Check and bottom valves for safe flow control in the process industry

What is a non-return valve?

A check valve is a self-acting valve that:

• Letting media through in one direction

• Closes automatically when flow is reduced

• Prevents backflow in the system

• Protects pumps and process equipment

Non-return valves are often used in pumping systems and pressurised pipelines where backflow can cause malfunctions or damage.

Different types of check valves

Lyma offers several types of check valves depending on the application and media:

Ball check valve

A robust solution where a ball seals against the seat. Suitable for dirty or particulate media.

Flap check valve

Has a swinging flap that opens at flow and closes at back pressure.
To minimise the pressure drop, the Asahi flap check valve is recommended, which provides virtually free flow when fully open.

Ring check valve

Compact design, often used in tight installations.

Seat check valve

Provides secure sealing and is used where high tightness is essential.

What is a bottom valve?

A bottom valve is fitted at the end of a suction line and prevents the liquid from flowing back when the pump stops.

It is usually equipped with:

• Integrated strainer basket

• Protection against solid particles

• Function to keep the suction line filled

Bottom valves are mainly used in pumping systems to ensure stable starting and prevent dry running.

Connections and dimensions

Check and bottom valves can be supplied with several connection options:

• Wafer (clamping between flanges)

• Flange connection

• Welding connection

• Thread connection

• Glue connection

The dimensional range is DN15-500, which covers most industrial needs.

Check valves for corrosive and aggressive media

Lyma provides check valves in materials adapted for:

• acids and bases

• chemicals

• corrosive liquids

• aggressive process media

Material selection is customised accordingly:

• temperature

• pressure

• chemical resistance

• particle content

We help you choose the right valve for optimal reliability and service life.

Advantages of check and bottom valves

• Automatic function without external manoeuvring

• Protects pumps and systems from backflow

• Reduces the risk of downtime

• Available in several designs and materials

• Adapted for demanding process industries

Need help choosing a non-return valve?

Contact Lyma we will help you design the right check or bottom valve for your application - focusing on safety, flow optimisation and longevity.