Storage tank for ultrapure hydrogen fluoride

Abstract

This invention relates to an ultra-pure hydrogen fluoride storage tank, specifically improving the large flange of a hydrogen fluoride storage tank suitable for the high cleanliness requirements of semiconductor processes below 3nm. The hydrogen fluoride storage tank includes a top cover, a body, a sealing gasket, a frame, and a sealing mechanism. The frame secures the circumference of the body; the body has a lining of fluorinated material such as PFA, and its opening has a lower flange; the top cover has a lining of fluorinated material such as PFA and has multiple interfaces, and its opening has an upper flange; the sealing gasket is made of fluorinated material PTFE; the upper flange has an upwardly convex lining, and the lower flange has a downwardly convex lining, forming an annular flexible material with a width B; the sealing mechanism includes the upper flange, the lower flange, and the annular flexible material, and its sealing... The function involves bolting the upper flange and the lower flange to compress the annular flexible material for planar sealing. To enhance the reliability of the sealing mechanism, this innovative patent further includes: the upper flange has a sealing ring that extends downward from the upper flange and fits tightly against the outer diameter side of the annular flexible material, and its axial height can cover the annular flexible material when tightened; when the sealing mechanism is tightened, the sealing ring provides radial support to the annular flexible material to increase the tightening pressure on the outer diameter side of the annular flexible material, and the increased and more uniform tightening pressure improves the sealing reliability.

Claims

1. An ultrapure hydrogen fluoride storage tank, comprising a top cover, a body, a liner, a sealing gasket, a frame, and a sealing mechanism; the frame is capable of fixing the circumference of the body; both the top cover and the body are made of stainless steel and each has a sealing flange; the inner surfaces of the top cover and the body are provided with a plurality of dovetail grooves for securing the liner formed on the inner surface by injected PFA or other fluorinated materials; the liner extends to the flange face of the top cover and the body to form a convex liner, through which a reliable seal can be achieved; the outer surface of the top cover has a plurality of PFA liner interfaces that communicate with the liner on the inner surface for installing solenoid valves and other devices; the body is a deep cup shape, the sealing flange on the body is a lower flange at its opening, the inner surface of the body has the injected liner, and the convex liner includes a lower convex liner connected to the lower flange; The top cover is shallow cup-shaped, and the sealing flange on the top cover is an upper flange with its opening. The inner surface of the top cover has an injection-molded liner, and the convex liner includes an upper convex liner connected to the upper flange. The sealing gasket is made of PTFE, a fluoropolymer material. The upper convex liner of the upper flange, the lower convex liner of the lower flange, and the sealing gasket constitute an annular flexible material. The annular flexible material has an annular width B, a total thickness H1, and an outer diameter D2. The sealing mechanism uses bolts to tighten the annular flexible material to achieve a planar seal, thereby withstanding the pressure difference between the pressure P1 inside the storage tank and the external ambient pressure P0. After being tightened, the total thickness of the compressed annular flexible material is H2, the compression ratio is H2 / H1, and the pressure generated on the sealing surface after being tightened is P2, where P2 > P1. The patent feature of the sealing mechanism includes: a sealing ring installed on the outer diameter side of the annular flexible material, with an inner diameter D2'. The outer diameter D2 of the annular flexible material is equivalent to the axial height H0, where H0≤H2. The inner diameter of the sealing ring is connected to the outer diameter side of the annular flexible material. When the sealing mechanism is tightened, the inner diameter of the sealing ring tightly supports the outer diameter of the annular flexible material. The outer diameter provides radial support to increase the tightening pressure and improve the sealing reliability. The axial gap s between the sealing ring and the lower flange is 0.0mm≤s≤0.2mm.

2. The ultrapure hydrogen fluoride storage tank as described in claim 1, wherein, The sealing ring is installed on the upper flange.

3. The ultrapure hydrogen fluoride storage tank as described in claim 1, wherein, The sealing ring is made of metal or rubber with a complete 3D molecular structure.

4. The ultrapure hydrogen fluoride storage tank as described in claim 1, wherein, The sealing ring is divided into two parts, which are respectively installed on the upper flange and the lower flange. The axial heights of the two parts are H0 / 2 respectively. When the sealing mechanism is tightened, the axial gap s is located between the two parts of the sealing ring.

5. The ultrapure hydrogen fluoride storage tank as described in claim 1, wherein, The sealing ring is made of fluororubber, with a width of B2 and an axial height of H01, where H01 > H0 and B2 = H01.

6. The ultrapure hydrogen fluoride storage tank as described in claim 5, wherein, The clamping pressure of the fluororubber sealing ring under pressure is equal to the clamping pressure of the annular soft material.

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