A vacuum valve placed between a vacuum vessel and a vacuum pump to adjust a valve opening degree using an operating fluid includes a packing mounted in a recessed groove of a piston. The packing is provided with a contact portion on a radially inner side and a contact portion on a radially outer side, and a slide-contact portion contacting with an inner peripheral surface of a cylinder. A portion between the contact portion and the slide-contact portion has a thin thickness.

A valve and seal arrangement for extended life in a positive displacement pump. The arrangement may take on different configurations. The seal may be secured within a shielding sidewall of a valve head for isolation from differential pressure during striking of the valve head at a valve seat. Additionally, the seal itself may include an axial tail for sealing off the fluid chamber below and defined by the seat prior to the striking of the valve head at the seat. Further, a horizontal flange defining a clearance of no more than about a layer of an abrasive constituent of a slurry being pumped may be utilized. That is, as opposed to, or in addition to, sealing in advance of striking, flow may be reduced to no more than a constituent layer thickness in advance of the striking. Other similarly advantageous architectural valve features may also be employed.

A leakage blocking device of a valve is disclosed. When a fluid flowing in a flow path 11 leaks through a gap between the outer circumferential surface of a valve stem bottom (21) and a bottom guide hole (31), a plug 53 of a piston 50 is pushed into a sealing oil chamber 45 by a pressure P1 of the leaked fluid acting on a bottom pressure acting surface S1 of the piston and pressurizes a sealing oil L in the sealing oil chamber 45 to a pressure P2 higher than the pressure P1 of the leaked fluid, thereby blocking leakage of fluid of the valve.

A valve device includes a body that includes flow paths, a recessed portion, and a valve chamber; an inner disk that includes an inner peripheral edge portion and an outer peripheral edge portion; a diaphragm; a first annular surface that is formed at the inner peripheral edge portion on a side facing the valve chamber; a second annular surface that is formed at the inner peripheral edge portion on a side opposite to the first annular surface and is supported by a bottom surface of the recessed portion; a first sealing portion, which is held by the first annular surface, on and from which the diaphragm is seated and separated; and a second sealing portion that is disposed between the second annular surface and the bottom surface of the recessed portion.

A valve device includes a body that includes flow paths, a recessed portion, and a valve chamber; an inner disk that includes an inner peripheral edge portion and an outer peripheral edge portion; a diaphragm; a first annular surface that is formed at the inner peripheral edge portion on a side facing the valve chamber; a second annular surface that is formed at the inner peripheral edge portion on a side opposite to the first annular surface and is supported by a bottom surface of the recessed portion; a first sealing portion, which is held by the first annular surface, on and from which the diaphragm is seated and separated; and a second sealing portion that is disposed between the second annular surface and the bottom surface of the recessed portion.

A valve comprises a base, a cover and a sealing member. The base comprises a passage structure and a retaining member; the cover comprises a corresponding retaining member and at least one hole, and the cover is movably combined with the base and switchable between a first state and a second state relative to the base; a sealing member is disposed between the passage structure and the cover. In the first state, the cover closes the passage structure by the sealing member to prevent the flow of the fluid between the cover and the base; in the second state, at least one fluid channel is formed between the cover and the passage structure and is in communication with the at least one hole, and the retaining member and the corresponding retaining member prevent the cover from being separated from the base when the cover moves relative to the base.

Servo gas valve comprising a gas inlet connection, a servo gas connection, a bleed gas connection, a valve body, and first and second valve seats. When a first section of the valve body is pressed against the first valve seat, the gas inlet connection is closed and the servo gas connection and the bleed gas connection are in communication with each other. When a second section of the valve body is pressed against the second valve seat, the gas inlet connection is opened and is in communication with servo gas connection while the bleed gas connection and the servo gas connection are not in communication with each other. The first section of the valve body is configured to allow for self-alignment of the first section of the valve body relative to the first valve seat when the first section of the valve body is pressed against the first valve seat.

A divert-air valve for a compressor of an internal combustion engine includes a flow housing with a duct, an actuator, a control body moved by the actuator to control a throughflow cross section of the duct, an armature, openings in the control body, a valve housing with a housing wall, a support ring with a ring-shaped plate and a cylinder wall, and a sealing ring which seals the housing interior with respect to a part of the duct. The armature is connected to the control body. The openings fluidically connect the housing interior to a part of the duct. The valve housing surrounds the actuator and a part of the control body. The support ring bears, via the cylinder wall, radially from the outside against the housing wall. The radial sealing ring lies axially against the ring-shaped plate and bears radially at the outside against the housing wall.

A divert-air valve for a compressor of an internal combustion engine includes a flow housing with a duct, an actuator, a control body moved by the actuator to control a throughflow cross section of the duct, an armature, openings in the control body, a valve housing with a housing wall, a support ring with a ring-shaped plate and a cylinder wall, and a sealing ring which seals the housing interior with respect to a part of the duct. The armature is connected to the control body. The openings fluidically connect the housing interior to a part of the duct. The valve housing surrounds the actuator and a part of the control body. The support ring bears, via the cylinder wall, radially from the outside against the housing wall. The radial sealing ring lies axially against the ring-shaped plate and bears radially at the outside against the housing wall.

A valve seat at least partially formed of a ceramic material for use in a fracturing pump includes a first body and a second body. The first body is configured to be inserted into a fluid passageway of the fracturing pump. The first body has an outer diameter, D1. The second body extends radially from the first body and has an outer diameter, D2, greater than the outer diameter, D1, of the first body. The second body is at least partially formed of the ceramic material.