Wenzhou, China
Wenzhou, China

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Patent
Zhejiang China Valve Co. and Xu | Date: 2011-10-12

A sealing microsawtooth ring joint, made between a toothed seating surface and a full plain seated surface by a microsawtooth ring with its tooth crest on the seating surface being a cutting edge whose corner or whose crest angle is about 90~120, with its tooth height Z_(t) being about 10~20 times the roughness R_(a) of the seated surface, and with the ratio of its tooth pitch X_(s) to its tooth height Z_(t) being 20~500 to ensure that the tight joint has a microcosmic line contact followed by a surface contact or to ensure that the tight joint has both such a line contact as to be able to provide a necessary seating stress locally and such a surface contact as to be able to protect the line contact from being excessively pressed to get blunt or disappeared, can be used either as a pressure-tight joint or as a self-energizing tight joint of any two surfaces such as flats to flats, cones to cones or spheres, spheres to spheres or cones etc., thus simplifying and unifying the designing, calculating, manufacturing, selecting, installing and maintaining of fussy gaskets for a tight joint of flat surfaces, avoiding the lapping of formed jointing surfaces without using soft gaskets, increasing the reliability of tight joints and the utilizing coefficient of natural resources. The sealing microsawtooth ring joint can still have an extra sealing reliability and safety sensation by selectively adding one of four basic gland seals.


Patent
Zhejiang China Valve Co. and Xu | Date: 2011-10-12

A gland seal designed according to the joints factors m and y and the seal-designing rule refined from ASME Code to result in its minimum necessary seating stress y at no fluid pressure being so small to be ignorable that its seeing maintenance factor or disturbance resistance index m, equal to the joints sealing actuation force divided by the joints unseating actuation force, can be used to indicate its sealing safety at a fluid pressure: when in = 1, its sealing actuation force equals its unseating actuation force or equals its seating area x fluid pressure and so it can be kept leak-free under no upset disturbance condition and may leak at an upset moment, and when m > 1, it can be resistant to an upset disturbance and be the greater, the more resistant. The factor m for a self-energizing tight joint is equal to its fluids sealing actuation area divided by its fluids unseating actuation area.


It is inevitable for the tight closure of a ball valve to be disturbed by its balls wedging action, and its ball seat is an upset impulse amplifier with an inherent disturbance resistance index or a sealing maintaining factor m. The ball valve seat designed with equilateral triangle section methods of the invention can positively ensure itself a resistance to ball-wedged disturbance from eccentric drive to make a hall valve realize its tight closure by the floated pressure of balls or seats onto each other and ensure that the ultimate rotational resistance to the ball only relates to the ultimate pressure from/on one seat. Because the seat of the prior art can not ensure balls or seats against each other a floated pressure sufficient to resist to the ball-wedged disturbance from eccentric drive, the tight closure of the ball valve has to be realized by either larger preclamping force or larger spring preload between seats and balls so as for the ultimate rotational resistance to balls to be from larger ball-clamping forces from two seats. Therefore, the ball valve in accordance with the invention is a real floating or mounted ball valve, whose operation torque can be at most half of that of a formal or false floating ball valve of the prior art.


Patent
Zhejiang China Valve Co. and Xu | Date: 2011-07-13

A stem shoulder seal with double rings is composed of a sealing ring, a clamping ring and a spherical or conical stem shoulder, and the sealing ring is of a self-energized seal designed to its ultimate allowable strength and automatically free of any load beyond its ultimate strength. An assembly of independent dual stem seals, consisting of a stem shoulder seal with double rings, a stem cylinder seal with triangular sections and an isolating mating, can ensure that a stem has three seals which get well seated automatically at the same time to bear an identical ultimate medium pressure independently or without any mutual interference in service when assembled to the extent that the stem operating torque is just definitely increased, thereby ensuring that a stem sealing has a triple safety.


Xu C.-X.,Zhejiang China Valve Co.
Petrochemical Equipment | Year: 2014

A leakage for fluid in a pressure vessel to flow through its sealing joint to atmosphere is just like a leakage for electric charges in a capacitor to flow through its insulator to ground, and hence there is a sealing law for pressure vessels that is completely similar to Ohm's law, stating the leakage current JL flowing through a sealing joint of pressure vessels is directly proportional to the pressure difference p between its ends and inversely proportional to its leak resistance RL , or IL = p/R L. Thus, it can be known according to the sealing law that the tightness or leak resistance (RL= p/IL= pt/O is the product of pressure p and time t expended by a full leaking of a u-nit cubage of fluid through sealing joints under a certain fixed pressure p and can be determined according to RL = (p2Hr)/(ΔpC) , and the greater the value of p/Δp, the shorter the time required to observe, or the closer to being done at a constant pressure and temperature the test, and the more accurate the test result, where p is the test pressure, Hr is the time expenditure for a pressure drop from p to p - Δp, C is the test fluid cubage.


Xu C.-X.,Zhejiang China Valve Co.
Petrochemical Equipment | Year: 2013

The difficulty for a sealing element to create and maintain a leak-free joint is determined by its sealing difficulty coefficient m1[elastic modulus (Ec) of its sealing contact layer/elastic modulus (E c) of its sealing contact layer substrate]. Therefore, ideally the contact layer of a sealing element shall be soft & inelastic and assembled up to its fully yielded deformation to provide a contact layer with a lower value of elastic modulus (Ec), and the contact layer substrate shall be strong elastic and assembled up to its fully elastic deformation to provide a contact layer substrate with a higher value of elastic modulus (Es). It is the most difficult for a rubber sealing element to create a leak-free joint because its Ec = Es, and it is far easier for a metal sealing element than for a rubber sealing element because the metal sealing element can be designed and coated to cause its Ec>E s.


Xu C.-X.,Zhejiang China Valve Co.
Petrochemical Equipment | Year: 2013

Sealing needs a sealing surface that has microcosmic irregularities fully complementary to a surface to be sealed and that can be qualified only by a compressive working in position. ASME Code ignores the working stress needed to result in a qualified gasket in installation for the stress needed to enable a qualified gasket to function well or maintain its leak-free joint, and only considers the influence of the sealing material's strength but never its elasticity. Undoubtedly, ASME Code's sealing maintenance factor m and minimum necessary sealing stress y of gaskets are both wrong in values. Similarly, so are the gasket parameters system substituted for the gasket factors m and y in PVRC and EN 13555. Actually, the stronger the strength and the elasticity of a sealing contact layer, the more difficult for its sealing element to create or maintain a fully deformed contact; whereas the stronger the strength and the elasticity of a contact layer substrate, the easier for its sealing element to create or maintain a fully deformed contact; i. e. the index used to measure the difficulty for a sealing element to create or maintain a leak-free joint is its sealing difficulty coefficient m1 - Ec(its contact's elastic modulus) / Es(its substrate's elastic modulus) ; so it is the most difficult for a rubber element to create or maintain a leak-free joint because of its m1=1, the easiest for a grease element because of its m1 = 0, and easier for the other sealing elements than for a rubber element because their m1 can be smaller than one (or m 1<1) by designing and coating.


Patent
ZHEJIANG CHINA VALVE Co. | Date: 2014-03-21

A sealing microsawtooth ring joint, made between a toothed seating surface and a full plain seated surface by a microsawtooth ring with its tooth crest on the seating surface being a cutting edge whose corner or whose crest angle is about 90120, with its tooth height Z_(t )being about 1020 times the roughness R_(a )of the seated surface, and with the ratio of its tooth pitch X_(s )to its tooth height Z_(t )being 20500 to ensure that the tight joint has a microcosmic line contact followed by a surface contact or to ensure that the tight joint has both such a line contact as to be able to provide a necessary seating stress locally and such a surface contact as to be able to protect the line contact from being excessively pressed to get blunt or disappeared, can be used either as a pressure-tight joint or as a self-energizing tight joint of any two surfaces such as flats to flats, cones to cones or spheres, spheres to spheres or cones etc., thus simplifying and unifying the designing, calculating, manufacturing, selecting, installing and maintaining of fussy gaskets for a tight joint of flat surfaces, avoiding the lapping of formed jointing surfaces without using soft gasket, increasing the reliability of tight joints and the utilizing coefficient of natural resources. The sealing microsawtooth ring joint can still have an extra sealing reliability and safety sensation by selectively adding one of four basic gland seals.


A stem shoulder seal with double rings is composed of a sealing ring, a clamping ring and a spherical or conical stem shoulder, and the sealing ring is of a self-energized seal designed to its ultimate allowable strength and automatically free of any load beyond its ultimate strength. An assembly of independent dual stem seals, consisting of a stem shoulder seal with double rings, a stem cylinder seal with triangular sections and an isolating mating, can ensure that a stem has three seals which get well seated automatically at the same time to bear an identical ultimate medium pressure independently or without any mutual interference in service when assembled to the extent that the stem operating torque is just definitely increased, thereby ensuring that a stem sealing has a triple safety.


Patent
ZHEJIANG CHINA VALVE Co. | Date: 2014-03-21

A sealing microsawtooth ring joint, made between a toothed seating surface and a full plain seated surface by a microsawtooth ring with its tooth crest on the seating surface being a cutting edge whose corner or whose crest angle is about 90120, with its tooth height Z_(t )being about 1020 times the roughness R_(a )of the seated surface, and with the ratio of its tooth pitch X_(s )to its tooth height Z_(t )being 20500 to ensure that the tight joint has a microcosmic line contact followed by a surface contact or to ensure that the tight joint has both such a line contact as to be able to provide a necessary seating stress locally and such a surface contact as to be able to protect the line contact from being excessively pressed to get blunt or disappeared, can be used either as a pressure-tight joint or as a self-energizing tight joint of any too surfaces such as flats to flats, cones to cones or spheres, spheres to spheres or cones etc., thus simplifying and unifying the designing, calculating, manufacturing, selecting, installing and maintaining of fussy gaskets for a tight joint of flat surfaces, avoiding the lapping of formed jointing surfaces without using soft gaskets, increasing the reliability of tight joints sod the utilizing coefficient of natural resources. The sealing microsawtooth ring joint can still have an extra sealing reliability and safety sensation by selectively adding one of four basic gland seals.

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