Pres-Vac
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Pres-Vac
Founded in 1952, Pres-Vac Engineering is the world’s leading supplier of high-velocity pressure/vacuum valves. With customers from all over the world, it has been supplying pressure vacuum valves and venting equipment to shipyards, naval architects and other partners on all continents.
PV-ECO valves, with new version available for dual fuel vessels with Methanol
The PV-ECO is designed for use on Chemical Carriers and Product Carriers addressing the special requirements for P/V valves. The PV-ECO is configurable to match the requirements of the yards and the owners.
It has been approved to work for long pipes, increasing the flexibility in the piping design for the yard. The PV-ECO pressure valve has an advanced patent flow control design securing that the valve has a soft opening and closing phase securing efficient operation also at low flow rates. A patented integrated dampener secures that the valve can operate non-hammering and non-oscillating on long pipes.
Compared to the previous generation Pres-Vac simplified the maintenance by reducing disassembly time by 60% by a lower number of parts. The new version available for dual fuel vessels match the need to manage the methanol, ammonia and other low carbon fuels used on Container ships, cruise vessels, tankers and offshore units.
PV VOC valves
The PV-VOC pressure valve is designed to meet the requirements that larger Crude Oil Carriers have for the P-V valves. The PV-VOC valve has a two-step opening which ensures that the opening and closing pressure is kept at the same pressure level during breathing phase (approximately about 50% of total flow capacity). This feature contributes to lowering VOC emission in all stages in the operation of an oil tanker.
Both the PV-ECO and PV-VOC are designed to minimize noise during operation. Optimized nozzle design has reduced noise level by 10-15dB compared to other designs.
PV-ECO/VOC Vacuum Valve
The vacuum valve is designed to avoid excessive pressure in the cargo tank during discharge operations.
When the tank vacuum exceeds the preset opening setting, the valve will open and let air into the tank. The valve size is carefully selected from the pump capacity (discharge rate) and VECS operations. The vacuum valve is also used as breather valve during voyage.
Gas Freeing Cover
Gas freeing onboard tankers is required for entry into cargo tanks, hot works, and inspection or washing for clean ballast tanks. Before a cargo tank can be gas freed it is required to purge the cargo tank with inert gas until the hydrocarbon gas content is below 2% by volume, in order to ensure the tank atmosphere is not in the flammable range.
Venting of toxic and flammable gas during gas freeing should be through the vessel’s approved gas freeing outlets, and therefore the exit velocity should be minimum 20m/s to carry the vapors clear of the deck. We provide both vacuum integrated gas freeing covers type as well as separate gas freeing covers approved for both IIA and IIB cargo group.
Pres-Vac supply spares and dedicated Maintenance kits useful to guarantee the best performance and to be in line with the latest Rules and Regulations.
Pres-Vac Vocon
Pres-Vac VOCON is venting system controlled by an electrical actuator maintaining the tank pressure between the set-pressure and the re-seating pressure. The VOCON system is installed on the mast riser’s bypass line and controls the vapor pressure in all the cargo tanks during voyage for direct emission control, in order to reduce VOC loss from the tanks during voyage. By controlling the pressure in the venting system, it is possible to fully control the VOC emissions. The VOCON system can be programmed to enable adjustment of the opening setting on the valve, according to what is optimal for the specific cargo.
Aircaps and Air Release / Vacuum Breaker Valves
Aircaps and Air Release / Vacuum Breaker Valves serve two purposes: tank venting and preventing water from entering the tank. Aircaps are installed on service tank air pipes. A wire mesh prevents flames from entering the tank. Pres-Vac offers the following Aircaps and Air Release / Vacuum Breaker Valves.
Onboard Test Rig
Onboard test rigs are used to verify the set-pressure after maintenance as well as to check for and measure leakage.