DV/ZW

Pressure and Vacuum Relief Valve, In-Line

The PROTEGO® in-line valve DV/ZW is a state-of-the-art pressure and vacuum relief valve with separate flange connections for use in a vent line. Typically the valve is installed in the in- and outbreathing lines of tanks, vessels and process apparatus to protect against unallowable high and low pressure. The valve prevents emission losses almost up to the set pressure and prevents air intake almost up to set vacuum. The valve is designed so that in cases in which the set pressure is exceeded the vapours are vented into a discharge pipe (e.g. vent header). When the set vacuum is exceeded atmospheric air is pulled into the system. Due to its design the vacuum valve pallet is one size smaller than the pressure valve pallet.

The device will start to open as soon as the set pressure is reached and only requires 10% overpressure to full lift. Continuous investments into research and development have allowed PROTEGO® to develop a low pressure valve which has the same opening characteristic as a high pressure safety relief valve. This “full lift type” technology allows the valve to be set just 10% below the maximum allowable working pressure or vacuum (MAWP or MAWV) of the tank and still safely vent the required mass flow. The opening characteristic of the pressure and vacuum side is basically the same. However, the inbreathing will start as soon as the differential pressure between the atmospheric pressure and the tank is greater than the set pressure of the vacuum pallet. Due to our highly developed manufacturing technology the tank pressure is maintained up to set pressure with a tightness that is far superior to the conventional standard. This feature is facilitated by valve seats made of high quality stainless steel and with individually lapped valve pallets (1) or with an air cushion seal (2) in conjunction with high quality FEP diaphragm. The valve pallets are also available with a PTFE seal to prevent the valve pallets from sticking when sticky products are used and to enable the use of corrosive fluids. After the excess pressure is discharged or vacuum is balanced, the valve reseats and provides a tight seal.

The optimized fluid dynamic design of the valve body and valve pallet is a result of many years of research work, which allow a stable operation of the valve pallet and optimized performance resulting in reduction of product losses.

Features and Advantages

• “full lift type” technology valve utilizes only 10% overpressure to reach full lift
• high performance seal reducing product loss below EPA’s 500ppm rule preventing environmental pollution
• based on 10% technology the set pressure is close to the opening pressure which results in best possible pressure management of the system compared to conventional 40%- or 100%- technology valves
• optimized flow performance, which reduces capital cost to a minimum as smaller sized valves may be used
• flange connection for discharge line
• can be installed in explosion hazardous areas
• housing designed to 150 psi (PN 10)
• maintenance friendly design

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