Abstract:
An in-line flow control component includes a body having an inlet and an outlet that are substantially coaxial with a tube extending through the body. The tube forms a flow path between the inlet and the outlet, and one end of the tube sealingly engages a valve seat for controlling fluid flow between the inlet and outlet. First and second diaphragms each have an opening sealingly secured about an outer periphery of the tube and an outer peripheral portion sealed to the body. The diaphragms selectively move the tube between open and closed positions in response to force acting on the diaphragms. The force is provided by either a mechanical mechanism (toggle, wedge member, threaded adjustment knob, etc.) or fluid pressure introduced between the diaphragms. The diaphragms may be similarly or differently dimensioned. Plural flow control components may be assembled in end-to-end sealed relationship.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This disclosure relates to commonly-owned, U.S. provisional application Ser. Nos. 61/154,534, filed 23 Feb. 2009 and 61/172,505, filed 24 Apr. 2009, the disclosures of which are expressly incorporated herein by reference. 
    
    
     FIELD OF THE DISCLOSURE 
     This disclosure relates in general to flow control components such as valves, fittings and regulators used in fluid systems, and more particularly, the disclosure relates to gas distribution systems for use in high purity fluid systems and corrosive fluid systems used to manufacture semiconductor wafers. 
     BACKGROUND OF THE DISCLOSURE 
     To manufacture semiconductors the industry uses a variety of high purity gases. These gases are controlled by systems made up of high purity valves, regulators, filters and other components. These components are connected together by either high purity metal seal fittings, by tube welding, or by bolting the components to manifolds using high purity metal seals. These connections are undesirable in most applications because they add additional time, cost and add unnecessary space between components. 
     SUMMARY OF THE DISCLOSURE 
     An in-line flow control component includes a body having an inlet and an outlet substantially coaxial with a tube extending through the body. The tube forms a flow path between the inlet and the outlet, one end of the tube sealingly engaging a valve seat for controlling fluid flow between the inlet and outlet. A first diaphragm has an opening sealingly secured to an outer periphery of the tube and sealed about an outer peripheral portion to the body. The first diaphragm selectively moves the tube between open and closed positions in response to force acting on the first diaphragm. 
     The in-line flow control component further includes a second diaphragm having an opening sealingly secured to an outer periphery of the tube, and sealed about an outer peripheral portion to the body at a location spaced from the first diaphragm. 
     The first and second diaphragms are axially spaced along the tube, and a space therebetween is sealed from fluid flowing through the tube. 
     In one preferred embodiment, a mechanical mechanism includes a wedge assembly for selectively moving the tube. 
     In another embodiment, fluid pressure is introduced to an area between the first and second diaphragms for selectively moving the tube. 
     A spring urges the tube toward one of an open or closed position. 
     The first and second diaphragms are substantially the same dimension, or in an alternate arrangement are different dimensions and thereby a greater force results on the diaphragm with the larger surface area and moves the tube. 
     Hence, a modular gas system that does not require high purity metal seal fittings, tube to tube welding, or expensive manifolds would be very desirable. This disclosure shows how this can be accomplished if the various components are redesigned to an in-line flow path configuration. This configuration allows the components to be coupled together in a fashion that not only eliminates the fittings, welding, or manifolds but in most situations will eliminate the inlet and outlet housings of the components as well. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A, 2A, 3A, 4A and 5A  show examples of existing high purity flow components. 
         FIGS. 2B-2J, 3B-3J, 4B-4G, 5B-5Q, 6, 7A-7E, 8A -E, and  9  show examples of high purity in-line flow path components. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     What is common in the designs of  FIGS. 1A, 2A, 3A, 4A and 5A  is that these known embodiments have a body with right angle flow paths and use a single diaphragm. This diaphragm is secured to the body along a circumference of the diaphragm so that the diaphragm contains fluid within the component. The diaphragm also provides a flexible member or means to control a valve mechanism inside the components body of the component with a mechanical member or means located outside the body of the component. 
     What is common in the designs of  FIGS. 2B-2J, 3B-3J, 4B-4G, 5B-5Q, 6, 7A-7E, 8A -E, and  9  is the use of two diaphragms with holes through the center. These diaphragms are centered in the body, are positioned perpendicular to the flow path with their through holes aligned, and there is a space between them. A tube is welded between the holes in the diaphragms making a leak tight passageway through the center of the diaphragms. These diaphragms are clamped between the body parts at the outer circumference of the diaphragms and the diaphragms can flex in a parallel motion allowing the center flow tube to move back and forth in a lateral direction. A flat lateral force spring is used to urge the tube in the desired direction. A mechanism to adjust or shut off flow is located at one end of the flow tube. When this mechanism is pressed against a valve seat, flow through the component is stopped. The diaphragms have a soft metal or plastic injection molded around the circumference to make a seal to the body parts. In these drawings the seams between body parts will be welded creating a high integrity leak tight system. The body parts could also be bolted or screwed together as will be appreciated by one skilled in the art. 
     Toggle Valve 
       FIG. 1A  shows a typical high purity toggle valve. A spring and toggle stem arrangement exterior to the flow path provide the mechanical force to push or release the diaphragm against the valve seat. High purity fittings are welded to the body to connect the valve to another component or fluid source. 
       FIGS. 1B-G  show a high purity toggle valve  100  with an in-line flow path, i.e, a first opening or an inlet  102  and a second opening or outlet  104  in body portions  106   a ,  106   b  are aligned along a common longitudinal axis on opposite ends of a central body portion  106   c  and the fluid passes through the body  106  near or adjacent the longitudinal axis. In a space  110  in body portion  106   c  between axially spaced diaphragms  112 ,  114  a toggle stem  120 , spring  122  and wedge mechanism  124  provide an actuating assembly  130  or to flex the substantially same-sized diaphragms  112 ,  114  and to move hollow tube  132  that is connected to move with the diaphragms in a lateral direction pushing shut off seal  134  against seat  136 . Thus, a passage  138  through the tube is in constant communication with opening(s)  140  that communicate through the tube wall at a location between the seal  134  and the first diaphragm  112 . A flat lateral force spring  150  is located adjacent the other end of the tube and urges the seal  134  away from the seat  132  so when the toggle lever  120  is lifted the valve  100  will open and inlet  102  is in fluid communication with outlet  104  via the tube  132 . When the lever is actuated or depressed, the seal is urged toward the valve seat  132  and the force of the flat spring  150  is overcome thereby closing communication between the inlet and outlet. 
     Advantageously, the actuating assembly  130 , comprised of a lower portion of the toggle stem  120 , the spring  122 , and the wedge mechanism  124 , is located in a sealed location between the diaphragms  112 ,  114 . The wedge mechanism includes two components in this embodiment of  FIGS. 1B-1D , namely, a first wedge component  124   a  that is generally shaped as a partial conical member about the tube  132  and a second wedge component  124   b  extending from a lower portion of the toggle stem  120  for engagement with the first wedge component. The relative sliding engagement of these first and second wedge components relative to one another in response to movement of the toggle, laterally moves the tube and diaphragms located adjacent opposite ends of the tube between open and closed positions. 
       FIGS. 1E-G  show another way of creating the lateral movement necessary to open and close the valve by using a three wedged washer design  124   c ,  124   d ,  124   e . The center washer  124   e  is moved in a vertical motion forcing the two outer washers  124   c ,  124   d  to move in a lateral or horizontal direction. In substantially all other respects, the embodiment of  FIGS. 1E-1G  is structurally and functionally similar to  FIGS. 1B-1D . 
     Pneumatic Valve 
       FIG. 2A  shows a typical high purity pneumatic valve. A spring loaded plunger pushes the diaphragm against a valve seat. The plunger is urged away from the valve seat by pneumatic driven pistons. 
       FIGS. 2B-D  shows one version of a high purity in-line flow path pneumatic valve  200 . Where possible, like elements will be identified by like reference numerals in the  200  series. Like the toggle valve  100  above there is a tube  232  which has diaphragms  212 ,  214  with holes through the center welded to each end of the tube. Unlike the toggle valve, this pneumatic valve design has one diaphragm  214  with a larger outer diameter than the other diaphragm  212  and therefore the second diaphragm  214  has a larger surface area. The flat lateral force spring  250  is used to urge the flow tube  232  and valve shut off seal  234  to the closed position. A flow passage  252  through the outer body housing is located between the diaphragms to provide pneumatic pressure. When the space or  210  area between the diaphragms  212 ,  214  is pressurized, the force created on the larger diaphragm  214  is greater than that on the smaller diaphragm  212  causing the flow tube  232  and valve  234  to shift to the open position. A normally open valve could be made by locating the valve mechanism to the other end of the tube. 
       FIGS. 2E-G  shows another version of a high purity in-line flow path pneumatic valve  200  that might be used in high pressure systems. In this design the two diaphragms  212 ,  214  can be of substantially equal diameter. Between the diaphragms one or more pistons  254  are slid over the flow tube and a stationary plate  256  is positioned adjacent to each piston  254 . The pistons  254  and stationary plates  256  have o-ring seals  258  on the inner and outer diameters. A flow passage  252   a ,  252   b  through the body  206  is located between each piston and stationary plate. A mechanism or means  260  to connect a pneumatic source to these flow passages is located on the outside of the valve. Pneumatic pressure applied between the respective stationary plates and the pistons, urges the pistons to move in opposite directions. Steps  262  in the valve body prevent the stationary plate from moving, steps  264  on the flow tube  232  cause the piston movement to be transferred to tube and valve mechanism  234  opening the valve  200 . This embodiment also illustrates that the seal member  234  can be disposed adjacent the outlet  204  as an alternative to the previous embodiments which show sealing with the valve seat adjacent the inlet. 
       FIGS. 2H-J  shows the same valve described in  FIGS. 2B-D  except with an alternative valve mechanism. In this design the shut off seal  266  is again located downstream of diaphragms  212 ,  214  which may be more desirable in some situations, and is also secured in a C-shaped clip that engages the valve body at a central location positioned radially inward of angled flow passages extending inwardly from the outlet  204 . However, one skilled in the art will recognize that the seal member could alternately be located on the body for selective engagement with the tube end that would define the valve seat if so desired. 
       FIG. 3A  shows a typical high purity adjustable valve. In this design there is a threaded valve stem that can be rotated to adjust the movement of the diaphragm and therefore the valve opening. 
       FIGS. 3B-D  shows a high purity in-line flow path valve  300  similar to the toggle valve of  FIGS. 1B-1D  above except that the toggle stem and handle are replaced by a threaded valve stem  366 . Again, for purposes of brevity and consistency, where possible like elements will be identified by like reference numerals in the  300  series. Unlike the toggle lever that moves the stem to full open in one quick motion the threaded valve stem  366  allows this movement made in precise increments adjusting the flow rate. 
       FIGS. 3E-G  shows another version of an in-line flow path high purity adjustable valve  300 . In the space between the diaphragms  312 ,  314  there is an adjustment knob  368  mounted outside the valve body  306  perpendicular to the flow path. This adjustment knob  368  drives a shaft  370  which rotates inside of the valve body. Attached to this shaft  370  is a bevel gear  372  which rotates a second mating bevel gear  374  positioned perpendicular to the first gear and whose rotational axis is parallel to the flow path. This second gear  374  has a threaded hole through the center and a matching threaded tube  376  inside. This threaded tube and gear surround the flow tube  332  located between the diaphragms  312 ,  314 . As the adjustment knob  368  is rotated the threaded tube  376  moves in a parallel direction to the flow path. This lateral movement pushes on stops on the flow tube inside it causing it to adjust the valve opening. 
       FIGS. 3H-J  shows a three wedged washer design similar to the toggle valve shown in  FIGS. 1E-G . Therefore, like reference numerals in the  300  series are similar in structure and function to that shown and described in  FIGS. 1E-G . 
     Pressure Regulator 
       FIG. 4A  shows a typical pressure regulator which has a body with right angle flow paths and a single diaphragm. This design has been used for decades and how the illustrated pressure regulator of  FIG. 4A  functions is well known. There is a mechanism to vary a spring force against one side of the diaphragm and the fluid pressure applies force to the other side. A valve responds to the movement of the diaphragm regulating the flow and pressure. 
       FIGS. 4B-D  show an in-line flow path regulator design  400 . This pressure regulator design  400  is similar to the pneumatic valve  200  describe in  FIGS. 2B-D  where one diaphragm  414  has a larger surface area than the other diaphragm  412 . Again, a valve mechanism  434  is located at one end of the tube  432  except this time the valve mechanism is configured to meter the flow as well as shut off flow completely. In the space between the diaphragms that is exterior to the flow stream, there is a mechanical mechanism or means (similar to those used in  FIG. 3B-D  or  3 E-G) except this time the mechanical mechanism is used to adjust a spring force from spring  478  to urge the valve in the open position. As pressure inside the valve housing increases, the pressure will apply more force on the larger surface area diaphragm  414  and therefore will urge the tube  432  towards the valve seat  436 . Hence, as the force from the fluid pressure approaches the force of spring  478 , the valve will restrict and eventually shut off inlet  402  flow. Increasing the force of the spring  478  will require more force to close the valve resulting in a higher system pressure. 
       FIGS. 4E-G  shows another in-line flow path regulator design  400  that uses an external pressure source  460  between the diaphragms. This pressure will apply more force to the diaphragm  414  with the larger surface area which will urge the valve  434  to the open position until the valve is balanced by the process gas pressure. This is similar to what the industry refers to as a dome loaded regulator. 
     Purge Valve Assembly 
     Most semiconductor industry gas systems require a purge valve assembly which can shut off the process gas and introduce an inert gas such as nitrogen to purge the system during down times.  FIG. 5A  show a typical high purity purge valve assembly. This is actually two valves, one to turn off and on the process gas and one to turn off and on the purge gas. They are mounted into one body because it is desirable to have the purge gas enter the system as close as possible to the valve seat of the process gas. 
       FIGS. 5B-D  shows this valve arrangement redesigned to an in-line flow path configuration. The process gas is controlled by a pneumatic process valve  500  like the one described in  FIGS. 2B-D . This process valve  500  is mated to an adaptor  580  which has a side port  580  for introducing the purge gas to the system. A purge valve  500 ′ similar to the pneumatic valve of  FIGS. 2B-2D  is mated to this adaptor  580  however this purge valve  500 ′ is installed in the opposite direction as the process valve  500 . This arrangement with the two valve seals  534 ,  534 ′ facing each other with only a thin web of steel  582  separating them is extremely desirable in a purge valve. There are also significant safety features inherent in this design. It is important in the purging procedure that there is enough purge gas pressure to prevent flow from going in the reverse direction when the valve is opened. By adjusting the pressures of the purge gas and the pneumatic gas, a situation can be set up where the pneumatic pressure cannot open the purge valve without the additional force from the purge gas pressure. 
       FIGS. 5E-G  illustrate another means to prevent reverse flow in the purge line by using the addition of a check valve  584 .  FIGS. 5E-G  show how a donut shaped plunger  586  having first and second O-ring seals  588 ,  590  provided radially inwardly and radially outwardly, respectively, of where the side port passage terminates in the assembly and the plunger  586  can be installed within the purge valve  500 ′ to prevent reverse flow. 
       FIGS. 5H-J  show a purge valve  500 ′ with yet another safety feature. This valve prevents the purge valve from being opened if the process gas valve has not been closed. This is accomplished by adding a third diaphragm  588  which is larger than the other two diaphragms  512 ,  514 . To open this valve, pneumatic pressure is applied between the first two diaphragms (viewed left to fight in these figures), one being larger than the other causing it to function then same as the valve described in  FIGS. 5B-D . The port  590  between the second and third diaphragms is a vent port that could possibly be monitored by a PC mounted transducer. The third diaphragm  588  is larger than the other two and is exposed to the process gas pressure on the downstream side, hence the third diaphragm prevents the purge gas from being opened unless the process gas pressure is reduced significantly below the pneumatic pressure. 
       FIGS. 5K-N  show a method of making attachments to the pneumatic and purge ports using a saddle shaped block  590  which is attached to the system using the same bolts  591  that clamp the flow components together. The pneumatic gas can be attached to the saddle block  590  using any standard threaded fitting. The purge (high purity) gas can be connected using a standard microfit elbow  592 , one end  593  of one arm of the elbow is pressed against a soft seat  594  in a counter bore in the body, force is applied to the back of the elbow with a set screw  595  in the saddle. 
       FIGS. 5O-5Q  show another method of connecting to the purge port. In this design a tube  596  with a flange  597  is welded to one arm  598  of a microfit elbow and a split nut  599  is used to press the end of the tube against a seat. 
     Filter 
     Many filters already have inline flow paths.  FIG. 6  shows how they can be installed in an in-line flow systems by replacing the inlet and outlet body housings with a simple adaptor ring AR. 
     In Line Flow Systems 
       FIGS. 7 and 8  show how these in-line flow path components can be combined to make very compact high purity gas systems.  FIGS. 7A-7C  show the combination of a toggle valve, a pressure regulator and a pneumatic valve. Inlet and outlet housings have been added to make connection to the system.  FIG. 7D  shows the inlet and outlet housing made with an integral square configuration which allows room for bolt holes in the corners. Bolts can then be used to clamp the components together instead of welding.  FIG. 7E  shows the same system but with flanges and bolts holding the components together. 
       FIGS. 8A and 8B and 8C  show a system that combines seven components, a toggle valve, a pneumatic valve, a pressure regulator, an adjustment valve, a filter, a purge valve, and another pneumatic valve.  FIG. 8A  shows these components with their inlet and outlet housings removed,  8   b  shows them welded together.  FIG. 8D  shows this seven component system in the bolted configuration with the pneumatic and purge connections.  FIG. 8E  has a printed circuit board PCB installed with mini pneumatic valves and pressure transducers. The adjustment and toggle handles can obviously be rotated to allow the saddle and PC board to span all the pneumatic and vent ports. 
     Check Valve 
       FIGS. 9A and 9B  show how the check valve feature incorporated in  FIG. 5E-G  can be installed in a separate housing creating a three way check valve component. This component could be useful when mixing fluids down steam of the above systems. 
     The disclosure has been described with reference to the preferred embodiments. Modifications and alterations will occur to others upon reading and understanding this specification. It is intended to include all such modifications and alterations in so far as they come within the scope of the appended claims or the equivalents thereof.