A valve configured to control a flow of a process fluid includes a pair of packing seals separated by a seal gap space along a linear valve stem of the valve, and a pressurization port that can be used to apply a pressurizing fluid, such as nitrogen gas, to the seal gap at a gap pressure that is higher than the process fluid pressure, thereby ensuring that any leakage past the packing seals will be of pressurizing fluid into the process fluid and/or into the environment, and that no process fluid will escape into the environment. The pressure or flow rate of the pressurizing fluid can be monitored to detect and quantify any pressurization fluid leakage past either of the packing seals, so that a maintenance action can be applied to the valve, such as re-tightening or replacing at least one of the packing seals, or replacing the valve.

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 piston and cylinder assembly structured to reduce breakaway friction (stiction) upon movement of the piston within the cylinder. The assembly includes a cylinder housing, a piston having a piston crown with a top face and one or more peripheral grooves, and an O-ring positioned on the piston in each of the one or more peripheral grooves. The piston crown incorporates one or more passageways extending from a space above the piston to a location within the peripheral groove inside of (behind) the O-ring. An increase in a volume of fluid in the chamber above the piston directs fluid through the passageways into the peripheral groove, thereby pressing the O-ring against the cylinder wall. A double acting piston embodiment uses at least two O-rings positioned within at least two grooves, each with associated fluid flow passageways into the grooves behind the O-rings.

In a valve (10) having a pneumatic or hydraulic drive unit (20), the drive unit (20) includes a cylinder (22), a piston (24), a spindle unit (26) mounted for axial movement in the cylinder (22), and a housing cover (28), the piston (24) dividing the interior of the cylinder (22) into a cover-side space (42) and a valve seat-side space (40), and a duct (66) within the spindle unit (26) leading to the valve seat-side space (40). Formed in the housing cover (28) are a fluid intake (44) and a fluid exit (46) as well as a pressure fluid duct (48) in fluid communication with the fluid intake (44) and an outlet duct (50) in fluid communication with the fluid exit (46). The pressure fluid duct (48) branches into two partial ducts (54, 56), a first partial duct (54) extending through the spindle unit (26) into the valve seat-side space (40) and opening out there, and a second partial duct (56) opening out into the cover-side space (42), and a closure body (68) being provided which seals either the first partial duct (54) or the second partial duct (56) in a fluid-tight manner. Furthermore, a modular system (70) and a method for manufacturing valves (10) are indicated.

The present disclosure discloses an oil-retaining mechanism, a valve structure, and a water outflow device. The oil-retaining mechanism comprises a valve body, a valve shaft, and a sealing member. The valve body comprises a motion cavity. The valve shaft is disposed in the motion cavity and configured to move axially. The sealing member is disposed between a cavity wall of the motion cavity and the valve shaft. At least one of the cavity wall of the motion cavity, the sealing member, or a connection portion of the motion cavity, the sealing member, and the valve shaft extends inward to define an oil storage groove. The oil storage groove comprises an opening. An inner side of the opening stores lubricating oil. The opening cooperates with and contacts the outer circumferential surface of the valve shaft. When the valve shaft moves in the motion cavity, the lubricating oil lubricates the valve shaft.

Seal assemblies for use with fluid valves are described. An example apparatus includes a cage; a plug including a seal gland; and means for sealingly engaging an inner surface of the cage at least partially positioned in the seal gland and including a first portion and a second portion, in response to a fluid acting on the first portion in a first direction, the first portion to engage, outwardly urge, and splay the second portion to sealingly engage the cage, in response to the fluid acting in a second direction, the second portion to deter the fluid from acting on the first portion, the first direction opposite the second direction.

A sealant gun is inserted into a limited space work area to engage a buttonhead fitting supported by a fitting assembly perpendicular to a valve stem extending from a tapered plug valve. The fitting assembly orients the buttonhead fitting on the valve stem for movement of the sealant gun in a single vertical direction to engage the buttonhead fitting. The sealant gun injects a sealant under pressure through the buttonhead fitting and the valve stem into a tapered bore of the valve body. The tapered bore receives a tapered plug on the end of the valve stem for movement into and out of a closed valve position with the tapered bore. The sealant is injected between the tapered plug and the tapered bore to provide a seal therebetween that prevents the escape of the fluid flowing through the valve from the valve through the valve stem to the atmosphere.

An electric valve and an assembly method therefor. The provision of multilayered sealing of a first sealing element, a second sealing element, and a sealing medium located between the first sealing element and the second sealing element along the axial direction of a valve stem is conducive to restricting outward leakage of a fluid along the axial direction of the valve stem.

A seal assembly for a valve stem comprises an external seal placed on a valve stem facing an external environment; an internal seal placed on the valve stem facing a process environment; the external and internal seals define a chamber for the containment of barrier fluid; the chamber has an inlet configured to be placed into fluid communication with a source of barrier fluid; a detector of the amount of barrier fluid; a pressurizer device for providing the chamber with a positive pressure with respect to the process environment; the pressurizer device is configured to be installed coaxially with the valve stem.

A two-piece valve shell (body and bolted-on top bonnet) structure reduces possible leakage paths while also providing a top-side ball/stem installation/removal path (when the bonnet piece is not present) to facilitate initial valve assembly as well as subsequent inspection/removal of the ball/stem and other valve internals for conducting valve maintenance without requiring the valve body to be removed from its process connections. Internal wetted valve surfaces are coated with tantalum to provide a tantalum ball valve suitable for use as a sulfuric acid feed valve in severe high-temperature high-pressure industrial processes such as HPAL processes. Sealing cavities created by spaced-apart body-to-bonnet and/or stem-to-bonnet sealing structures can be inertly pressurized to hermetically isolate the sealing structures from ingress/leakage of corrosive process materials.