What is a valve? And why is valve checking important?

What does a valve consist of?

A valve is an application/product that controls the movement of a fluid or gas.It manages the direction and/or controls the flow of a fluid or gas by opening and closing one or more steps.

Valves play a crucial role in most industries that involve pipelines or other applications. Some of the most common sectors that  use industrial valves are the Oil  & Gas Sector, Cryogenic Sector, the Petrochemical Sector, the Naval Sector, the Desalination Sector and some others.

What types of valves exist in the industrial market?

There are 6 different types of valves: Globe valves, gate valves, ball valves, butterfly valves, check valves and plug valves. Each valve has a different design depending on the characteristics of the application and also on the pressure. Therefore, different industries/sectors mean different valves.

What types of valves are worked at Asimer Group?

The extensive experience of the Asimer Group focuses mainly on the following types of valves:

  • Gate valves
  • Globe valves
  • Ball valves
  • Check valve
  • Plug valves
  • Butterfly valves
  • Axial valves

Why is a valve test important?

As the valves are a critical application in many industries, it is important that they work reliably, safety and accurately – that is, they manage  the proper pressure without leaks , every time. There have been cases where these high pressure systems have suffered leaks  (even explosions), which have led to failures in the industrial plants where they are installed. Therefore, it is important to ensure that the system maintains its integrity for security and productivity reasons.

What does a maintenance and pressure test on valves  consist of?

Valve tests are carried out as a maintenance process to assess the condition or health of an operating valve. The following ones, are the functions of a valve tests machine in a high pressure system:

  • Valve leak tests
  • Seat and seal test
  • Seat leak inspection
  • Suitability for fluid and gas testing

Valve tests  are typically done to rectify problems such as mechanical friction, cavitation, plugged flow, erosion, and valve noise, among others.

The benefits of these valve pressure tests are that they are all automated, allowing them to create a record of all previous data. Additional features such as test benches, vacuum tests and customizable equipment are also provided according to requirements.

Why does a valve corrode and how to prevent its corrosion?

As the valves are constantly exposed to fluids (gasses and liquids, many of them toxic and/or abrasive), there is a high probability that the system (set of valves, pipes, connections, etc…) will begin to corrode. Other common problems that occur are that minerals build up to create leaks.

Valve corrosion is commonly considered as damage to the metallic material of the valve under the effect of a chemical or electrochemical environment. Since «corrosion» occurs in the spontaneous reaction between the metal and the surrounding environment, corrosion prevention focuses on how to separate the metal from the surrounding environment or use more synthetic non-metallic materials. Here we are going to list the different ways to prevent valve corrosion:

  • Electrochemical protection
  • Use of non-metallic material
  • Metal surface treatment
  • Choose corrosion-resistant materials according to the corrosive medium
  • Spray coating
  • Add corrosion inhibitors
  • Thermal spray
  • Control corrosive environment
  • Improve processing technology and valve structure

Summarizing, we could say that electrochemical corrosion corrodes different types of metals. It acts between the two metals. Some metals are not resistant to corrosion, but they are capable of producing a very good protective film, that is, a passivation film that can prevent corrosion of the medium.

The most useful methods to prevent valve corrosion:

  •  Create a passivation film on the metal surface.
  •  Use non-metallic materials instead of metallic materials without electrochemical corrosion.

How often is valve pressure check required?

Depending on the pressure the valve is faced with, the ideal scenario would be that the tests were done every two months or every year, according to  the application and the pressure you are working at.