The check valve plays a key role in pipeline development, including switching, splitting, and merging. Generally, In Utmost check valve factory, check valves can be divided into T-type and L-type, each with its own characteristics. The T-type is used for medium splitting, merging, and flow direction switching in the pipeline, while the L-type is used for flow direction switching and can connect two flow channels that are perpendicular to each other under special circumstances. In order to meet the needs of society and production, it is necessary to design the check valve by studying the characteristics of both types.
According to the intended use, American standard check valves can have a fully metallic valve disc or a valve disc with embedded rubber pads or rubber rings. Carbon steel check valves are used as shut-off valves for boiler feedwater and steam, and they have the functions of lifting type check valves, globe valves or angle valves. High-temperature check valves are a type of automatic valve that mainly prevents medium backflow and releases from the container.
In special situations, users not only need to use L-type check valves to switch flow directions, but also hope to use L-type check valves to cut off three pipelines at the same time. Since ordinary L-type check valves do not have this function, users need to install globe valves on three pipelines to achieve this function. This not only increases the cost of the pipeline system, but also makes the system more complex and difficult to operate. Therefore, a new design of the L-type check valve has been innovatively designed with a three-seat structure, as well as a four-seat structure. By adopting a large ball design, the valve not only has the flow direction switching function of an ordinary L-type check valve, but also has the function of simultaneously sealing and cutting off three channels. Thus, through the design of the check valve, its special needs can be met, achieving better production.
The main function of the check valve is to prevent medium backflow, prevent pump and motor reversal, and prevent the release of container media. The check valve can also be used to supply the auxiliary system with pressure that may rise above the system pressure. Check valves can be mainly divided into rotating check valves (rotating based on gravity) and lifting check valves (moving along an axis).
In oilfield surface engineering, commonly used check valves include lifting, rotating, butterfly, and diaphragm valves, which have different valve disc structures and opening and closing methods, making them suitable for different working conditions. Generally, during the initial design phase, process design personnel evaluate the type of check valve required based on the minimum impact pressure or the closing speed required for non-collision closure under specific working conditions. While this method is not very precise, it generally applies to most situations.
Based on this, check valve selection generally adheres to the following principles:
The nominal pressure of the check valve must match the required production pressure in the actual project;
The check valve is not easily corroded by the fluid medium of the affiliated pipeline system;
The friction loss of the check valve when fully open must meet the process design requirements, and the opening and closing components should be in the fully open state during normal production;
The water hammer impact force generated by the check valve must not exceed the threshold strength of the equipment or pipeline system;
The bending strength and fatigue strength of check valve components should meet production operation requirements;
The selected check valve should be economical, small in size, and light in weight while meeting design and production requirements, making it easy to transport and maintain;
Different structured check valves are suitable for pipes of different sizes and pressure conditions, and the selection of a check valve has certain reference significance.