UB/VF

Function and Description

The PROTEGO^® UB/VF diaphragm valve is a worldwide unique vacuum relief valve combining the function of a dynamic and static flame arrester. It is primarily used as a device for flame transmission-proof in-breathing on tanks, containers, and process equipment. The valve offers reliable protection against vacuum build up, prevents the in-breathing of air and product losses almost up to the set vacuum, and protects against atmospheric deflagration. The PROTEGO^® UB/VF diaphragm valve has proven itself over many years under a wide variety of operating conditions in the mineral oil and chemical industries. Worldwide, it is the only vent which works reliably with problem products such as styrene or acrylates. The set vacuum is adjusted with a freeze resistant water-glycol mixture which ensures safe operation under extreme cold weather conditions. The PROTEGO^® UB/VF valve is available for substances from explosion group IIB3.

If a vacuum builds up in the tank, it is transmitted through pressure balancing tubes into the vacuum chambers (1), (2), which are connected to each other. This will remove the weight of the load liquid, and the atmospheric pressure will lift the diaphragm (3) off the inner and outer valve seat rings (4, 5), resulting in ventilation of the tank. The vacuum setting is adjusted via the filling level of the load liquid and can be checked by a floating level indicator (6).

The tank vacuum is maintained up to the set vacuum with a tightness that is above the normal standards due to our highly developed manufacturing technology. This is achieved by the liquid loaded diaphragm pressing tightly around the special designed valve seat surface area even when the operating vacuum increases, which reduces surface pressure and unnecessary leakage. After the vacuum is balanced, the valve re-seats and provides a tight seal.

At very low vacuum settings, the explosion pressures resulting from an atmospheric deflagration may be strong enough to lift the diaphragm off the valve seat rings. The ignition into the tank can be prevented by installing the PROTEGO^® flame arrester unit (7). This PROTEGO^® flame arrester unit provides additional protection against atmospheric deflagration when the valve is open for maintenance and inspection.

The valve can be used at an operating temperature of up to +60°C/ 140°F and meets the requirements of European tank design standard EN 14015 (Appendix L) and ISO 28300 (API 2000).

Type-approved in accordance with the current ATEX Directive and EN ISO 16852, as well as other international standards.