Granular solids of high purity are often used, for example, in the manufacture of silicon products including semiconductor wafers. Valves are used to control the flow of the granular solids. Conventional valves, such as ball or gate valves, are ill-suited for controlling the flow of the granules in the manufacturing process. The use of conventional valves often results in material being abraded from the valves and contaminating the granules. Moreover, conventional valves may be unable to completely close and stop the flow of granules because granules may become trapped between valve components. Angle of repose valves have been developed to address these issues. However, previous angle of repose valves suffered shortcomings. For example, prior seals cannot withstand higher gas pressures.
A first aspect is an angle of repose valve for dispensing high purity granules. The valve comprises a housing having an inlet, an outlet, an opening having a circumferential edge, and an interior cavity. A pipe extends from the inlet into the interior cavity of the housing and the pipe has a terminal end in the interior cavity of the housing. A saddle is disposed in the interior cavity of the housing. The saddle is also disposed vertically below the terminal end of the pipe and the saddle has a catch member. A shaft is coupled to the saddle and extends through the circumferential edge of the opening in the housing and is configured for coupling to a drive. A chevron seal is disposed adjacent at least the circumferential edge defining the opening in the housing through which the shaft extends and the chevron seal has a void through which the shaft passes. A compression member is engaged with the housing and is configured to exert force on the chevron seal to expand the chevron seal against at least one of the circumferential edge of the opening in the housing and the shaft. The saddle is rotatable by the shaft between a first position and a second position, wherein in the first position high purity granules are enabled to flow unimpeded by the catch member, and wherein in the second position the catch member is disposed vertically beneath the terminal end of the pipe such that high purity granules cannot flow past the saddle.
Another aspect is an angle of repose valve for dispensing high purity granules. The valve comprises a housing having an inlet and an outlet, the housing comprising a plurality of walls having a thickness of at least about 0.95 inches. A pipe extends from the inlet into an interior cavity of the housing and the pipe has a terminal end in the interior cavity of the housing. A saddle is disposed in the interior cavity of the housing vertically below the terminal end of the pipe. The saddle is coupled to a shaft extending through an opening in the housing. A seal plate is coupled to an exterior surface of the housing and has an opening therein disposed adjacent the opening in the housing. The seal plate has a groove formed therein sized for receiving an o-ring and is configured such that the valve is able to dispense the high purity granules with a gas having a pressure of at least about 80 pounds per square inch.
Still another aspect is an angle of repose valve for dispensing high purity granules with a pressurized gas. The valve comprises a housing having an inlet, an outlet, an opening having a circumferential edge, and an interior cavity. The housing has a plurality of walls having a thickness of at least about 0.95 inches. A pipe extends into the interior cavity of the housing and has a terminal end in the internal cavity. A saddle is disposed in the interior cavity of the housing vertically below the terminal end of the pipe. A shaft is coupled to the saddle and extends through the opening in the housing. A chevron seal is disposed adjacent at least the circumferential edge of the opening in the housing through which the shaft extends. The chevron seal has a void through which the shaft passes. A compression member is threadably engaged with the housing and configured to exert force on the chevron seal when rotated in one of a clockwise direction and a counter clockwise direction. The force exerted on the chevron seal causes it to expand against at least one of the circumferential edge of the opening in the housing and the shaft.
Still another aspect is a method of repairing a leak in an angle of repose valve for dispensing high purity granules with a pressurized gas. The angle of repose valve comprises a housing and a saddle disposed therein, a shaft coupled to the saddle and extending through an opening in the housing, a chevron seal positioned between the shaft and the opening in the housing, and a compression member threadably engaged with the housing and configured to exert a compression force on the chevron seal upon tightening of the compression member. The method comprises detecting a first leak of one of the pressurized gas and high purity granules through the opening in the housing. The compression member is then tightened by a first amount when the first leak is detected. Tightening the compression member by the first amount results in a first force being exerted on the chevron seal that expands the chevron seal laterally between the shaft and the opening in the housing to repair the first leak by reducing or eliminating the first leak. Tightening the compression member by the first amount permits rotation of the shaft with respect to the opening in the housing.
Various refinements exist of the features noted in relation to the above-mentioned aspects. Further features may also be incorporated in the above-mentioned aspects as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to any of the illustrated embodiments may be incorporated into any of the above-described aspects, alone or in any combination.
With reference now to the Figures, and in particular to
In the valve system 100 of
A first pipe 140 couples the first container 110 to the angle of repose valve 130 and permits the granules 102 to flow from the first container into the angle of repose valve. The first container 110 is coupled to a source of pressurized gas in this embodiment to aid in the flow of granules 102 from the first container into the first pipe 140 and the angle of repose valve 130. In another embodiment, pressurized gas is not used and instead gravity is solely relied upon to convey the granules 102 from the first container 110 into the first pipe 140 and the angle of repose valve 130.
A second pipe 150 couples a conventional valve 160 to the angle of repose valve 130. The conventional valve 160 is any type of valve that is capable of preventing the flow of gas therethrough (e.g., a gate valve or a ball valve). The conventional valve 160 is in turn connected to the second container 120. In operation the second valve 160 is opened before the angle of repose valve 130 and closed after the angle of repose valve is closed. Therefore the angle of repose valve 130 is used to control the flow of granules 102 from the first container 110 into the second container 120, while the conventional valve 160 is used to prevent the flow of pressurized gas from the first container into the second container.
With reference now to
As best seen in
As shown in
The saddle 230 is rotatable by the shaft 132 between a first position where the granules 102 are enabled to flow through the angle of repose valve 130 without interference from the saddle and a second position (
Once rotated from the second position to the first position, the catch member 232 of the saddle 230 is rotationally displaced such that it does not impede the flow of granules 102 from the terminal end 222 of the first pipe 100 through the angle of repose valve 130 into the second pipe 150. In operation, the flow of granules 102 is stopped by rotating the saddle 230 back to the second position. Once the flow of granules 102 through the conventional valve 160 (
A seal 250 (
A first groove 260 is formed in a circumferential surface 262 of the opening 256 and is sized to receive a first o-ring 264 therein. The first o-ring 264 prevents the leakage of pressurized gas between the circumferential surface 262 of the opening 256 and the shaft 132. Forming the first groove 260 in the circumferential surface 262 of the opening significantly reduces the complexity of machining the groove compared to previous systems in which the groove was formed in a welded portion of the plates 208. A second groove 270 is formed for a second o-ring 272 in an inner surface 274 of the seal plate 252 that abuts the exterior surface of the housing 200 of the angle of repose valve 130 to prevent leakage of pressurized gas between the exterior surface of the housing and the inner surface of the seal plate. Forming the second groove 270 in the seal plate 252 significantly reduces manufacturing costs as the seal plate can be formed from a softer or more easily machined material than the housing 200 because the pressurized gas does not exert appreciable force on the seal plate.
The increased thickness of the plates 208 forming the housing 200, along with the first o-ring 264 and second o-ring 272, permit the pressure of the gas to be increased significantly compared to prior systems. As such, the flow of granules 102 through the angle of repose valve 130 is likewise capable of being significantly increased since the flow of granules 102 is at least partially dependent on the pressure of the gas. Moreover, the increased gas pressure also permits a process performed in the first container 110 or in another container coupled thereto to be performed at a greater rate.
With reference now to
As shown in
The sealing member 310 also has a void 344 therein that permits the shaft 132 to pass therethrough. The void 344 has a first diameter in the first portion 320 of the sealing member 310 that is slightly larger than the diameter of the shaft 132 to permit the shaft to pass through the first portion. The void 344 is also sized such that it does not appreciably impede rotation of the shaft 132. The diameter of the void 344 then increases in the second portion 330 of the sealing member 310 to accommodate a chevron seal 350 placed therein and discussed in greater below. The diameter of the void 344 in the third portion 340 may increase or decrease compared to that of the second portion 330 in order to accommodate multiple threads 346 formed on the circumferential surface of the void 344 in the third portion.
The threads 346 formed in the third portion 340 are configured to engage threads 362 disposed on an external surface of a jam nut 360 (broadly, a “compression member”) and permit the jam nut to laterally move with respect to a longitudinal axis of the void 344 upon rotation of the jam nut. For example, when the jam nut 360 is turned in a clockwise direction, it moves inward towards the housing 200. When the jam nut 360 is turned in the counter clockwise direction it moves outward away from the housing 200. Thus, when the jam nut 360 is turned in the clockwise direction its leading edge 364 acts upon the chevron seal 350 and exerts force thereon. Once the leading edge 364 contacts the chevron seal 350, additional clockwise rotation of the jam nut 360 results in additional compression of the chevron seal.
In the embodiment of
With reference now to
The jam nut is then tightened in block 420 by a first amount when the leak is detected. Tightening the jam nut by the first amount results in a force being exerted by the leading edge of the jam nut against the chevron seal that expands the chevron seal laterally between the shaft and the opening in the sealing member. This lateral expansion of the chevron seal functions to repair the leak of pressurized gas through the sealing member. Tightening of the jam nut by the first amount and the corresponding expansion of the chevron seal, while repairing (e.g., stopping) the leak, still permits rotation of the shaft such that the saddle can be rotated between the first and second positions described above.
The method then continues to block 430 where a determination is made if another leak (broadly, a “second leak”) of pressurized gas through the void in the sealing member is detected. If such a leak is not detected in block 430, the method remains at block 430 until the leak is detected. However, if such a leak of pressurized gas and/or granules is detected, the method 400 returns to block 420 where the jam nut is tightened by a second amount to exert additional pressure on the chevron seal. This additional pressure exerted on the chevron seal functions to further expand the chevron seal against the circumferential surface of the void and the shaft to repair the second leak. Even when tightened by this second amount, the chevron seal still permits rotation of the shaft such that the saddle can be rotated between the first and second positions described above.
The order of execution or performance of the operations in embodiments of the invention illustrated and described herein is not essential, unless otherwise specified. That is, the operations may be performed in any order, unless otherwise specified, and embodiments of the invention may include additional or fewer operations than those disclosed herein. For example, it is contemplated that executing or performing a particular operation before, contemporaneously with, or after another operation is within the scope of aspects of the invention.
When introducing elements of the present invention or the embodiments thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.