Here we will discuss a little about Check Valve and several types of Check Valve.
Check Valve is a device (valve) that is used to regulate fluid (gas, liquid) which can only flow in one direction only and prevent the flow in the reverse direction (backflow).
And this Check Valve does not use handles to regulate flow, but uses gravity and pressure from the fluid flow itself. Because this function can prevent backflow. Check Valve is also often used as a security from an equipment in the piping system.
So in broad outline the way the check valve works is
The check valve actually functions to drain fluid in the same direction with the aim to avoid the occurrence of back flow, or backflow flow.
The way the check valve works can be described as follows, when the fluid flow rate is in accordance with its direction, the flow rate will make a plug or disk open. If there is pressure coming from the opposite direction, the plug or disk will close.
TYPES OF CHECK VALVE
There are 2 types of check valves that are most commonly used in piping systems, namely Swing Check Valve and Lift Check Valve. Swing Check Valve is usually paired with Gate Valve, while Lift Check Valve by several manufacturers is used to replace the Ball Valve function as a Ball Check Valve.
Besides these 2 types, there are still other types of Check Valve that are no less important in the industry, especially in the installation of piping systems.
Then what are the types of check valves?
Here are 6 types of check valves that we often encounter in industry and piping systems:
1. Lift Check Valve
If observed from the configuration, this check valve is very similar to Globe Valve, but what distinguishes it is its rotation, at the Globe Valve the valve rotation or disk can be manipulated, while for Lift Check Valve it cannot be done. The side of the inlet and outlet on the Lift Check Valve is separated by a cone-shaped plug and is located in a holder, generally this material is made of metal.
Its function is when there is a forward flow in the inlet, then the plug will be driven by the pressure of the fluid flow, so that the fluid will go to the outlet side. Whereas if there is back flow, then the plug will close, the greater the pressure generated by the back flow, the more tightly the plug will be on the stand. So fluid backflow will not occur for a long time.
In an industry, Lift Check Valve is used in the process of flowing gas fluid, because the level of leakage in this type of valve is very minimal. In addition, this type of elevator check valve is also often used to prevent condensate return to the steam trap because it can cause adverse effects on steam turbines, for example, cause corrosion.
2. Swing Check Valve
This type of valve has a disk the same size as the diameter of the pipe, the disk or cross section is designed to hang on the top, in contrast to the lift check valve. The principle works the same as an elevator check valve, which is when there is a forward flow, the disk will open and vice versa when there is a backflow. The advantage of swing check valve is that it has low maintenance costs and very low pressure loss. Swing check valve also has a disadvantage, namely the possibility of fluid flow leakage is very possible and less effective to use at low flow due to resistance by cross section.
3. Backwater Check Valve
This type of valve is very common around us, because the backwater valve is used for underground water disposal systems. Maybe some of you use this type of valve in the bathroom of the house. The main function of the backwater valve is to prevent the back flow of water in the drain when there is a flood.
4. Disc Check Valve
Disk Check valve consists of body, spring, spring retainer and disc. The principle works is when there is a flow flow, the disk will be driven by fluid pressure and push the spring so that there is a gap that causes fluid flow from the inlet to the outlet. Conversely if reverse flow occurs, fluid pressure will push the disk so that it closes the fluid flow.
The pressure difference is needed to open and close the valve of this type and this is determined by the type of spring used. In addition to standard spring, there are also several spring options available:
- No spring - Used where the pressure difference in the valve is small.
- Nimonic spring - Used in high temperature applications.
- Heavy duty spring - This increases the opening pressure required. When installed on a boiler water feed line, it can be used to prevent boiler steam from being flooded when they are unpressurised.
5. Swing Type Disk Check Valve
In the use of Swing Check Valve and Lift Check Valve it is limited to large pipes (DN80 or more diameter). so as the solution is to use Disk Check Valve. By using Disk Check Valve can be used tubing with a size that cones on one side so that it can be applied to pipes that are smaller in size.
6. Split Disc Check Valve
Split Disc Check Valve consists of a disk whose center is a shaft that allows the disk to move as if divided in two if pushed from the right direction (foward flow) and closes tightly when pressed from the wrong direction (reverse flow).