WV/T

Change-Over Valve

Function and Description

PROTEGO® change-over valves type WV/T are mainly used together with other valves or safety devices (e.g. PROTEGO®flame arresters) on cryogenic storage tanks and on tanks in process plants of chemical, petrochemical and pharmaceutical industries. They increase the operating safety of the technical equipment to be protected because each valve or safety device can be checked, maintained or repaired without any service break-down.

The valves mainly consist of housing (1) with flange connections DN 1 and two lateral connection elbows (3, 4) with flange connections DN 2 and the valve disc (2). If necessary it is possible to displace and turn the connection elbows. The valve seats (9, 10) are replaceable. The valve disc with metallic sealing surface is movable on the valve spindle (6). This ensures good adjustment to the valve seats even with high temperature differences. The sealing between valve disc and valve spindle is provided by an O-ring. The valve spindle is guided by bearing bushings; to the outside it is sealed by an adjustable packing (7).

The change-over valve allows the operator to block one valve or safety device at a time by operating the hand wheel (8). In normal operation the valve disc is in central position and the gas/liquid f ows through the two connection elbows. By turning the hand wheel to the stop, one of the connection elbows (3 or 4) is blocked while the other one remains open. The actual position of the valve disc can be identified from the position indicator (5) displayed on the valve spindle.

Depending on the requirements, the change-over valve in normal operation can be in mid-position or in end position: Midposition, e.g. when a high capacity of relief is required through emergency relief valves controlled in parallel, or end position, e.g. in case of flame arresters which, controlled in parallel, can be used or cleaned alternately as necessary.

Due to their design and appropriately selected materials the valves are distinguished by their high functional safety and very good flow rates. All elements that affect the function are made out of stainless steel.

Because of the variable nozzle positions the design of the PROTEGO® change-over valves WV/T facilitates connection of valves or other safety devices both with angle or straight through connection without additional adaptors.

Change-over valves of type WV/T stand out by their simple design, easy handling, the option of quick replacement of components that effect the function and consequently by their excellent availability and operational reliability. The lapped metallic sealing surfaces ensure a high degree of tightness even in low temperature ranges.

These valves are not flame transmission proof and do not refer to the European Explosion Protection Directive 94/9/EC, even if installed in explosive atmospheres. A hazard analysis (which considers the material selection and function of the device) shows that the device doesn’t have any potential sources of ignition.

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