The hydraulic process and procedure of media flow rely heavily on the quality of the valves. A faulty valve can lead to significant damage to a piping system. The failures may lead to catastrophic property damage or worker injuries and death in some cases.
Valve inspection and routine testing are important risk mitigation practices due to their critical role in complex and intricate processes. In this article, we will discuss the types of valves, causes of leaks, the importance of valve testing, etc. today.
You may need to contact oil and gas valve manufacturers if you own a petrochemical industry.
What is a valve?
Controlling the flow of gas or fluid is the job of a valve. Through the opening and closing of various passageways, it controls the direction of flow of a fluid or gas.
Most industries that involve pipelines or other applications use valves on a regular basis. Valves are used in a variety of industries, such as the oil, gas, petrochemical, and marine industries.
Types of valves
- Butterfly Valve
- Ball Valve
- Globe Valve
- Check Valve
- Needle Valve
- Gate Valve
- Pinch Valve
- Plug Valve
- Pressure Relief Valve
How do valve leakages happen?
An unrestrained leak in a valve can occur in two ways: fugitive emissions from the valve going into the atmosphere, and leaks occurring within the piping system while the valve is open.
In addition to damaging the environment, the first can pose a safety risk to people. Quality management and valve testing are important for all of us since valves are the major source of fugitive emissions. You might also require vacuum contactors in case of any electrical hazard posed by valves leakage.
Common causes of valve leakages
Valve leakage can occur for a variety of reasons, including a valve that does not completely close due to dirt, rust, or line debris blocking the valve seat from closing; inadequate actuator travel; and damaged valve seats.
The testing will check for all of these potential problems and other factors that may lead to leaks.
Why is valve testing important?
Because valves are a crucial part of many industrial processes, they must work correctly, directing the right amount of pressure without leakage. In the past, leaks in high-pressure systems have caused explosions if the pressure transfer is inaccurate. The safety and productivity of such high-pressure systems must maintain joint integrity.
As part of valve maintenance, valve testing is carried out to determine whether a valve is operating normally. In a high-pressure system, a valve testing machine performs the following functions:
- Testing for any valve leakages
- Seat leakage inspection
- Seat and seal test
- Suitability for oil and gas testing
Valve testing is generally performed to resolve issues such as mechanical friction, clogged flow, erosion, flashing, cavitation, and noise in valves.
This valve testing machine provides the benefit of automating all the tests, so all previous data can be logged. The equipment also provides rotating test benches, vacuum testing, and customization based on requirements.
International Standards for valve testing
There is an increase in global sourcing, yet domestic manufacturing has decreased, to the point that every component of the valve supply chain needs more testing.
Establishing standards achieves two objectives: it stipulates the criteria that a valve must meet or exceed, and it establishes how the valve will be tested. It also ensures that the valves are operational within the process and that their integrity is maintained. This type of operation depends on reliability and longevity, and testing allows us to make adjustments and repairs when necessary.
In industries, valve inspections are carried out following some international standards. We have listed some of them below-
- API 598: Valve Inspection and Test
- ISO 5208: Industrial Valves, Pressure Testing of Valves
- ISA-S75: Hydrostatic Testing of Control Valves
- ASME B16.34: Valves – Flanged, Threaded, and Welding End
- ASME PTC 25: Pressure Relief Devices
- MSS SP85: Cast Iron Globe and Angle Valves
- FCI 70-2: Control Valve Seat Leakage
- API 527: Seat Tightness of Pressure Relief Valves
- MSS SP61: Hydrostatic Testing of Steel Valves
Important Types of Valve Inspection and Testing
Let’s examine those evaluation measures to gain a better understanding of the types of testing that are used to determine the health and effectiveness of valves in industrial settings.
1. Valve Shell Test
Leaks are checked by partially opening the valve and applying hydrostatic pressure 50% higher than its rated working pressure. The operation is conducted at a specific pressure. Additionally, specific water temperatures apply (41°F to 122°F). There must be no leakage from the valve to pass the test. A valve material made of stainless steel must have a chloride ion content of fewer than 100 parts per million.
2. Valve Seat Leak Test
A valve with its inlet subject to hydrostatic pressure and its body filled with testing fluid is tested at a certain temperature using the valve completely closed.
Leaks are monitored on the valve’s outlet side. When 100 °F is reached, the pressure cannot be lower than 110%. A minute of applied pressure is usually sufficient. The stem and packing of the valve cannot leak during the test. There should be little to no leakage from the disc and seat seal.
3. Pressure Safety Valve Inspection
During this valve inspection, the inlet and outlet piping is observed with the pressure safety valve removed.
A check is made for deposit accumulation, cracking, pitting, corrosion, roughness, or any other damage to the following parts:
- External surface
- Discharge nozzle
- Flanges
- Spring and bellows
Conclusion
We hope this article was helpful in letting you know the importance of valve testing and why it is crucial to invest in a high-quality valve for your industry. So, you must buy from a manufacturer whose products qualify for all the necessary testing procedures. If you require dehydrating agents for highly humid air and gases, you can contact activated alumina desiccant manufacturers.
