DV/ZW

Function and Description

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-breathing and out-breathing lines of tanks, vessels, and process equipment to protect against unallowable overpressure and underpressure. The valve prevents emission losses almost up to the set pressure and prevents air intake almost up to set vacuum. It is designed in a way that if the set pressure is exceeded, the vapors are released into an exhaust pipe (e.g., vent header). If the set vacuum is exceeded, atmospheric air is pulled into the system. For structural reasons, 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 in and a commitment to 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 at 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 in-breathing will start as soon as the differential pressure between the atmospheric pressure and the tank is greater than the set pressure of the vacuum valve pallet. Due to our highly developed manufacturing technology, the tank pressure is maintained up to set pressure with a tightness that is far above the conventional standard. This feature is ensured 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 over pressure is released or the vacuum is balanced, the valve re-seats 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, resulting in stable operation of the valve pallet, optimized performance, and reduced product losses.