Tank Protection System

NEOTECH KOREA was founded in 1999, since then we have been studying every aspect of tank protection system and developing several methods ranging from field application to new products for higher safety standard. Every effort is made to ensure the quality of products meet the needs of customers, through continuous technical development. NEOTECH specialized in the manufacture of pressure and vacuum relief valves and flame arresters, as well as safety protection devices for liquid petroleum and petroleum products storage tanks, treatment, nitrogen blanketing systems for automatic nitrogen sealing devices, explosive venting systems, and other related products.

All NEOTECH KOREA products are designed, manufactured and tested in accordance with API 2000, API 650, API 2521, API RP 520, EN12874, BS 7244 and other relate recognition code or purchase order specification. Our environment & quality management systems have been assessed and certified by BVQi Quality Evaluation Inc. of France.  All the range of products are manufactured in accordance with the requirement of ISO14001:2004 Environment & ISO 9001:2000 quality assurance procedures and assessed under strict quality standards before delivery to our customers.

T Energy Industries is the strategic partner of NEOTECH KOREA in Malaysia and Indonesia. We promise to do our best to give our customers satisfaction, from niche engineering to perfect after-sales service.

Pressure Vacuum Relief Valve 


Pressure / Vacuum relief valves are used on liquid storage tanks and other process vessels or systems to prevent structural damage due to excess internal vacuum. Storage tanks are pressurized when liquid is pumped in, compressing the existing vapor or when rising temperatures cause increased evaporation or expansion of existing vapor. Vice versa, a vacuum condition may be created when pumping out or due to falling temperature. To prevent tank damage, vapor must be allowed into or out of the tank at specified vacuum condition. The volume rate of venting depends upon the tank size, volatility of the tank contents, the pumping rates and the temperature. 

Why PVRV Is Required? 

Without an opening or a controlled opening, a fixed roof atmospheric tank would rupture under increasing pressure caused by pumping liquid into the tank or as a result of vapor pressure changes caused by severe thermal changes. Imploding, or the collapsing of a tank, occurs during the pumping out procedure or thermal changes. As the liquid level lowers, the vapor space pressure is reduced to below atmospheric pressure. The PVRV can be weight-loaded or spring-loadedFlow through the valve is controlled by the weight of the pallet or the spring force acting on the pallet to lift or lower the pallet. 

Types of PVRV 

Type Description Picture
Pressure Relief ValveAs the pressure in the storage tank increases.

When the set pressure is reached, the pressure pallet lifts and relieves to atmosphere.

Weight / Spring loaded.
Vacuum Relief Valve As a vacuum is drawn in the storage tank (for example, when fluid is being pumped out).

When the vacuum setting is reached, the pallet lifts and air is drawn in the storage tank from the atmosphere.

Weight / Spring loaded.
Pressure Vacuum Relief Valve Combination of feature from both pressure and vacuum relief valve.

Weight / Spring loaded configuration for both sides can be customized.
Pressure Vacuum Relief Valve with Flame Arrester Pressure vacuum relief valve with an In-line deflagration flame arrester.

The combination units are used for pressure vacuum relief where low flash point flammable vapors must be piped away.

The bank assemblies are designed of wafer design for easy removal from the housing to facilitate inspection and cleaning.

Sizing of PVRV 

API standards are provided as an engineering aid for specification and selection of “normal” and “emergency” pressure and vacuum relief valves for aboveground liquid petroleum storage tanks. Normal venting capacity is obtained without exceeding pressure or vacuum that would cause physical damage or permanent deformation to the tank. The following will help in sizing a pressure/vacuum valve: 

  1. NORMAL RELIEF : the sum of vapor replacement resulting from emptying or filling and thermal in-breathing or out-breathing.
  2. EMERGENCY RELIEF : thermal out-breathing from fire exposure.
  3. ALL TANKS : generally, require the sizing of a normal pressure and vacuum relief valve to be sized and an independent emergency relief valve to be sized separately.
  4. FLOW CURVES : these curves provide pressure and vacuum capacity which is required for sizing.

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Vienne Tan

Mobile: +6019-3328827
Email: wyt@tenergyindustries.com