Valve unit

A sealing element for use in a valve unit, the valve unit comprising

• a) a valve housing having a process pressure input line, a process pressure output line and a process guide shaft,
• b) an operating piston for closing and opening a connection between the process pressure input line and the process pressure output line,
• and
• c) at least one control line and at least one control chamber for controlling the operating piston,
• wherein the operating piston can be displaced in the axial direction within the process guide shaft in a sealed manner by means of a dynamic process seal and
• wherein the operating piston has a closing ring which in the closed state of the connection sealingly abuts a valve seat of the valve housing,
• wherein the valve seat consists of a softer and more elastic material than a circumferential sealing edge abutting said valve seat,
• and
• wherein the sealing element is an annular sealing element which comprises the valve seat is present,
• wherein the valve seat is embedded in a valve seat ring arrangement, wherein the valve seat ring arrangement consists of a harder material than the valve seat,
• wherein the valve seat ring arrangement has an inner valve seat ring and an outer valve seat ring,
• wherein the sealing element has the shape of a truncated cone with an outwardly widening base,
• wherein the sealing element is retained between the inner valve seat ring and the outer valve seat ring,
• wherein the base can be clamped between the inner valve seat ring and the outer valve seat ring, a side of the base being opposite the truncated cone lying on a first outer surface of the inner valve seat ring,
• wherein a free end of the truncated cone of the sealing element can be located in a freely accessible manner between the inner valve seat ring and the outer valve seat ring and can form the valve seat,
• wherein the truncated cone comprises an inner surface against which a second outer surface of the inner valve seat ring can lie,
• wherein the truncated cone comprises an outer tapered flank against which an inclined inner surface of the outer valve seat ring lies,
• and wherein the closing ring is the circumferential sealing edge.

An operating piston of a valve unit,

• the valve unit comprising
• a valve housing having a process pressure input line, a process pressure output line and a process guide shaft,
• a foot element or a head element fixed relative to the valve housing, the foot element or the head element having a circumferential sealing ring forming a dynamic control seal when the piston is moved,
• the operating piston for closing and opening a connection between the process pressure input line and the process pressure output line,
• and
• at least one control line and at least one control chamber for controlling the operating piston by using a control pressure,
• wherein the operating piston comprises a base body with a receiver opening,
• wherein the receiver opening comprises an inner wall to sealingly receive the foot element or the head element, the control chamber being sealed by the circumferential sealing ring of the foot element or the head element, wherein the receiver opening thereby forming the control chamber, wherein a bottom of the receiver opening forms a first control surface, and
• wherein the control pressure acts on the first control surface for controlling a movement of the operating piston.

A valve unit, comprising

• a) a valve housing having a process pressure input line, a process pressure output line and a process guide shaft,
• b) an operating piston for closing and opening a connection between the process pressure input line and the process pressure output line,
• and
• c) at least one control line and at least one control chamber for controlling the operating piston,
• wherein the operating piston can be displaced in the axial direction within the process guide shaft in a sealed manner by means of a dynamic process seal and
• i) wherein the operating piston has a closing ring which in the closed state of the connection sealingly abuts a valve seat of the valve housing, or
• ii) wherein the valve housing has a closing ring which in the closed state of the connection sealingly abuts against a valve seat of the operating piston,
• wherein the valve seat consists of a softer and more elastic material than a circumferential sealing edge abutting said valve seat,
• and
• wherein an annular sealing element which comprises the valve seat is present,
• wherein the valve seat is embedded in a valve seat ring arrangement, wherein the valve seat ring arrangement consists of a harder material than the valve seat,
• wherein the sealing element has the shape of a truncated cone with an outwardly widening base
• and wherein the closing ring is the circumferential sealing edge,
• wherein the operating piston has a base body with a U-shaped longitudinal section and a piston ring,
• wherein the base body forms an upwardly open first receiver,
• wherein a fixed foot element is configured on the valve housing,
• wherein the foot element engages in the first receiver, wherein the first receiver forms the first control chamber,
• wherein the valve housing forms an annular gap around the piston ring,
• wherein the annular gap forms the second control chamber and
• wherein the circumferential sealing edge is configured on the piston ring.