How long after installation will the check valve work properly?

‌After the check valve is installed, if it is installed correctly and the pipeline system is in good condition, it can usually work normally immediately‌. However, to ensure its stability and safety, it is sometimes necessary to wait for some time for observation and testing.

As a key component in the fluid pipeline, the check valve is mainly used to prevent the medium from flowing back and ensure the normal operation of the pipeline system. Its working principle is to rely on the weight of the opening and closing parts (valve disc) and the medium pressure to achieve automatic opening and closing. When the medium flows in from the inlet end, the valve disc is pushed open and the medium can flow; when the medium flows back, the valve disc is closed to prevent the medium from flowing back‌.

When installing the check valve, it is necessary to ensure that the installation process is strictly carried out according to the specifications, including selecting a suitable installation location, correctly connecting the pipeline and the valve, and adjusting the opening and closing status of the valve. If there is negligence or errors in the installation process, the valve may not work properly or even cause a safety accident. Therefore, after the installation is completed, the installation process needs to be carefully checked to ensure that it is correct‌.

In addition, the overall condition of the pipeline system will also affect the use of the check valve. If there are impurities, dirt, or uncleanness in the pipeline system, it may affect the sealing and normal operation of the valve. Therefore, the pipes need to be cleaned before installation to ensure that the pipe system is in good condition.

In some specific cases, such as check valves installed in sewers, to ensure their stability and tightness, it is sometimes necessary to wait for some time (such as 3 hours) before use. However this is not a universal rule, and it depends on the installation situation and the condition of the pipe system.

After the check valve is installed, if it is installed correctly and the pipeline system is in good condition, it can usually work normally immediately‌. However, to ensure its stability and safety, it is sometimes necessary to wait for some time for observation and testing.

As a key component in the fluid pipeline, the check valve is mainly used to prevent the medium from flowing back and ensure the normal operation of the pipeline system. Its working principle is to rely on the weight of the opening and closing parts (valve disc) and the medium pressure to achieve automatic opening and closing. When the medium flows in from the inlet end, the valve disc is pushed open and the medium can flow; when the medium flows back, the valve disc is closed to prevent the medium from flowing back‌.

When installing the check valve, it is necessary to ensure that the installation process is strictly carried out according to the specifications, including selecting a suitable installation location, correctly connecting the pipeline and the valve, and adjusting the opening and closing status of the valve. If there is negligence or errors in the installation process, the valve may not work properly or even cause a safety accident. Therefore, after the installation is completed, the installation process needs to be carefully checked to ensure that it is correct‌.

In addition, the overall condition of the pipeline system will also affect the use of the check valve. If there are impurities, dirt, or uncleanness in the pipeline system, it may affect the sealing and normal operation of the valve. Therefore, the pipes need to be cleaned before installation to ensure that the pipe system is in good condition.

In some specific cases, such as check valves installed in sewers, to ensure their stability and tightness, it is sometimes necessary to wait for some time (such as 3 hours) before use. However this is not a universal rule, and it depends on the installation situation and the condition of the pipe system.

What sizes are available for Check Valves for Oil?

Check valves for oil applications are manufactured in a wide range of sizes to accommodate everything from small-scale lubrication systems to large-diameter crude oil transmission pipelines. The available size is typically designated by the nominal pipe size (NPS) of the system in which it will be installed. The selection of an appropriate size is a fundamental step, as it must match the flow requirements of the system while maintaining functional performance.

For small-bore applications, such as instrument air lines, hydraulic power units, or compressor lubrication systems, check valves are readily available in sizes as small as 1/8 inch or 1/4 inch. These are often of a threaded or socket-weld end configuration. Mid-range sizes, from 2 inches to 12 inches, are common in process plant piping, pump discharge headers, and fuel oil transfer lines. These valves can feature flanged, wafer, or butt-weld ends. For large-scale pipeline transport, such as main crude oil or refined product lines, full-bore check valves are manufactured in sizes extending to 48 inches and beyond. These large valves are almost exclusively of the flanged or weld-end type and are designed with a through-conduit geometry to allow for the passage of pipeline inspection pigs.

It is important to note that the nominal size of the valve must correspond to the pipeline to avoid unnecessary turbulence or pressure loss. However, the internal port size, or bore, is another consideration. While standard check valves have a bore smaller than the pipe diameter (reduced port), full-port check valves are available where pressure drop is a priority, though they often come with a larger overall envelope and higher cost.

How to select Inline Check Valves for Oils & Gases?

Selecting an inline check valve for oil and gas service requires a methodical evaluation of several system parameters to ensure reliable operation and service longevity. The choice is not one-size-fits-all and depends on the specific characteristics of the fluid and the operating conditions.

A primary consideration is the type of media—whether it is oil, gas, or a multiphase flow—and its properties. Viscosity is a key factor for oil; highly viscous oils can slow the disc closure of a swing check valve, potentially to water hammer. For gases, the compressibility and density influence the valve's response. The pressure and temperature ratings of the valve must comfortably exceed the system's normal and peak operating conditions. The required cracking pressure, which is the upstream pressure at which the valve begins to open, must be compatible with the system pressure to ensure the valve opens fully and remains stable, preventing chatter.

The valve type is selected based on the application. Swing check valves are common for horizontal lines with steady flow but are position-sensitive. Dual-plate wafer check valves are compact, lightweight, and fast-closing, making them suitable for many pump discharge applications to prevent reverse flow. Ball check valves and piston check valves are often used for viscous fluids or in applications requiring a higher cracking pressure. Materials of construction must be compatible with the fluid to prevent corrosion; for example, carbon steel may be used for crude oil, while stainless steel is often specified for sour gas or corrosive refined products. Finally, end connections (threaded, flanged, wafer, weld) are chosen to match the existing pipeline and facilitate installation.

Installation steps for Oil Inlet Check Valves

Proper installation is critical for an oil inlet check valve to function as intended. Incorrect installation can leakage, premature failure, or valve damage. The following steps provide a general guideline for a typical installation, though the manufacturer's specific instructions should always take precedence.

• Preparation and Inspection: Before installation, ensure the pipeline is depressurized, drained, and isolated. Carefully unpack the check valve and inspect it for any shipping damage. Verify that the valve type, size, material, and pressure rating match the job specifications. Check inside the valve to ensure it is free of any debris or protective coating that needs to be removed.
• Orientation and Direction: This is the critical step. Many check valves are designed to operate in a specific orientation. A swing check valve must be installed in a horizontal pipeline with the hinge pin horizontal, or in a vertical upward flow line. Piston and ball check valves must be installed with the vertical axis aligned with gravity. The valve body is almost always marked with an arrow indicating the correct flow direction. Confirm this arrow points in the direction of the intended fluid flow.
• Installation and Connection: Position the valve in the line, ensuring it is properly supported to avoid placing stress on the valve body. For flanged valves, insert new gaskets and gradually tighten the bolts in a star pattern to ensure an even seal. For threaded valves, use a suitable sealant tape or paste on the male threads, avoiding application on the two threads to prevent contamination of the valve internals. Do not use excessive torque, as this can damage the valve body or bonnet.
• Post-Installation Check: After the valve is secured and the surrounding piping is reconnected, the system should be gradually pressurized. Check for leaks at the connections. If possible, observe the valve's operation during initial startup to confirm it opens with the flow and closes securely when the flow stops, without excessive water hammer or vibration.