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Valve Structure Introduction

A valve structure includes a valve body on which is mounted a first valve and a second valve. The first valve traverses the valve body at a first position and the second valve traverses the valve body at a second position spaced apart from the first position. The first valve may comprise a fill valve and the second valve may comprise a pressure relief valve. Alternatively, a single valve structure may incorporate both the fill and pressure relief functions. The valve structure may be incorporated with a bladder made of a flexible and elastic material. In this arrangement, the valve body is positioned in a valve receiving opening in the bladder material and is sealed to the bladder material around the periphery of the valve receiving opening so as to define a sealed bladder interior with the bladder material. Such a valve and bladder combination may be used together with a hull tube to form a portion of an inflatable hull for a boat.

Valve positions are operating conditions determined by the position of the disc or rotor in the valve. Some valves are made to be operated in a gradual change between two or more positions. Return valves and non-return valves allow fluid to move in 2 or 1 directions respectively.

One-port valves

One-port valves, which can only allow the fluid to move along the pipe or stop it from moving. These valves cannot direct the fluid in a specific pipe. but in some instances can change the speed at which the fluid is moving. An example would be the valve used in a kitchen tap.

Typical applications in temperature control: To control the flow of primary heating fluid, whether steam or
hot water, to provide constant secondary temperature; Pressure control:To control steam, water or air distribution lines at
precise operating levels; Flow control: Used in conjunction with flowmeters to accurately
control the flow of steam, gases or liquids; Thermal oil control: Thermal oil is sometimes used as
the primary heating medium.

Two-port valves

Two-port valves do a similar job, but the flow can go in either direction between two ports.Operating positions for 2-port valves can be either shut (closed) so that no flow at all goes through, fully open for maximum flow, or sometimes partially open to any degree in between. Many valves are not designed to precisely control intermediate degree of flow; such valves are considered to be either open or shut. Some valves are specially designed to regulate varying amounts of flow. Such valves have been called by various names such as regulating, throttling, metering, or needle valves. for example needle valves. Usually a mechanism or flow metre will be used to indicate by how much the valve is open.

Three-port valves

A three port valve construction having a onepiece plastic valve housing body provided with a stepped cylindrical opening through one end thereof that defines a pair of spaced annular shoulders, the body having three ports therein transversely disposed to the opening and respectively intersecting with the opening with one port being located between the shoulders and the other two ports being respectively disposed outboard of the shoulders. One of the shoulders defines a first valve seat and an annular plastic valve seat member is ultrasonically welded to the other of the shoulders to define a second valve seat. An axially movable valve member is slidingly disposed in the opening to control the first and second valve seats.

Four-port valves

A four-port valve which has four ports and in which directions of the flow of fluid passing through the ports provided on the two opposed positions are fixed and the other two ports provided between said ports are selectively communicated with either of said two ports in a casing to change over the fluid passing through the ports, the four-port valve characterized in that: the inside of the casing is divided into four chambers by a substantially-X-shaped partition wall; the opposed two of the four chambers are determined as fixing chambers communicating with the ports respectively connected with two types of passages in which directions of the flow of fluid are fixed while the remaining two opposed chambers are determined as change-over chambers communicating with the ports respectively connected with two types of passages in which directions of the flow of fluid are alternately changed over; valve openings for communicating two chambers adjacent to the substantially-X-shaped partition wall with
each other as provided; a valve plate for closing the valve openings and a drive shaft for supporting and oscillating the valve plate are provided to one among the four chambers while a valve plate for closing the valve openings is provided to the opposed chamber so as to be connected with the valve plate supported by the drive shaft by a semi-circular or circular connecting ring piercing through the valve openings; and the valve plate oscillating by rotation of the drive shaft is interlocked with the other valve plate to alternately communicate the two fixing chambers with the different change-over chambers.

It can be used to isolate and to simultaneously bypass a sampling cylinder installed on a pressurized water line. It is useful to take a fluid sample without affecting the pressure of a hydraulic system and to avoid degassing (no leak, no gas loss or air entry, no external contamination).

Five Valve Mainfolds

Five valve mainfolds consists of two shut off valve,two equalizing valves and a single vent valve which takes the place of the conventional piped up 5-valve manifold generally found on field meters or gas service differential pressure instrument. The five valve mainfold are designed for natural gas application.

six port loop inject valve

With the valve in the load position the sample can be injected into the sample loop while the mobile phase is pumped directly through to the column. When the valve is switched to the inject position, the pump is then connected to the sample loop and the sample is carried onto and through the column. The ‘sample in’ and ‘waste’ ports are joined but isolated from the loop. It is suggested that ports are connected to the corresponding lines as shown. This ensures that the flow of the mobile phase is in opposite directions during the load and inject operations.

ten port loop inject valve

This valve allows alternate injection from two different sample loops, either identical or of different sizes. This application can alternatively be satisfied with a 4 port switching valve and a 6 port loop inject valve. 10-port gas sampling valves can easily be plumbed to replicate the function of the simpler valves, while offering many other possible configurations. SRI offers standard plumbing configurations, including: Inject Only, Inject and Backflush, Precolumn Backflush to Vent, Column Sequence Reversal, Alternate Loop Inject, and Dual Loop-Dual Column. Many more plumbing configurations are possible, especially when multiple valves are plumbed together.

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Article Summary

this article mainly talks about the structure of types of valve.

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