Knowledge bank

What is a non-return valve?

A non-return valve, also known as a "check valve," is a necessary component for managing corrosive flows in the process industry. Its main purpose is to allow the medium to pass in one direction and prevent backflow when the flow slows down. Within check valves, there are two main types: ball check valve and flap check valve.

Asahi's flap check valve - optimal pressure drop

Asahi offers an outstanding solution to minimise pressure drop with its flap check valves. Especially recommended is the Asahi wafer type flap check valve, which covers dimensions DN15-500 and is mounted between flanges. This variant allows virtually free flow with the valve fully open and is an ideal component for handling corrosive flows.

Connection options for ball check valves

Our ball check valves can be customised to your needs and supplied with different connections such as socket weld, butt weld, threaded, glued, flanged or a combination of these. At Lyma, for example, we offer PE butt weld on one end and flange on the other to ensure versatility and ease of installation. Asahi supplies ball check valves from DN15-100, covering various requirements and specifications.

Bottom valves for effective backflow prevention

To effectively counteract the backflow of liquid at suction lines, we recommend the use of bottom valves. These valves are equipped with strainer baskets to prevent the entry of larger particles into the system and ensure smooth operation.

Lyma is your trusted partner for high-performance check valves and related solutions. Contact us to explore our wide range of products and customised options to meet your specific corrosive flow management needs.