fig. 7a, a frustoconical valve body 660 is narrower in width than the needle valve 600 and extends from the forward end of the needle valve 600. When the flow control valve 100' is in a closed state, the end surface 665 of the needle valve 600 abuts the valve seat 160 disposed between the axial opening 140 and the valve bore 130, so that the valve body 660 is inserted into the valve bore 130.

[0005] Fig. 7b shows a diagram similar to Fig. 6b, which shows the relationship between the position of the valve body of the Fig. 7a and the flow rate. In this flow rate regulation valve 100', if the needle valve 600 of the flow rate regulation valve 110' is in a closed state, the flow rate Q will increase, as indicated by the solid line Y3, while the small flow rate is maintained linearly. However, since the gap between the valve bore 130 and the valve body 660 is comparatively small, the flow rate only increases slightly, with the fluid flowing in only a very small amount. Once the forward end 661 of the valve body 660 has been moved completely into the axial opening 140, as indicated by the solid line Y4 in Fig. As shown in Figure 7b, the flow velocity Q increases noticeably from the point with the distance x equal to x2.

[0006] Since the conical portion of the valve body 660 also widens relatively gradually, a flow velocity with comparatively better linearity can be obtained in the region where the distance x is smaller than x2. However, if the flow velocity is increased by moving the valve body 660 within the valve bore 130 in such a way that the valve body 660 remains in the valve bore 130, the mild taper of the flow control valve requires a considerably long valve body 660 to obtain the appropriate flow velocity. In such a case, the flow control valve itself will increase in size, and consequently, it is impossible to obtain a comparatively compact flow control valve.

[0007] If, as described above, the flow control valve 100 having the valve body 650 with a sharply spreading conical portion as shown in Fig. 6, it is difficult to regulate the flow rate while maintaining the small flow rate range linear at the time of opening / closing. If the flow regulating valve 100' is used, which, as shown in Fig. 7, the valve body 660 has a weakly scattering conical section, the flow regulation range is narrower and it is difficult to regulate the flow velocity in its magnitude. If it is desirable to adjust the flow regulation range for the Fig. 7, then it is necessary that the conical portion, ie the valve body 660 itself, is very long, which leads to an increasing size of the flow regulating valve.

[0008] In recent years, flow control valves 100, 100' have been widely used as control valves in semiconductor manufacturing apparatus. The yield achieved by the semiconductor device has been adversely affected by the instability of the flow rate of a chemical liquid, such as an etching solution or a developer, which is adjusted by the flow control valves 100, 100'. Since the demand for a reduced size of a semiconductor manufacturing apparatus is high, a compact flow control valve is also desirable. Also, the specification of each flow control valve requires the widest possible flow rate range.

[0009] Document JP 2005-155878 A provides a flow rate adjustment valve capable of finely adjusting a flow rate within a wide flow rate range, maintaining the flow rate adjustment characteristic stably over a long period of time, and being miniaturized. It discloses a main body having a valve seat surface formed on the bottom surface of the valve chamber provided in the upper portion, a first channel communicating with the communication port provided in the center of the valve seat surface, and a second channel communicating with the valve chamber, and a stem that can be inserted into the communication port by the forward and backward movement in the axial direction and protrudes from the center of the fluid contact surface.and wherein the valve seat surface can be brought into contact with and separated from the first valve body in the radial direction, wherein a second valve body having an annular rib formed at one position and a diaphragm integrally provided with a thin film portion formed continuously from the second valve body in a radial direction.,

[0010] Document US 3,428,291 A discloses a metering valve comprising a base part through which a fluid passage extends, an elongated bore in the base part which opens upwards and intersects the fluid passage at its lower end, the lower end of the bore having a small internal diameter relative to the upper end of the bore and forming a shoulder with the upper end of the bore, a cap having a central bore coaxial with the elongated bore and abutting the base part; means for securing the cap to the base part; a one-piece stem reciprocally received in the bore in the cap, the lower end of the stem being needle-like and extending into the lower end of the elongated bore in the base part; a bellows surrounding part of the stem and having an upper end secured to the stem; means for securing the lower end of the bellows to the base part;an opening in the upper end of the hood which is coaxial with the aforementioned bores, the upper end of the stem extending through the opening in the hood, threaded means on the upper end of the stem, threaded means on the upper end of the hood, the pitch of the hood threads being different from the pitch of the stem threads, an actuator which is in threaded engagement with the threaded upper end of the stem and the threads on the hood, whereby the actuator can be rotated relative to the hood and the stem.

[0011] Document US 4 077 606 A discloses several embodiments of flow control valves having a variety of unique features, including an actuating stem mounted in the valve body to protect both the stem and the valve stem, means for indicating the position of the valve stem, such as a dial indicator mounted directly on the stem or a two-stage scale mounted on the stem and the actuating stem of the valve, a stem structure that allows both sizing of the flow path and positive sealing without the use of soft seals, an adjustment structure that eliminates manufacturing tolerance problems, and an interchangeable flow control device that allows the use of a single basic valve for flow control under a variety of circumstances.Certain of the features listed above are useful in embodiments of the valve suitable for commonly known applications, and others are particularly useful in precision metering valves of the type used to accurately meter small volumes of liquid across a high pressure drop or small volumes of liquid from the atmosphere into a hard vacuum.

[0012] Document US 4 687 181 A discloses a metering valve with a one-piece valve bonnet to reduce problems resulting from overlapping tolerances. A guide member is provided on the nose of the bonnet, which cooperates with a valve body bore to ensure concentric alignment between the dispensing pin and the associated orifice. A pair of O-rings on the valve stem cooperates with the valve bonnet bore to absorb forces and significantly reduce the risk of seizure and breakage of the dispensing needle. One of the O-rings is compressed to a much greater extent than the other to achieve better alignment between the spindle and valve bonnet and to maintain a firmer feel. At the outer end of the valve spindle is a handle that receives an upper portion of the valve bonnet.

[0013] A seal is located between the handle and the top of the valve cover, limiting lateral movement between the handle and the valve stem. The packing can be selectively adjusted without changing the preset dead center position of the valve.

[0014] Document US 3 280 836 A discloses a dual pattern metering valve comprising a housing through which a fluid passage extends, the passage communicating with countersunk portions at opposite ends of the housing to thereby form an annular seating lip, inlet means communicating with one of the countersunk portions and outlet means communicating with the other of the countersunk portions, first and second elongate stem means each carrying a slender, elongate, conical needle member, the stem means being disposed in the opposite ends of the housing, the free end of each of the needle members extending through the seating lip into the passage, and means for extending and retracting each of the stem means.

[0015] Document US 3 240 230 A discloses a valve device comprising a housing having a plurality of adjacent, coaxially aligned bore sections, each successive bore section being reduced in diameter relative to the next adjacent bore section and connected thereto by generally radially extending shoulder means, a bonnet member being received and secured in the largest bore in the housing, the bonnet member having a central bore section coaxially aligned with the bore sections in the housing, an annular seating lip formed by the shoulder means and connecting the smallest diameter bore to a middle diameter bore section adjacent thereto, an elongated stem reciprocally received in the bore sections in the housing and the bonnet, a secondary sealing device,which is spaced from the seating lip and is arranged between the end of the hood part and the shoulder means connecting the largest bore section to the next adjacent bore section, the secondary sealing means being engaged with the stem and having sufficient rigidity to provide low-friction support therefor and for a primary seal and to provide a secondary seal between the stem, the housing and the hood, the housing and the hood, the stem being provided at one end with a generally conical needle element which is opposite and coaxially aligned with the smaller diameter bore section and converges in the direction of diameter reduction of the successive bore sections,wherein the diameter of the conical needle element at its smallest value is smaller than the diameter of the smaller diameter bore portion and at its largest value is larger than the diameter of the smaller diameter bore portion, wherein the stem is provided with a groove adjacent to the needle element and an O-ring, primary sealing means in the groove sealingly engaging the intermediate bore to provide a primary seal between the stem, the housing, and the hood, a pair of fluid outlet channels intersecting the smaller diameter bore portion between the primary sealing means and the seat lip, means for establishing fluid communication between the smaller diameter bore portion and a fluid inlet channel, means enclosing the intermediate diameter bore,to establish fluid communication between the inlet passage and the pair of fluid outlet passages, and means for axially extending and retracting the shaft, thereby moving a portion of the needle member between its ends into and out of substantially flush fluid-tight engagement with the annular seating lip, wherein the primary sealing means, when the needle engages the annular seating lip, is disposed between the secondary sealing means and the intersection of the outlet passages with the intermediate bore, the communication between the outlet passages being uninterrupted.

[0016] Document US 3 334 654 A discloses an actuating and reading means for a device having a body and a stem projecting outwardly from the body and provided with a thread for axial movement inward and outward with respect to the body, the means comprising: a hood extending outwardly from the body; a manually engageable knob screwed to the hood for axial movement toward and away from the body;which are operatively arranged between the knob and the shaft to connect them for simultaneous rotation causing axial movement of both while permitting relative axial movement therebetween, the block and the hood together forming a readout column, the threaded connections of the shaft and the knob having a different pitch such that upon simultaneous rotation of the knob and the shaft, the knob and the shaft have relative axial movement and the block is moved with respect to the hood to vary the length of the readout column and expose one end of the column at one end of the knob, the speed of exposure of the readout column being directly proportional to, but substantially greater than, the speed of axial movement of the shaft;

[0017] Document US 2002 / 0 100 503 A1 discloses a sanitary diaphragm valve having a generally dome-shaped diaphragm with a central projection connectable to or driven by a valve actuator. The diaphragm has an outer peripheral edge and a relatively thin land connecting the projection to the outer edge. In one embodiment, the land portion is arcuate or dome-shaped. The thinner land allows for longer diaphragm life and valve operation at higher fluid pressures. The thin land may be defined by two differently contoured surfaces, one convex and the other concave, e.g., formed by two radii. A valve body is provided having a bowl-shaped valve cavity. This valve cavity has an outer vertical edge to allow for more thorough cleaning and to eliminate entrapment areas.The valve assembly provides support surfaces for the diaphragm, reducing stress on the diaphragm, particularly at higher operating pressures. A deep bowl design is provided, in which the valve cavity is defined by a spherical, and preferably hemispherical, surface, with the cavity diameter approximately equal to the diaphragm diameter. The diaphragm for the deep bowl design has a stem tip that seals one of the valve openings radially outward. The opening may have a beveled valve seat adjacent to the opening, and the opening may be formed by a conical bore.

[0018] Document US 4 772 016 A discloses an actuator comprising a pair of arms pivotally connected at one end and a pneumatic pump interposed therebetween, activated by the relative movement of the arms. The pump consists of a cylinder pivotally connected to one arm and a rod fixedly or pivotally connected to the other arm. The rod carries a piston extending into the cylinder. The closed end of the cylinder incorporates a continuously adjustable air release valve for the controlled release of compressed air from the closed end of the cylinder when the user pivots the distal ends of the arms together. The resistance to the relative movement of the arms by the user is selected according to the user's preference by adjusting the release value. The adjustable valve has an infinite number of positions between fully closed and fully open.

[0019] Document EP 0 140 577 A2 discloses a needle valve comprising a housing having inlet means and outlet means forming a flow path, a valve seat in the flow path, a needle connected to the housing and movable toward and away from the valve seat to decrease and increase the flow through the needle valve, the needle entering the valve seat so as to physically contact the inner surface of the valve seat throughout its movement.

[0020] This invention has been accomplished in view of this situation, the object of which is to provide a compact flow regulating valve in which a fluid is supplied in a stable manner at a flow rate at which linearity is maintained from a closed state to a fully open state. Disclosure of the invention

[0021] To achieve the above-described object, according to a first embodiment of the invention, a flow regulating valve is provided, comprising a housing formed from an axial opening and a valve bore connected to the axial opening, a needle valve adapted to be moved within the axial opening relative to the valve seat disposed between the axial opening and the valve bore, and a flow rate adjusting knob mounted on the proximal end of the needle valve extending from the housing, wherein the needle valve is moved relative to the valve seat by rotating the flow rate adjusting knob, thereby regulating the flow rate of the fluid flowing through the valve bore.wherein a first valve body is arranged at the front end of the needle valve and a second valve body extends from the end surface of the first valve body, and wherein the cross section of the first valve body is larger than the cross section of the second valve body, so that at the time of closing the flow regulating valve, the end surface of the first valve body abuts the valve seat arranged between the axial opening and the valve bore, and the second valve body is inserted into the valve bore.

[0022] The flow velocity will only increase exponentially after valve opening if the first valve body is provided to abut against the valve seat, while the flow velocity will only increase after slow valve opening if the second valve body is inserted into the valve bore. On the other hand, in the first embodiment of the invention, by providing both the first valve body to abut against the valve seat and the second valve body to be inserted into the valve bore, the above-mentioned two features are combined into the small flow velocity range, wherein the flow velocity increases substantially linearly immediately after the valve opening. The flow velocity of the fluid increases substantially linearly in a more stable manner once it has increased to a certain level.Particularly, in the first embodiment, the fluid can be supplied in a stable manner with the flow velocity kept linear from a closed state to a fully open state.

[0023] According to a second embodiment of the invention, there is provided a flow regulating valve of the first embodiment, wherein the first valve body and the second valve body have a truncated cone shape extending in the closed direction of the flow regulating valve.

[0024] According to a third embodiment of the invention, there is provided a flow regulating valve of the second embodiment, wherein the angle between the side surface of the first valve body and the cross section of the needle valve is smaller than the angle between the side surface of the second valve body and the cross section of the needle valve.

[0025] Particularly in the second and third embodiments, the first and second valve bodies have a shape such that the flow velocity is relatively uniform from the small flow velocity range to the large flow velocity range, and the difference in flow velocity that varies between the small and large flow velocity ranges is eliminated. In this way, the flow velocity is easily regulated by obtaining a flow velocity that is linear over the entire range, and fluid can be supplied in a stable manner over the entire range. Incidentally, the first and second valve bodies preferably have a truncated cone shape.

[0026] According to a fourth embodiment of the invention, there is provided a flow regulating valve of any of the first to third embodiments, wherein the first valve body comprises a diaphragm attached to the inner wall of the housing.

[0027] Particularly, in the fourth embodiment, the fluid can be supplied in a stable manner with a flow rate kept linear even for a diaphragm-type needle valve.

[0028] All of the above-described embodiments share the advantage that fluid can be provided in a stable manner with a flow rate that is maintained linearly from a closed state to a fully open state.

[0029] Furthermore, the second and third embodiments have an advantage in that the difference in flow velocity at the boundary between the small and large flow velocity regions is eliminated, whereby fluid can be supplied in a stable manner with a flow velocity maintained linearly.

[0030] Furthermore, the fourth embodiment has an advantage in that fluid can be supplied in a stable manner3 with a flow rate kept linear even for a diaphragm-type needle valve.

[0031] The above and other objects, features and advantages will become apparent from the detailed description of typical embodiments of the invention taken in conjunction with the accompanying drawings. Short description of the drawings Fig. 1a shows a front view of a flow regulating valve according to this invention. Fig. Figure 1b shows a side sectional view of the flow regulating valve according to the invention. Fig. Figure 2 is a schematic diagram showing an enlarged view of the valve body immediately after the valve is opened. Fig. Figure 3 is a schematic diagram showing an enlarged view of the valve body. Fig. 4 is a diagram showing the relationship between the position of the valve body and the flow velocity in the flow regulating valve according to the invention. Fig. 5 illustrates a front view of the flow regulating valve according to another embodiment of the invention. Fig. Figure 6a shows a partially enlarged view of a conventional flow control valve. Fig. Figure 6b is a diagram showing the relationship between the position of the valve body and the flow velocity in the flow regulating valve. Fig. Figure 7a shows a partially enlarged view of another conventional flow control valve. Fig. Figure 7b is a diagram showing the relationship between the position of the valve body and the flow velocity in the Fig. 7a shows the flow control valve. Best mode for carrying out the invention

[0032] The embodiments of the invention are described below with reference to the accompanying drawings. In the drawings, similar component elements are designated by the same reference numerals. To facilitate understanding, the scale of these drawings has been appropriately changed.

[0033] Fig. 1a shows a front view of a flow regulating valve according to an embodiment of the invention, and Fig. 1b shows a side sectional view of the flow control valve according to an embodiment of the invention. As shown in these drawings, the housing of the flow control valve 10 according to the invention is composed of a lower portion 11 and an upper portion 20. The lower portion 11 of the housing is formed with an inlet 18 and an outlet 19. The inlet 18 and the outlet 19 communicate with each other in the lower portion 11 through a valve bore 13 and an axial opening 14, described below.

[0034] As from the Fig. 1b, a lower sleeve 12, which is narrower than the lower portion 11, is arranged in the lower portion 11 of the housing. In the upper portion 20 of the housing, an upper sleeve 22 is formed, which is adapted to engage with the lower sleeve 12. As shown, the upper portion 20 and the lower portion 11 of the housing are screwed together by threads formed on the outer surface of the lower sleeve 12 and the inner surface of the upper sleeve 22, respectively. The upper portion 20 is fixed to the lower portion 11 by a spring roller pin 15, which functions as a fastening pin. A spring roller pin 15, which connects the upper sleeve 22 of the upper portion 20 and the lower sleeve 12 of the lower portion 11, is normally arranged at a position that is not accessible from the outside.Once the lower portion 11 and the upper portion 20 of the housing are arranged, a common axial opening 14 is formed in the housing, into which the larger part of the needle valve 60 is inserted. Incidentally, the upper portion 20 and the lower portion 11 may be secured by means other than a spring roller pin 15.

[0035] According to the Fig. 1a, Fig. In the embodiment shown in Figure 1b, the upper portion 20 of the housing can serve as a closure adjustment element for adjusting the closed state between the upper portion 20 and the needle valve 60. However, the upper portion 20 is normally fixed to the lower portion 11 by the spring roller pin 15, as shown. Specifically, according to one embodiment of the invention, the initial value of the closed state preset by the manufacturer is maintained, thereby maintaining the closed state between the upper portion 20 and the needle valve 6 even if a user or the like touches the upper portion 20 of the housing. In particular, when the conventional flow control valve is mounted on a panel, it is necessary to remove the closure nut to determine the closed state, and thereby changing the initial value of the closed state.According to this invention, it is not necessary for the upper portion 20, which functions as a closure adjusting member, to be removed at the time of attaching the panel, thereby keeping the closed state unchanged.

[0036] As shown, a cylindrical extension 21 extends from the upper portion 20, narrower than the upper portion 20 of the housing. Furthermore, the needle valve 60 extends from above the extension 21. The outer surface of the extension 21 is formed with a thread, to which the extension 21 of the panel nut 30 is threaded. This panel nut 30 is used to attach the flow control valve 10 to a panel (not shown). Typically, the length of the extension 21 is greater than the sum of the thickness of the panel and the thickness of the panel nut 30.

[0037] Furthermore, as in Fig. 1b, a flow rate adjustment knob 40 is attached to the proximal end of the needle valve 60. The proximal end of the needle valve 60 is inserted into the opening formed in the flow rate adjustment knob 40, and the flow rate adjustment knob 40 is fixed to the needle valve 60 by a fixing screw 41. As also shown in Fig. 1a, Fig. 1b, a lock nut 35, described below, is screwed onto the thread 61 between the flow rate adjustment knob 40 and the panel nut 30. As shown, the size of the lock nut 35 is larger than the size of the flow rate adjustment knob 40 and the panel nut 30. Furthermore, to allow a user to easily grip the flow rate adjustment knob 40, the lock nut 35, and the panel nut 30, respectively, the peripheral surfaces of the flow rate adjustment knob 40, the lock nut 35, and the panel nut 30 are knurled.

[0038] As also in Fig. As shown in Figure 1b, the needle valve 60 is composed of a first portion 64 and a second portion 65, including a valve body having a first valve body 67 and a second valve body 66. The first valve body 67 has a wide portion 62 that couples to the second portion, and a thread 63 is formed on the peripheral surface of the wide portion 62. As shown, the thread 63 is screwed into the threaded inner surface of the extension 21 of the upper portion 20. In the presence of these threads, the needle valve 60 can be moved in an axial direction by rotating the flow rate adjustment knob 40.

[0039] The lower portion 11 of the housing is formed with a narrow valve bore 13 connected to the inlet 18. As shown, the valve bore 13 and the axial opening 14 are concentric, with the valve bore 13 being narrower than the axial opening 14. Furthermore, a valve seat 16 is formed between the axial opening 14 and the valve bore 13, as shown.

[0040] Fig. Figure 2 is a schematic diagram showing an enlarged view of the valve body immediately after the valve is opened. To simplify the explanation, it should be noted that the upper portion 20 of the housing, etc., is not shown in Fig. 2 and Fig. 3 (described below). As shown in Fig. As shown in Figure 2, the first valve body 67 is substantially truncated conically in shape and extends in a downwardly tapered manner in the closing direction of the valve. The first valve body 67 extends from the end of the second portion 65, whereby one end of the first valve body 67 coincides with the end of the second portion 65. The end surface 67a of the first valve body 67 is also larger than the cross-sectional area of ​​the valve bore 13.

[0041] Furthermore, the truncated cone-shaped second valve body 66 extends from the end surface 67a of the first valve body 67 in a downwardly tapered manner in the closing direction of the valve. As shown, the second valve body 66 is narrower than the end surface 67a of the first valve body 67. The axial length of the second valve body 66 is longer than the valve bore 13 and the axial length of the first valve body 67. As further shown in Fig. 2, the proximal end of the second valve body 66 is slightly narrower than the transverse or cross-sectional area of ​​the valve bore 13. The angle A1 between the proximal end of the first valve body 67 and the cross-section of the second partial area 65 is also smaller according to this invention than the angle A2 between the proximal end of the second valve body 66 and the cross-section of the second partial area 65.

[0042] According to this invention, the end surface 66a of the second valve body 66 remains within the valve bore 13 and is never moved to the axial opening 14 if the needle valve 60 is fully opened. Fig. 3 shows a schematic diagram similar to Fig. 2, which shows an enlarged view of the fully open needle valve 60. In Fig. 3, the end surface 66a of the second valve body 66 is arranged slightly lower than the valve seat 16. In the Fig. In the case shown in Figure 3, fluid flows through the gap between the valve bore 13 and the second valve body 66 into the axial opening 14 and flows out via the outlet 19. Conversely, if the end surface 66a of the second valve body 66 is moved toward the axial opening 14 beyond the valve bore 13, the flow velocity would instantly increase and become uncontrollable. However, according to this invention, the end surface 66a of the second valve body 66 is located within the valve bore 13 when the valve is fully open, and thus the flow velocity can be controlled.

[0043] With further reference to Fig. 1a, Fig. 1b, the flow control valve 10 is in a closed state, and consequently the end surface 67a of the first valve body 67 of the second section 65 abuts against the valve seat 16, and the second valve body 66 of the second section 65 is inserted into the valve bore 13.

[0044] In Fig. 1b, a first seal 71, essentially truncated cone-shaped, is also mounted on the ramp surface or slope 14a of the axial opening 14 around the second portion 65 below the wide portion 62. Furthermore, a second seal 72 with a flange extending between the lower portion 11 and the upper portion 20 is arranged above the first seal 71. The first seal 71 and the second seal 72 can be installed as a single element.

[0045] As described above, the lock nut 35 is screwed onto the thread 61 of the first portion 64 of the needle valve 60. The lock nut 35 serves to limit the rotation of the flow rate adjustment knob 40. According to the Fig. 1a, Fig. In the embodiment shown in Figure 1b, the lock nut 35 secures the flow rate adjustment knob 40 so as not to be rotated if it is disposed in a position adjacent to the extension 21 of the upper portion 20. Therefore, under this condition, even if the flow rate adjustment knob 40 is touched by a user or the like, it would not be rotated, thus keeping the flow rate of the flow control valve 10 unchanged. If a gap larger than a certain size is formed between the lock nut 35 and the extension 21 by loosening the lock nut 35, the flow rate adjustment knob 40 can be rotated, so that the flow rate of the flow control valve 10 can be controlled.

[0046] When the flow control valve 10 is mounted on a panel (not shown), the flow rate adjustment knob 40, the lock nut 35, and the panel nut 30 are removed in this order. Subsequently, the housing extension 21 is inserted into the opening of the panel (not shown). The panel opening corresponds to the size of the extension 21, and the panel stops before the upper portion 20. Then, the panel nut 30 is screwed onto the extension 21 to secure the flow control valve 10 to the panel. After that, the lock nut 35 and the flow rate adjustment knob 40 are reattached. As described above, according to one embodiment of the invention, at the time of mounting the flow control valve 10, it is not necessary to remove the upper portion 20 of the housing, which functions as a closure adjustment member.Therefore, the closed state between the needle valve 60 and the housing can be maintained during shipping.

[0047] During operation of the flow control valve 10, according to one embodiment of the invention, a gap larger than a certain size is formed between the lock nut 35 and the extension 21 of the upper portion 20 by loosening the lock nut 35, after which the needle valve 60 is moved upwards by turning the flow rate adjustment knob 40. As shown in Fig. 2, immediately after opening the flow control valve 10, a comparatively small amount of fluid flows in from the inlet 18, flows further into the axial opening through the gap between the second valve body 66 and the valve bore 13 and flows out through the outlet 19.

[0048] Fig. Figure 4 is a diagram showing the relationship between the position of the valve body and the flow velocity in the flow control valve according to the invention. Fig. 4, the ordinate represents the flow velocity Q of the fluid flowing out of the outlet 19, and the abscissa represents the distance x between the end surface 67a of the first valve body 67 and the valve seat 16. As described above, at the time of closing the flow regulating valve 10, the end surface 67a of the first valve body 67 and the valve seat 16 may be in contact with each other, and thus the distance x can be considered equivalent to the distance covered by the needle valve 60 from the closed position to the end of the needle valve in the opening direction.

[0049] As in Fig. 4, the relationship between the distance x covered by the valve body and the flow velocity Q is substantially linear in the small flow velocity range Z1 in which the flow velocity is comparatively small after opening the flow regulating valve 10. As shown in Fig. 6 with respect to an explanation of the prior art, a case in which the needle valve 600 has only a substantially pyramidal valve body 650 may correspond to a case in which the needle valve 60 according to the invention has only the first valve body 67. Assuming that the needle valve 60 according to the invention has only the first valve body 67, the flow velocity Q increases with respect to the distance x in the manner described above with reference to Fig. 6 described, comparatively small flow velocity range increases exponentially.

[0050] If, as in Fig. 7, the needle valve 600 comprises only one valve body 660 which is narrower than the valve body 650, this may, on the other hand, with regard to an explanation of the prior art, correspond to a case in which the needle valve 60 according to the invention only comprises the second valve body 66. Assuming that the needle valve 60 according to the invention only comprises the second valve body 66, consequently, as above with regard to Fig. 7, the flow velocity Q increases comparatively slowly with respect to the distance x in the comparatively small flow velocity range. Consequently, on the one hand, it is difficult to ensure the required flow velocity, while on the other hand, a large difference or step in the change of a flow velocity is formed at the boundary (x = x2) (See Fig. 7b).

[0051] In contrast, the needle valve 60 according to the invention comprises both a first valve body 67 corresponding to the valve body 650 and a second valve body 66 corresponding to the valve body 660. In the small flow velocity range Z1 of the flow regulating valve 10 according to the invention, the relationship therefore represents a combination of those in Fig. 6b and Fig. 7b. In the small flow velocity range Z1, a substantially linear relationship is obtained according to the invention, which represents a mixture of the two ratios (see Fig. 4). In particular, Fig. 6b, assuming that the straight line connecting the flow velocity at the maximum distance and the origin is a straight line B1, the area A1 is defined by the solid line Y1, where the line segment x = x1 and the straight line B1 represents the flow velocity excess provided over the straight line B1. Similarly, in Fig. 7b, assuming that the straight line connecting the flow velocity at the greatest distance and the origin is a straight line B2, then the area A3 is defined by the solid line Y3, the line segment x = x2 and the straight line B2 represents the flow velocity reduction below the supply amount shown by the straight line B2.

[0052] In particular, according to the invention, the area A1, which represents the oversupply, is supplied by the area A3 of low supply, so that a substantially linear relationship between distance x and flow velocity Q is obtained in the small flow velocity range Z1 (see Fig. 4). In this area, the flow rate changes according to the rotation of the flow rate adjustment knob 40. Incidentally, the solid line Y1 in Fig. 6b is a curved line, and therefore the relationship in the small flow velocity range Z1 is not a true straight line. Nevertheless, the essentially straight relationship shown in Fig. 4 is preserved.

[0053] According to the invention, the small flow velocity region Z1 transfers to the large flow velocity region Z2, assuming that the needle valve 60 is moved further and that the distance x exceeds a certain distance xa. In this large flow velocity region Z2, the concept similar to that mentioned above also applies. In particular, the lower supply region A4, which is defined by the solid line Y4, the line segment x = x2 and the straight line B2, which is Fig. 7b, is supplied by the oversupply area A2 defined by the solid line Y2, the line segment x = x1 and the straight line B1, which is shown in Fig. 6b. As shown in Fig. 4, therefore, the linear relationship between the flow velocity Q and the distance x is also obtained in the large flow velocity range Z2.

[0054] As described above, according to the present invention, a substantially linear relationship exists between the flow velocity Q and the distance x in both the small flow velocity range Z1 and the large flow velocity range Z2, i.e., across the entire range. Therefore, fluid can be supplied stably at a flow velocity that maintains linearity. Therefore, the yield of manufactured semiconductor devices is not reduced even when the flow rate regulating valve 10 according to the present invention is used in a semiconductor manufacturing apparatus.

[0055] Furthermore, as described above, the first valve body 67 and the second valve body 66 are in the frustoconical shape extending in the valve closing direction. The angle A1 between the proximal end of the first valve body 67 and the cross section of the second portion 65 is smaller than the angle A2 between the proximal end of the second valve body 66 and the cross section of the second portion 65, and the axial length of the first valve body 67 is smaller than the axial length of the second valve body 66. The angle A1 between the proximal end of the first valve body 67 and the cross section of the second portion 65 is approximately 80° according to the preferred embodiment shown, and the angle A2 between the proximal end of the second valve body 66 and the cross section of the second portion 65 is approximately 85°.Furthermore, the axial length of the second valve body 66 is approximately twice the axial length of the first valve body 67.

[0056] The angles A1, A2 and the length of the first valve body 67 and the second valve body 66 are selected such that the flow velocity Q of the flow control valve 10 assumes a substantially equal value when transferring from the small flow velocity range Z1 to the large flow velocity range Z2, that is, the value Q1 immediately before transfer and the value Q2 immediately after transfer are substantially equal to each other. Therefore, according to the present invention, the flow velocity is transferred from the small flow velocity range Z1 to the large flow velocity range Z2 relatively smoothly without causing any step or difference in the flow velocity change between the small flow velocity range Z1 and the large flow velocity range Z2.Therefore, even in the case where the flow velocity is supplied in the range around the range boundary (x = xa) between the small flow velocity range Z1 and the flow velocity range Z2, the flow velocity changes only by an amount corresponding to the rotation of the flow velocity adjusting knob 40, and therefore the fluid can be supplied at a stable flow velocity.

[0057] Although the illustrated embodiment includes the cylindrical needle valve 60, the frustoconical first valve body 67, and the second valve body 66, the shapes of the cylindrical needle valve 60, the frustoconical first valve body 67, and the second valve body 66 are not limited to those shown in the embodiment. In particular, the axial opening 15 with a rectangular cross-section, the needle valve 60 with a corresponding rectangular cross-section, and the first valve body 67 and the second valve body 66 in the shape of a truncated pyramid are also clearly within the scope of this invention.

[0058] Fig. Fig. 5 is a front view of the flow control valve according to another embodiment of the invention. The same reference numerals listed above denote the same component elements, and therefore, the already explained component elements will not be explained again. The lower portion 11 of the flow control valve 10', which in Fig. 5, comprises a portion 11a screwed onto the upper portion 20, and a portion 11b formed with the inlet 18 and the outlet 19. The portion 11a is formed with an upper chamber 114a, and the portion 11b with a lower chamber 114b. The upper and lower chambers 114a, 114b are each formed concentrically with the valve bore 13 and the axial opening 14 and have a larger cross-section than the axial opening 14. The portion 11b is formed with a path 119 to define a connection between the lower chamber 114b and the outlet 19.

[0059] The second portion 65 of the needle valve 60 further comprises an upper portion 65a, which is connected to the upper portion 64, and a lower portion 65b, which has the first valve body 67 and the second valve body 66. The upper portion 65a and the lower portion 65b are connected to each other in the same manner as the first portion 64 and the second portion 65, as described above with reference to Fig. 1. Incidentally, the upper portion 65a and the lower portion 65b may be joined to each other by other methods or may be integrally formed with each other.

[0060] The body of the lower portion 65b further comprises, as shown in Fig.5, a diaphragm 82 is shown. The edge 83 of the diaphragm 82 is disposed in a recess formed in the portion 11a and the portion 11b such that the diaphragm 82 is supported between the upper chamber 114a of the portion 11a and the lower chamber 114b of the portion 11b. The diaphragm 82 is itself hermetic, and therefore the upper chamber 114a and the lower chamber 114b are sealably separated from each other by the diaphragm 82. The second valve body 66 further extends axially from the end surface 67a of the first valve body 67. The first valve body 67 and the second valve body 66 are shaped similarly to those described above. The first valve body 67 and the second valve body 66 may be formed integrally with the diaphragm 82.

[0061] When the needle valve 60 is moved in an axial direction when the flow control valve 10' is in operation, fluid flows into the lower chamber 114b under the diaphragm 82 through the gap between the second valve body 66 and the valve bore 13, and then flows out from the path 119 through the outlet 19. The diaphragm 82 shown prevents the fluid flowing in through the inlet 18 from flowing between the upper portion 65a and the axial opening 14, while at the same time allowing fine adjustment of the flow rate. Likewise, in this embodiment, with the diaphragm 82 connected to the first valve body 67 and the second valve body 66, as in the previously described embodiment, the fluid can apparently be supplied in a stable manner at a flow rate that maintains linearity from the closed state to the fully open state.Furthermore, although not shown in the drawings, what is called the air-operated type device in which a portion of the needle valve with the diaphragm 82 is inserted into a spring is included within the scope of this invention.

[0062] This invention is explained above with reference to typical embodiments thereof, and it will be apparent to those skilled in the art that the above-mentioned changes and various other modifications, omissions and additions can be made without departing from the scope or spirit of the invention.

Claims

[1] Flow control valve (10) comprising: a housing formed with a first axial opening (14), a second axial opening having an inlet (18) and a valve bore (13) communicating with and coaxial with the first and second axial openings, and with an outlet channel having an outlet (19) and a connecting opening connecting a side surface of the first axial opening (14) to the outflow channel; a needle valve (60) adapted to move in the first axial opening (14) relative to a valve seat (16) located between the first axial opening (14) and the valve bore (13); and a flow rate adjustment knob (40) attached to the proximal end of the needle valve (60) extending from the housing (10); wherein the needle valve (60) is moved relative to the valve seat (16) by rotating the flow rate adjustment knob (40) to thereby regulate the flow rate of the fluid flowing through the inlet (18) to the outlet channel through the second axial opening and the valve bore (13); wherein a first valve body (67) is arranged at the front end of the needle valve (60) and a second valve body (66) extends from the end surface of the first valve body (67), wherein the first valve body (67) and the second valve body (66) are in a truncated conical shape extending in the closing direction of the flow regulating valve (10), and wherein the cross section of the first valve body (67) is larger than the cross section of the second valve body (66), the axial length of the first valve body (67) is equal to an inner diameter of the communication opening; and wherein at the time of closing the flow regulating valve (10), the end surface (67a) of the first valve body (67) abuts the valve seat (16) located between the first axial opening (14) and the valve bore (13), the side surface of the first valve body (67) faces the connection opening, and the second valve body (66) is inserted into the valve bore (13), wherein the end surface (67a) of the first valve body (67) is larger than a cross section of the valve bore (13) and wherein the axial length of the second valve body (66) is longer than the valve bore (13). [2] Flow regulating valve (10) according to claim 1, wherein the angle between the side surface of the first valve body (67) and the cross section of the needle valve (60) is smaller than the angle between the side surface of the second valve body (66) and the cross section of the needle valve (60). [3] Flow control valve (10) according to one of claims 1 to 2, wherein the first valve body (67) comprises a diaphragm fixed to the inner wall of the housing.

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