PV-ECO: The Chemical Tanker P/V Valve

The PV-ECO is designed for use on Chemical Carriers and Product Carriers addressing the special requirements for P/V valves installed on long pipes. The PV-ECO offers: 

  • Superior performance to keep costs of the venting system down.
  • Configurability to match the requirements of the yards and owners.
    • Low cargo emissions to reduce the loss of cargo during transit. 
    • Approval to work on long pipes, increasing the flexibility in the piping design for the yard.
    • Simplified maintenance, reducing disassembly time, significantly. 
    • A fewer number of parts, lowering the maintenance cost. 

Main functions and features


  • The PV-ECO valve is designed, tested and manufactured to provide maximum safety for crew, cargo and vessel.
  • The pressure unit has been designed to ensure that the efflux velocity is always above the required minimum of 30 m/s and typically between 60-100 m/s.
  • The cone of the pressure unit has been optimized to secure vertical vapour dispersing, which combined with the high efflux velocity ensures, that gas is safely led away from the deck.
  • The PV-ECO valve has been extensively fire-tested at the world’s leading test laboratory in Germany. Tests include endurance burn testing and flash-back testing under all relevant rules.
  • The resilient seal protects against leakage and reduces emissions to virtually zero. 

Pres-Vac is ISO 9001 certified to ensure consistency of the high-quality products that Pres-Vac is known for.

Compliance with rules and regulations

  • The PV-ECO valve is designed, tested and manufactured to comply with all existing and foreseen international regulations.
  • The European Commission adopted EN ISO 16852:2016 as a new standard for testing of flame arrestors to be installed onboard marine vessels.  As the first P/V valve on the market, The PV-ECO valve has been designed, tested and approved to comply with this new standard.
  • Flashback testing at low flow rates following EN ISO 16852:2016. The flashback tests shall be performed on pipe lengths equal to or longer than the pipe length, on which the valves are to be installed. This is mandatory according to EN ISO 16852:2016. 

Effective relief of tank pressure

The PV-ECO valve provides effective control and management of the tank pressure. If the pressure exceeds the specified opening pressure, the valve will open immediately and relieve the excess pressure. Similarly, if pressure during discharging gets below the specified opening pressure, the valve will open and relieve the vacuum. The PV-ECO valve has an advanced flow control design to manage tank pressure:

  • The tank pressure valve is controlled by a combination of magnet and weight forces to secure that the valve does not create a pressure surge during the opening.
  • A patented combination of a booster plate and pressure control ring secures that the valve has a soft opening and closing phase securing efficient operations also at low flow rates.
  • A patented, integrated dampener secures that the valve can operate non-hammering and non-oscillating also at long pipe lengths.

High closing pressure

The patented new flow control system secures that the PV-ECO valve has a very high closing pressure reducing blowdown to 5-6 kPa. This means substantial reductions in loss of inert gas and cargo vapour compared to other P/V valves. 

Low noise level

The PV-ECO valve is designed to minimize noise during operations. By optimizing the nozzle design, the noise level of the PV-ECO valve has been reduced by 10-15 dB compared to other designs. In many applications, hearing protection will not be required. 

Additional features

The PV-ECO valve has been made easier to maintain by the following features:

  • The number of parts has been reduced by 30 % and the valve is very simple to disassemble and maintain.
  • The weight of the valve has been significantly reduced.
  • Check lift can be maintained without disassembly of the valve.
  • Easy calibration of setting after over-haul
  • Regular maintenance can be performed by onboard crew.
  • Replaceable vacuum flame arrestor and replaceable gas freeing cover screen arrestor
  • The integrated resilient seat can be replaced and reduces disc/seat wearing to zero. 

Configured to your requirement

Pres-Vac P/V valves are individually configured to suit your specific requirements:

  • 9 different sizes of pressure units combined with 7 different sizes of vacuum units
  • Variable flange size
  • All flange standards available
  • Optional integrated gas freeing cover
  • Options include electric heating, coating and high-pressure dual valves
  • Two different product versions

Operations and maintenance made simple

The PV-ECO valve has been designed to simplify operation and maintenance. Daily operations by the crew are made simple by the following features:

  • New two-way operating full stroke check lift
  • Visual inspection of all moving parts
  • Dirt indicator
  • Hinged type gas freeing cover


Specific requirements

The PV-ECO valve is always configured to meet the specific requirement of every single customer. Different vessel designs need different venting requirements for pressure and vacuum valves. Furthermore, vessel designs tend to use different piping arrangement and consequently require different flange sizes and flange standards.

The pressure side of the valve can be delivered in four different sizes and the vacuum side can be delivered in three different sizes. The pressure and vacuum sides can be freely combined to deliver the combination most suitable for your vessel. All the combinations can be delivered in different flange sizes and with all flange standards.

Furthermore, Pres-Vac offers a broad range of options for the PV-ECO valve:

  • integrated gas freeing cover
  • electric, steam or thermal heating
  • custom coating
  • high-pressure dual valve

Custom solutions and special requirements can be delivered upon request.

Option: Integrated gas freeing cover

  • The gas freeing cover is installed as an integrated version on top of the vacuum valve.
    It can easily be operated without using any tools.
  • The design is made in a way that the cover releases the maximum amount of vapour that the size of the piping allows.

Option: Compliance with OCIMF, 10% requirement

  • The vacuum valve can be designed to meet the OCIMF requirement of max 10% vacuum increase below set point. 

Option: Electric, steam or thermal heating

  • The pressure unit and the vacuum unit can be equipped with a heating device. This prevents ice accretion*, which will result in malfunction. The heating will also prevent certain cargoes with a high pour point from crystallizing, as the temperature can be kept at a suitable level.

*Ice accretion occurs when waves or heavy rain is present with surface temperatures at or below freezing. A layer of ice will accumulate and prevent the valve from functioning properly.

Option: Custom coating

  • As a standard, the PV-ECO is delivered in stainless steel without coating. However, it is possible to deliver the PV-ECO valve in any colour.

Option: High-pressure dual valve

  • The valves can be delivered with a high-pressure unit for special chemical applications or high-pressure requirements to reduce vapour emissions. The valves can be adjusted for specific needs.


The PV-ECO valve is available in two different versions:


You should choose a PV-ECO Ultimate if you are particularly concerned about leakage protection, loss of inert gas, disc/seat and flame screen maintenance costs.

The PV-ECO Ultimate delivers all the features of the PV-ECO Superior and three additional safety and maintenance features:

  • Seat with integrated resilient seal.
    • The integrated resilient seal provides ultimate leakage protection and also reduces wearing of disc and seat.
  • Flame screens in AISI 316 L stainless steel.
    • To reduce wear from high corrosive cargoes and to extend maintenance intervals, flame screens are delivered in AISI 316 L stainless steel.


You should choose the PV-ECO Superior if your focus is to get a safe and very reliable P/V valve of high quality.

Main features:

  • Optimal safety
  • Compliance with all current rules and regulations
  • Low noise
  • High blowdown
  • Simple operations and maintenance

Resilient seal

  • Elimination of leakage
  • Reduction of wear and tear
  • Easy replacement
  • Made of advanced, non-flammable material.
  • Suitable for chemical and oil products


Maximum safety for crew, vessel and cargo

  • High vertical gas dispersion
  • Low noise
  • Extensively tested by the independent test laboratory
  • Integrated leakage protection (Ultimate version)

Compliance with all current and foreseen regulations

  • No risk of non-compliance
  • Complies with the latest European standard for fire testing

Designed to your needs

  • The valves can be optimized to effectively meet your venting requirements.

Excellent operational performance

  • The combination of weight and magnetic force protects against pressure surges and secures high closing pressure.
  • Leakage protection ensures maximum safety, minimises loss of inert gas and cargo vapour.

Low maintenance costs

  • The modular design of the valve makes the replacement of wear parts and spare parts simple.
  • Lifetime availability of spare parts and a global network of service centres.

Emission Reduction

  • High closing pressure


  • Pres-Vac Engineering A/S
    Solvang 22
    3450 Allerød