Gas purge valve

Abstract

A valve (100) comprising: a housing (102) having at least one inlet (104a) and at least one outlet (104b); a valve member (108) located within said housing (102) and movable between different positions for controlling in use the flow of fluid from the inlet (104a) to the outlet (104b) of the valve (100); wherein the valve (100) further comprises: at least two spaced valve seats (110a, 110b) in which the valve member (108) is located so as to form a chamber (112) defined by the valve seats (110a, 110b), the outer surface of the valve member (108) and the inner surface of the housing (102); a first conduit (118) extending between the outside of the housing (102) and the chamber (112); and a second conduit (125) extending between the chamber (112) and a bore (114) of the valve member (108), through which in use purge gas can be introduced into the chamber (112) and the bore (114). Preferably, the purge gas is pressurized and optionally heated using a cartridge heater (126) to respectively inhibit the escape and condensation of process gas.

Description

Technical Field

[0001] The present invention relates to valves and, in particular, but not by way of limitation, to a gas purge valve that significantly reduces or eliminates the release of corrosive, toxic, self-igniting, and / or harmful gases into the surrounding environment in the event of a valve failure. The present invention also relates to a system having a vacuum pump, a gas abatement system, and a gas purge valve according to the present invention. Background Art

[0002] The manufacture of semiconductor devices, flat panel displays, and solar panels involves various process steps (such as etching, deposition, and cleaning) that are typically carried out under vacuum conditions. To achieve such conditions, one or more vacuum pumps are connected to the outlet of each process chamber. During operation, the vacuum pumps receive unused process gases and / or by-products that leave the process chamber. The unused gases and by-products are typically corrosive, toxic, self-igniting, and / or hazardous gases that cannot be released directly into the environment. Accordingly, each vacuum pump exhausts into one or more gas abatement systems. Manufacturers typically install two abatement systems in parallel, with one system operating in an "online" mode and the other system operating in an "offline" mode. The dual systems together provide enhanced uptime in the event of a failure or need for preventive maintenance of the abatement system. During such a failure or maintenance, an isolation valve isolates the offline system from the online system. Each inlet line of each abatement system includes an isolation valve that alternates between the online abatement system and the offline abatement system. Since the unused process gases and by-products flow through the isolation valve, the O-ring seals or valve seats of the valve may fail. Such a failure may cause pressurized gas to continue to flow into the offline abatement system even after the isolation valve is "closed". Thus, when technicians service the offline system, corrosive, self-igniting, toxic, and / or hazardous gases may be released into the environment, harmfully injuring the surrounding people and property.

[0003] To minimize the release of gases, manufacturers typically include a second manually operated isolation valve in the inlet lines of both the online and offline abatement systems. Before servicing the offline abatement system, technicians must also close the manual valve to ensure that pressurized gas no longer flows into the system. However, technicians sometimes forget to close or reopen the manual valve. Thus, adding the manual valve may have several drawbacks. First, adding the second valve increases the cost of the system. Second, even with the second manual valve, there is a small risk of accidental exposure if the ball or seal of the manual valve becomes damaged. Third, if a technician forgets to reopen the manual valve, for example, then a catastrophic failure will occur in the processing system when the main system goes offline and switches to the auxiliary system.

[0004] Accordingly, there is a need for a single, reliable isolation valve that can isolate an offline abatement system from an online abatement system and substantially reduce or eliminate the release of corrosive, toxic, self - igniting, and / or hazardous gases. Similarly, there is a need for a processing system that provides cost - effective redundancy and enhanced safety. Summary of the Invention

[0005] According to a first aspect of the present invention, there is provided a valve comprising: a housing having at least one inlet and at least one outlet; a valve member located within the housing and movable between different positions for controlling the flow of fluid from the inlet to the outlet of the valve in use; wherein the valve further comprises: at least two spaced - apart valve seats in which the valve member is located so as to form a cavity defined by the valve seats, the outer surface of the valve member, and the inner surface of the housing; a first conduit extending between the outside of the housing and the cavity; and a second conduit extending between the cavity and a bore of the valve member, through which purge gas can be introduced into the cavity and the bore in use.

[0006] Preferably, a pressurized gas or purge gas can optionally but preferably be introduced into the cavity to ensure that process gas cannot escape from the housing. In some cases, this may involve providing a continuous flow of purge gas into the cavity or the bore to maintain a positive pressure within the cavity or to inhibit back - flow or the escape of process gas through either orifice from the housing.

[0007] One envisaged advantage of the present invention is that, in the event of a malfunction or failure, it can provide protection for the people and environment around the valve. This can be achieved by providing a method to purge potentially harmful gases from the valve and replace them with (preferably) an inert or harmless purge gas such that if the valve leaks, malfunctions, or operates incorrectly, the inert or harmless purge gas is more likely to escape than the potentially harmful process gas. In practice, this is achieved by surrounding the movable valve member with a continuously supplied purge gas and by allowing the purge gas to enter the bore of the valve member.

[0008] Advantageously, the second conduit extending between the cavity and the bore of the valve member allows purge gas to enter the cavity and the bore of the valve member in a first (“open”) position, i.e., when the bore is aligned with the inlet and outlet of the valve. Thus, when the valve is in the first position, the risk of process gas escaping from the housing can be reduced. This is because purge gas can be allowed to flow from the flow path and into the cavity, and the purge gas can flow from the cavity through the second conduit into the bore of the valve member, where the purge gas combines with the process gas before leaving the valve. The purge gas can be supplied at a pressure greater than the normal maximum pressure of the process gas such that the purge gas can flow into the process gas stream.

[0009] The valve can be an isolation valve or a diverter valve, such as can be used in a vacuum system with a redundant gas abatement system. In the case of an isolation valve, the valve member can include a hole such that when moved or rotated to a first position, the hole is aligned with the inlet and outlet of the valve, and / or such that when moved or rotated to a second position, the hole is not aligned with the inlet or outlet. Of course, when the valve member is moved to the second (“closed”) position, the purge gas may be stagnant (dead-headed, no flow).

[0010] In the case of a diverter valve, the valve member can be movable or rotatable between a first position and a second position such that the hole is aligned with the inlet and a first outlet in the first position and with the inlet and a second outlet in the second position.

[0011] To inhibit or prevent the backflow of purge gas out of the housing, a check valve is preferably provided. The check valve can include a spring, the tension of which can be adjustable, and the spring is preferably made of an alloy having a high nickel content, such as a mnemonic (or “shape memory”) alloy, such as Nitinal TM .

[0012] To facilitate the introduction of purge gas into the valve, a manifold can be provided to enable the purge gas to be introduced from outside the housing into the purge gas conduit.

[0013] A heater, such as a suitably designated cartridge heater, can be provided to heat the manifold and thus heat the purge gas within the manifold before the purge gas enters the chamber. Such an arrangement can inhibit or prevent condensation within any part of the manifold or the valve.

[0014] In the case where it is provided, the manifold can be used as a heat exchanger for transferring heat from the heater or cartridge heater to the purge gas therein. To maximize the heat exchange efficiency, the manifold is preferably made of a material with high thermal conductivity, such as copper or aluminum alloy. By designing the flow path of the purge gas within the manifold to have a large surface area and follow a non-linear path, the heat transfer from the heater or cartridge heater can be maximized. Thus, the flow path of the purge gas through the manifold is preferably interrupted, which can be achieved by increasing the turbulence of the purge gas flowing through the manifold, a tortuous flow path for the purge gas flowing through the manifold, the proper use of baffles and packing materials in the flow path.

[0015] In most practical cases, a purge gas supply connected to the inlet of the manifold is preferably present.

[0016] As previously implied, the integrity of the valve can be checked by monitoring the pressure or flow rate of the purge gas in any one or more of the groups including: the chamber; the first and second ducts; the manifold; and the purge gas supply. In some cases, this can be achieved by using a pressure sensor or a flow sensor. In the most preferred embodiment of the present invention, the pressure sensor is positioned within the purge gas supply, and the valve and the pressure regulator are provided upstream of the pressure sensor together with a valve for isolating the purge gas within the chamber and the manifold, the pressure sensor being adapted to monitor the pressure of the isolated purge gas.

[0017] For compatibility with the foregoing manufacturing process, the wetted components are preferably selected to be compatible with the process gas flowing through the valve, such as being compatible with fluorine, chlorine, and hydrogen bromide. In a similar manner, the valve seat is also preferably manufactured from a material that is resistant to chemical and physical erosion by the process gas, such materials being, for example, stainless steel, Hasteloy TM , Viton TM and Kalrez TM .

[0018] A second aspect of the present invention provides a system comprising: a vacuum pump having an exhaust device; and a pair of abatement systems teed to the exhaust device, and a valve as described herein, the valve being positioned upstream of each of the abatement systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Preferred embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:

[0020] Figure 1 is a schematic view of a gas purge ball valve according to the present invention;

[0021] Figure 2a is a side view of a gas purge ball valve according to the present invention (shown in the open position);

[0022] Figure 2b is an end view of a gas purge ball valve according to the present invention (shown in the closed position);

[0023] Figure 2c is a side view of a gas purge ball valve according to the present invention (shown in the closed position);

[0024] Figure 3a is a schematic view of a gas purge ball valve according to the present invention having purge gas pressure detection;

[0025] Figure 3b is a schematic view of a gas purge ball valve according to the present invention having flow rate purge gas detection;

[0026] Figure 4aCross-sectional view of a diverter valve according to the present invention;

[0027] Figure 4b View of a manifold connected to a diverter valve according to the present invention;

[0028] Figure 5 Plan view of a diverter valve according to the present invention;

[0029] Figure 6a Schematic diagram of a system having a pair of gas purge ball valves according to the present invention; and

[0030] Figure 6b Schematic diagram of a system having a gas purge diverter valve according to the present invention. DETAILED DESCRIPTION

[0031] The isolation valve of the present invention can be a ball valve or a diverter valve. Figure 1 An embodiment of a gas purge ball valve according to the present invention is shown. The ball valve 100 has a housing 102 with an inlet 104a and an outlet 104b. The valve 100 also includes a rotatable ball 108 located between a pair of valve seats 110a, 110b. The valve seats 110a, 110b are respectively positioned in the inlet 104a and the outlet 104b of the valve 100.

[0032] The ball 108 has a bore 114 therethrough, and the ball 108 can rotate between a first position and a second position. The bore 114 is aligned with the inlet 104a and the outlet 104b in the first position (see Figure 2a ), and is misaligned or perpendicular to the inlet 104a and the outlet 104b in the second position (see Figure 2b - 2c ). The alignment of the bore 114 with the inlet 104a and the outlet 104b forms an "open" process flow path through the valve 100. The ball 108 is spaced from the inner surface of the housing 102 to form a cavity 112 therebetween, as shown in Figure 1 and more specifically in Figure 2a - 2c . As will be discussed in further detail below, the cavity 112 or "void" between the valve seats 110a, 110b and the housing 102 is purged with an inert gas. As shown in Figure 2b , the ball 108 also includes a keyway 123 that engages a drive dog 119 of the valve 100. A small opening 125 in the ball 108 near the keyway 123 enables the bore 114 to be in fluid communication with the cavity 112.

[0033] A manifold 116 having a flow path 118 with an inlet 120a and an outlet 120b is tightly coupled to the housing 102. A source 124 of pressurized inert gas, such as nitrogen, argon, or helium, is connected to the manifold inlet 120a. The outlet 120b of the manifold 116 is in fluid communication with a port 122 in the housing 102, as shown inFigure 2b As shown in. Port 122 passes through housing 102 and enters chamber 112, thereby connecting flow path 118 to chamber 112. Thus, manifold 116 enables chamber 112 to be filled with an inert purge gas. Although manifold 116 can be constructed from a variety of solid materials, it is preferably constructed from a material having a high thermal conductivity, such as aluminum alloy or copper.

[0034] Check valve 128 is positioned in port 122 such that inert gas can flow from manifold 116 into chamber 112, but not in the opposite direction. In one embodiment, a spring (not shown) is positioned in port 122 between the ball (not shown) of check valve 128 and ball 108 of isolation valve 100. The spring establishes a minimum pressure at which purge gas must enter port 122 and chamber 112.

[0035] Certain process steps require heat to prevent the formation of solid by-products in the plumbing and components (such as valves, vacuum pumps, etc.) downstream of the process tool. For example, the condensable solid, aluminum chloride (Al 2 Cl 6 ) is a by-product of the aluminum etching process. In another example, ammonium hexafluorosilicate ((NH 4 )) 2 SiF 6 ) is a condensable by-product of the silicon nitride chemical vapor deposition process using fluorine-based chamber cleaning. Therefore, it is preferred to heat the purge gas supplied to chamber 112 in order to minimize condensation within ball 108 of valve 100 and housing 102.

[0036] As Figure 2b and Figure 2c shown, manifold 116 includes heater 126, such as a cartridge heater, sized to maintain the temperature of the purge gas in order to minimize condensation within ball 108 of valve 100 and housing 102. Heater 126 should maintain the temperature of the purge gas at about 90 °C or above, and preferably at about 120 °C or above. If manifold 116 is constructed from a material having a high thermal conductivity, such as aluminum alloy or copper, heater 126 can be positioned at any convenient location within manifold 116. However, preferably, heater 126 is positioned closer to manifold outlet 120b than to manifold inlet 120a. As Figure 2b and Figure 2c shown, heater 126 is positioned within manifold 116, adjacent to flow path 118 and manifold outlet 120b.

[0037] In addition, the flow path 118 is preferably optimized for heat transfer from the heater 126 to the purge gas flowing through the manifold 116. Thus, in one embodiment, the flow path 118 is tortuous such that the purge gas must flow back and forth through the manifold 116 before exiting into the inlet port 122. In another embodiment, the flow path 118 may include baffles to increase turbulence or may be a packed bed to enhance heat transfer.

[0038] As discussed above, the isolation ball valve 100 has a first position and a second position. Figure 2a The valve 100 is shown in a first "open" position, and Figure 2b and 2c the valve 100 is shown in a second "closed" position. When the valve 100 is "open", process gas flows into the valve 100 through the valve inlet 104a, through the bore 114 of the ball 108, and out through the valve outlet 104b. See Figure 2a . When process gas flows through the "open" valve 100, heated purge gas flows from the flow path 118 of the manifold 116 into the cavity 112, thereby heating the ball 108 and the housing 102. The heated purge gas flows from the cavity 112 through the opening 125 into the bore 114 of the ball 108 where the heated purge gas combines with the process gas before exiting the valve 100. Preferably, the pressure of the heated inert gas supplied to the cavity 112 is higher than the normal maximum pressure of the process gas stream such that the inert gas can flow into the process gas.

[0039] When the ball valve 100 is "closed", as Figure 2b and 2c shown, and there is no leakage in the valve 100, the heated purge gas continues to flow into the cavity 112 and the bore 114 until the pressure of the purge gas within the valve 100 reaches the pressure of the inert gas source 124. Thus, under normal conditions, the purge gas is stagnant through the "closed" valve 100. However, if the isolation valve 100 is damaged, for example due to a scratch on the ball or a corroded valve seat and / or O-ring, the harmless inert gas rather than the harmful process gas will leak from the cavity 112 and through the damaged area.

[0040] To detect a leak or damage in the isolation valve 100, the pressure decay of the heated inert purge gas can be monitored. In one embodiment, a solenoid valve 130 is installed in the inert gas source line 135 upstream of the manifold inlet 120a together with a pressure regulator 132 to regulate the pressure to the manifold 116, as Figure 3a shown. A pressure sensor 134 is also positioned in the inert gas source line between the manifold inlet 120a and the solenoid valve 130 to monitor the pressure in the manifold 116. A heater 126 is positioned within the manifold 116 upstream of the check valve 138. Under normal operating conditions, the pressure of the inert gas should remain at a constant predetermined value.

[0041] As discussed above, the pressure of the heated inert gas in chamber 112 should be higher than the maximum operating pressure of the process gas stream. The maximum pressure of the process gas stream is in turn determined by the equipment characteristics such as the abatement system located downstream of the process chamber. For example, if the abatement system is a burner (e.g., see U.S. Patent No. 7,494,633 to Stanton et al. and assigned to Edwards Limited) or a wet scrubber, the pressure of the process gas stream can be about ±5 inH 2 O (or about ±0.181 psi or 0.012 Bar). However, if the abatement system is a gas reactor tower (e.g., see U.S. Patent No. 5,538,702 to Smith et al. and U.S. Publication No. 2005 / 0217732A1 to Martin Ernst Tollner), the pressure of the process gas stream can be as high as about 3.5 psi (i.e., about 0.24 Bar). Thus, in the former example, the pressure of the purge gas supplied to valve 100 should be from about 1 psi to about 5 psi (i.e., about 0.07 Bar to 0.34 Bar). In the latter example, the pressure of the purge gas supplied to valve 100 should be from about 5 to about 15 psi (i.e., about 0.34 to 1.03 Bar).

[0042] During operation, shortly after the isolation (ball) valve 100 is rotated to the second "closed" position and the pressure of the heated inert gas in valve 100 has had a chance to stagnate, the solenoid valve 130 is also "closed". Thus, chamber 112 becomes filled with inert gas at a certain pressure as discussed in the previous paragraph. Thus, if there is no leakage in the valve, the pressure of the inert gas measured by pressure sensor 134 will remain constant. However, if pressure sensor 134 measures a decay (or decrease) in the pressure of the inert gas, this decay indicates a leak in isolation valve 100.

[0043] In another embodiment, a flow sensor 136 is positioned in the purge gas line 135 to monitor the flow rate of the purge gas, as Figure 3bAs shown. The pressure regulator 132 is also positioned in the purge gas line 135, upstream of the flow sensor 136. The heater 126 is positioned within the manifold 116 upstream of the check valve 138. Under normal circumstances, as discussed above regarding measuring pressure decay, the purge gas is stagnant within the chamber 112. However, if the flow sensor 136 detects a flow of purge gas, then this flow indicates a leak in the isolation valve 100. Notably, both the flow rate and the pressure decay of the purge gas line 135 can be monitored to detect a malfunction of the isolation valve 100. To achieve this, the flow sensor 136 can be installed between the pressure sensor 134 and the manifold inlet 120a.

[0044] In another embodiment, the isolation valve is a diverter valve 200 as shown in Figure 4a . In this embodiment, the diverter valve 200 has a housing 202, which has an inlet 204a (shown in Figure 5 ) and two outlets 204b and 204c. The diverter valve 200 also has a rotatable ball 208 located between valve seats 210a, 210b, 210c, 210d. The valve seats 210a, 210b, 210c, 210d are positioned around the ball 208, as shown in Figure 4.

[0045] The ball 208 has a hole with two limbs 214a, 214b, which are arranged to form a single "L" - shaped configuration as shown in Figure 5 . Notably, the holes 214a, 214b are positioned in the plane represented by the horizontal dashed line in Figure 4a . However, the axis of rotation of the ball 208 represented by the vertical dashed line in Figure 4a is perpendicular to this plane. This perpendicular configuration is necessary to isolate the chamber 212 (described below) from the process fluid flow path through the holes 214a, 214b of the valve 200.

[0046] The ball 208 is rotatable between a first position and a second position. In the first position, the hole 214a is aligned with the inlet 204a, and the hole 214b is aligned with the outlet 204b. In this first position, the process gas flows from the inlet 204a and through the outlet 204b. In the second position, as shown in Figure 4a , the ball 208 rotates such that the hole 214b is aligned with the inlet 204a, and the hole 214a is aligned with the outlet 204c. In this second position, the process gas flows from the inlet 204a and through the outlet 204c.

[0047] The ball 208 is spaced from the inner surface of the housing to form a chamber 212 therein, as shown in Figure 4a . The chamber 212 is purged with an inert gas, as will be described in detail below. As shown in Figure 4aAs shown in, the ball 208 includes a keyway 223 that engages with the drive block 219 of the valve 200. A small opening 225 in the ball 208 near the keyway 223 enables the chamber 212 to be in fluid communication with the holes 214a, 214b. The size of the small opening 225 must be designed to provide the necessary pressure drop to allow the chamber 212 to operate at a higher pressure than the process fluid flow.

[0048] As Figure 4a and 4b shown in, a manifold 216 having a flow path 218 with an inlet 220a and an outlet 220b is closely coupled to the housing 202. A pressurized source 224 of an inert gas, such as nitrogen, argon, or helium, is connected to the manifold inlet 220a. The outlet 220b of the manifold 216 is in fluid communication with a port 222 in the housing 202, as shown in FIG. 4. The port 222 passes through the valve housing 202 and into the chamber 212, thereby connecting the flow path 218 to the chamber 212. Thus, the manifold 216 enables the chamber 212 to be filled with a pressurized inert purge gas. Although the manifold 216 can be constructed of a variety of solid materials, it is preferably constructed of a material having a high thermal conductivity, such as aluminum alloy or copper.

[0049] A one-way (check) valve 228 is positioned in the port 222 such that the inert gas can flow from the manifold 216 into the chamber 212, but not in the opposite direction. In one embodiment, a spring (not shown) is positioned in the port 222 between the ball 229 of the check valve 228 and the ball 208 of the isolation valve 200. The spring establishes a minimum pressure at which the purge gas must enter the port 222 and the chamber 212.

[0050] As Figure 4b shown in, the manifold 216 preferably includes a heater 226, such as a cartridge heater, sized to maintain the temperature of the purge gas to minimize condensation within the ball 208 of the valve 200 and the housing 202. The heater 226 should maintain the temperature of the purge gas at or about 90 °C and preferably above about 120 °C. If the manifold 216 is constructed of a material having a high thermal conductivity, such as aluminum alloy or copper, the heater 226 can be positioned at any convenient location within the manifold 216. However, preferably, the heater 226 is positioned closer to the manifold outlet 220b than to the manifold inlet 220a. As Figure 4b shown in, the heater 226 is positioned within the manifold 216, near the flow path 218 and the manifold outlet 220b.

[0051] In addition, the flow path 218 preferably optimizes heat transfer from the heater 226 to the purge gas flowing through the manifold 216. Thus, in one embodiment, the flow path 218 is tortuous, as Figure 4aAs shown, the purge gas must flow back and forth through the manifold 216 before entering port 222. In another embodiment, the flow path 218 may include baffles to increase turbulence or may be a packed bed to enhance heat transfer.

[0052] As discussed above, the isolation diverter valve 200 has a first position and a second position. When the holes 214a and 214b are aligned with the inlet 204a and the outlet 204b respectively, the process gas flows into the valve 200 through the inlet 204a, through the holes 214a, 214b of the ball 208, and flows out through the outlet 204b. When the process gas flows through the holes 214a, 214b, the heated purge gas flows from the flow path 218 of the manifold 216 into the chamber 212, thereby heating the ball 208 and the housing 202. The heated purge gas flows from the chamber 212 through the opening 225 into the holes 214a, 214b of the ball 208, where the heated purge gas combines with the process fluid before leaving the valve 200. Preferably, the pressure of the heated inert gas supplied to the chamber 212 is higher than the normal maximum pressure of the process gas flow, so that the inert gas can flow into the process gas flow.

[0053] Similarly, when the holes 214a and 214b are aligned with the outlet 204c and the inlet 204a respectively, the process gas flows into the inlet 204a and out through the outlet 204c. See Figure 4a As in the first position, the heated inert purge gas flows into the holes 214a, 214b and combines with the process fluid. In addition, the pressure of the inert purge gas is preferably higher than the operating pressure of the process gas.

[0054] Therefore, during operation, when the valve 200 is in the first or second position, the heated inert purge gas constantly flows into the chamber and the holes 214a, 214b. As discussed above, the size of the port 222 is designed to ensure that the pressure of the purge gas exceeds the pressure of the process gas and to control the flow of the purge gas into the holes 214a, 214b. If the valve 200 fails, for example due to corrosion of the valve seat, the flow rate of the inert purge gas will increase. Therefore, using the same construction as shown in Figure 3b A flow sensor can be positioned in the purge gas line to monitor the flow rate of the purge gas. If the flow sensor detects a relative increase in the flow rate, this will be an indication of valve failure.

[0055] The wetted components of the isolation valves 100, 200, such as the housings, balls 108, 208, and valve seats 110a, 110b, must be compatible with gases such as fluorine, chlorine, hydrogen bromide, and other gases used in semiconductor, flat panel display, and solar panel manufacturing processes. Similarly, the wetted components of the check valves 128, 228, such as balls 229, springs (not shown), washers (not shown), and seal rings (not shown), must also be compatible with the above gases. The balls 108, 208, and ball 229 are preferably constructed of stainless steel (such as 304L, 316L, etc.) that is corrosion resistant to the above gases. The spring (not shown) should be constructed of an alloy or memory material having a high nickel content (such as those made of Inco alloys). The washers and seal rings (not shown) should be constructed of stainless steel (such as 304L, 316L, etc.), Hastelloy, Viton ® or Kalrez ® The manifold 116 can be constructed of a relatively inexpensive material such as aluminum.

[0056] A system 300 having the isolation valves 100, 200 according to the present invention is also provided. Figure 6a A system 300 according to the present invention is shown. The system 300 has redundancy reduction systems 302a, 302b to receive the exhaust 304 from one or more vacuum pumps 306 connected to an outlet 307 of a process chamber 308. The exhaust pipeline 304 is connected to each of the reduction systems 302a, 302b in a T-connection, and in Figure 6a the embodiment shown, the isolation valves 100 are installed in each of the pipelines of the T-connection. In Figure 6b another embodiment 301 shown, a diverter valve 200 according to the present invention is installed at the T-connection upstream of the reduction systems 302a, 302b. In both embodiments 300, 301, the isolation valves 100, 200 are constructed and operate as described above.

[0057] As described above and shown in Figures 1 - 6b the embodiments of the present invention provide cost-effective redundancy and enhanced safety in semiconductor, solar panel, and flat panel display processes. It is contemplated that other embodiments and variations of the present invention will become apparent to those skilled in the art from the foregoing description, and it is intended that these embodiments and variations are also included within the scope of the present invention as set forth in the appended claims.

[0058] Reference Signs

[0059] 100. Ball valve

[0060] 102 Housing

[0061] 104a. Inlet

[0062] 104b. Outlet

[0063] 108. Ball

[0064] 110a. Valve seat

[0065] 110b. Valve seat

[0066] 112. Chamber

[0067] 114. Hole

[0068] 116. Manifold

[0069] 118. Flow path

[0070] 119. Drive block

[0071] 120a. Manifold inlet

[0072] 120b. Manifold outlet

[0073] 122. Port

[0074] 123. Keyway

[0075] 124. Inert gas source

[0076] 125. Opening

[0077] 126. Heater

[0078] 128. Check valve

[0079] 130. Solenoid valve

[0080] 132. Pressure regulator

[0081] 134. Pressure sensor

[0082] 135. Inert gas source pipeline

[0083] 136. Flow sensor

[0084] 138. Non-return valve

[0085] 200. Diverting valve

[0086] 202. Housing

[0087] 204a. Inlet

[0088] 204b. Outlet

[0089] 204c. Outlet

[0090] 208 Ball

[0091] 210a-d. Valve seat

[0092] 212. Chamber

[0093] 214a. Orifice member

[0094] 214b. Orifice member

[0095] 216. Manifold

[0096] 218. Flow path

[0097] 219. Drive stop

[0098] 220a. Inlet

[0099] 220b. Outlet

[0100] 222. Port

[0101] 223. Keyway

[0102] 224. Inert gas source

[0103] 225. Opening

[0104] 226. Heater

[0105] 228. Check valve

[0106] 229. Ball

[0107] 300. System

[0108] 302a. Abatement system

[0109] 302b. Abatement system

[0110] 304. Exhaust device

[0111] 306. Vacuum pump

[0112] 307. Outlet

[0113] 308. Process chamber.

Claims

1. A valve, comprising: a housing having at least one inlet and at least one outlet; a valve member located within the housing and movable between different positions for controlling in use the flow of fluid from the inlet to the outlet of the valve; at least two spaced-apart valve seats in which the valve member is located so as to form a chamber defined by the valve seats, the outer surface of the valve member and the inner surface of the housing; a first conduit extending between the exterior of the housing and the chamber; and a second conduit extending between the chamber and a bore of the valve member, through which purge gas can be introduced into the chamber and the bore in use, wherein the valve member is rotatable between a first position and a second position such that the bore is aligned with the inlet and the outlet in the first position and the bore is not aligned with the inlet or the outlet in the second position, and wherein when the valve member is in the second position, the purge gas is trapped in the chamber and the bore.

2. The valve according to claim 1, wherein pressurized purge gas can be introduced into the chamber and the bore.

3. The valve according to claim 1 or 2, further comprising a check valve for inhibiting or preventing the outflow of purge gas from the housing via the first conduit.

4. The valve according to claim 1 or 2, further comprising a manifold through which the purge gas is introduced from the exterior of the housing into the purge gas conduits in use.

5. The valve according to claim 4, wherein the manifold includes means for increasing the turbulence of the purge gas flowing through the manifold; and / or wherein the manifold includes a tortuous flow path for the purge gas to flow through the manifold; and / or wherein the manifold includes a flow path for the purge gas to flow through the manifold, the flow path including baffles; and / or wherein the manifold includes a flow path for the purge gas to flow through the manifold, the flow path including packing material; and / or further includes a purge gas supply connected to the inlet of the manifold.

6. The valve according to claim 1 or 2, further comprising means for monitoring the pressure or flow rate of the purge gas in the chamber and / or in the first conduit and / or in the second conduit.

7. The valve according to claim 4, further comprising means for monitoring the pressure or flow rate of the purge gas in the manifold.

8. The valve according to claim 6, further comprising means for monitoring the pressure or flow rate of the purge gas in the purge gas supply.

9. The valve according to claim 6, wherein the means for monitoring the flow rate of the purge gas includes a flow sensor.

10. The valve according to claim 9, wherein the flow sensor is positioned within the purge gas supply for monitoring the flow rate of the purge gas.

11. The valve according to claim 1 or 2, wherein the wetted components are compatible with gases selected from the group consisting of fluorine; chlorine; and hydrogen bromide.

12. The valve according to claim 3, wherein the check valve includes a spring made of an alloy having a high nickel content.

13. The valve according to claim 4, further comprising a heater for heating the purge gas within the manifold before the purge gas enters the chamber.

14. The valve according to claim 13, wherein the heater includes a cartridge heater, and / or wherein the size of the heater is designed to minimize condensation within the chamber.

15. The valve according to claim 7, wherein the means for monitoring the pressure of the purge gas includes a pressure sensor.

16. The valve according to claim 15, wherein, the pressure sensor is positioned within the purge gas supply, and wherein the valve and the pressure regulator, together with a valve for isolating the purge gas within the chamber and the manifold, are provided upstream of the pressure sensor, the pressure sensor being adapted to monitor the pressure of the isolated purge gas.

17. A system, comprising: a vacuum pump having an exhaust device; and a pair of abatement systems T-connected into the exhaust device; wherein the valve according to any one of claims 1 to 16 is positioned upstream of each of the abatement systems.

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