What is a Sanitary Check Valve?
Sanitary check valves are specialized valves designed to pass fluid in one direction, preventing reverse or backflow.
Check valves are relatively simple components widely used throughout processing industries, specifically the sanitary industries, including food processing, beverage processing, and biopharmaceutical manufacturing.
While there are many different types of valves found in the processing industries, we will focus on two, ball check valves** and spring check valves**, which are commonly used in these types of sanitary applications.
These valves are used for various purposes, including:
Evacuating process lines of residual products (in combination with a pressurized air source)
Venting air from the piping system
Clean-in-place (CIP) operations
Reliable, and easy to install.
It requires even less maintenance than ball check valves. Typically, the spring and any O-rings are the only replaceable parts.
It can be mounted either horizontally or vertically.
It is very compact, so it is ideally suited for installation in tight spaces.
WHAT'S COMMON TO ALL TYPES OF CHECK VALVES?
There is a wide range of check valve types, and while each operates somewhat differently, all check valves share a few commonalities.
Compared with other types of valves, check valves are relatively simple and inexpensive to purchase.
These types of valves are mechanically operated and function automatically. Closure pressure is crucial in ensuring a tight seal in fluid systems, preventing backflow and ensuring a positive shutoff. They do not require air, electricity, or manual intervention from an operator to open and close. They also come without valve handles or stems.
When looking at a check valve from the outside, it's hard to tell if the valve is in the open or closed position. Also, operators cannot quickly determine the condition of the valve's internal operating parts from the outside.
Many check valves use a disc or shutter that closes against a seat. These closing mechanisms can stick in the open position, rendering the check valve inoperable.
CHECK VALVES SUITABLE FOR SANITARY PROCESSING APPLICATIONS
CHECK VALVES
Check valves are essential components in sanitary processing applications, ensuring that fluids flow in only one direction and preventing backflow. They are commonly used in industries such as food and beverage, pharmaceuticals, and biotechnology.
The maximum operating pressure of these valves is a critical specification, indicating the highest pressure they can safely handle during operation. Understanding this limit is crucial for ensuring the operational capabilities and safety of the valves in various applications.
Different types of check valves
Ball Check Valve
Ball Check Valves use a moveable ball inside the body of the valve that drops into the fluid flow path in a pipe to stop it.
The valve seat is machined to fit the ball, and the chamber is conically shaped to guide the ball into the proper position to seal and stop a reverse fluid flow (see illustration).
Spring Check Valves
Spring check valves feature a disc, ball, or shutter that is used to stop the flow of liquid in a pipe. These types of check valves are commonly used to assist with the closing pressure in a process line, creating a positive shutoff.
In these types of check valves, a spring pushes the closing mechanism against the valve's seat to stop the flow of fluids. When the fluid pressure on the inlet side of the pipe, above the valve, is higher than the pressure on the outlet side of the valve downstream, the spring compresses, and the fluid stopper opens.
Conversely, when the inlet-side fluid pressure drops, the spring expands, and the valve closes. The pressure differential in the fluid between the inlet and outlet sides of check valves is called the valve's cracking pressure or the pressure required to open the valve.
