Prevents backflow and water hammer
When the pump stops or power is cut, the check valve closes instantly, preventing the fluid from flowing back and the resulting water hammer damage.
Product group · Valve Group
Check Valves and Strainers
Check valves allow fluid to flow in only one direction, preventing backflow when the pump stops or pressure reverses; they protect pumps from water hammer and reverse rotation. Strainers, in turn, hold solid particles in the line on a screen, protecting pumps, valves and measuring instruments from wear and clogging. As Denfor Endüstriyel, we supply spring-loaded, swing-check and wafer-type check valves, and Y-type and basket-type strainers, matched to line diameter and mesh size.
Line diameterDN15 – DN400
Check valve typeSpring-loaded / swing-check / wafer
StrainerY-type / basket-type
Mesh size20 – 100 mesh (depending on application)
Why it matters
What do a check valve and a strainer do?
One protects the pump by preventing backflow, the other holds back solid particles to prevent equipment wear and clogging.
Protects the pump against reverse rotation
Without a check valve, fluid flowing back can turn the pump rotor in reverse; this can damage the pump shaft and mechanical seal.
The strainer protects equipment from wear
Solids in the line, such as sand, rust particles or welding debris, are held on the screen before they can reach the pump, valve or heat exchanger.
Easy-to-clean design
Basket or Y-type strainers can be cleaned by removing the bottom cap, without dismantling the line; this simplifies periodic maintenance.
Types
Sub-types of check valves and strainers
Three types covering two different functions: check valves that prevent backflow, and strainers that hold back solids.
Spring-loaded / swing-check valve
Closes instantly by spring or weight action the moment the fluid stops; the standard check valve type used at pump outlets.
- Fast, automatic closing
- Standard protection at pump outlets
- Reduces water hammer
Wafer-type check valve
A light, economical check valve type without its own flange, clamped between two pipe flanges; preferred on lines with limited space.
- Lightweight construction
- Economical solution
- Tight installation spaces
Y-type / basket-type strainer
Holds solid particles in the line on a screen, protecting pumps, valves and measuring instruments; the basket type offers a higher holding capacity, the Y-type a more compact design.
- Equipment protection
- Easy to clean
- Mesh size matched to need
Selection criteria
What data determines the right check valve / strainer?
Selection can't be made without the first two points. The rest determine the type and equipment.
ParameterWhy it mattersWhat we need from you
Line diameter
Determined by the nominal diameter of the existing pipeline.
DN size
Equipment type
Whether a check valve, a strainer, or both are required.
Check valve / strainer / both
Check valve type
Spring-loaded, swing-check or wafer type, matched to line layout.
Spring-loaded / swing-check / wafer
Strainer type and mesh size
Y-type/basket-type and mesh selection, based on particle size in the fluid.
Y / basket + mesh size
Pressure class
Must match the line's operating pressure.
PN class
Connection size and installation location
Flange size and installation clearance.
DN size + installation clearance
For a quote, having the following is enough
It's fine if you don't have all of it. We'll fill in the gaps together with you.
Create a quote request- Line diameter (DN size)
- Whether a check valve or a strainer is needed
- Check valve type preference (spring-loaded/wafer)
- Strainer mesh size requirement
- Pressure class
- Existing equipment's nameplate data (if a replacement)
FAQ
Questions from the field
The questions we hear most often when quoting check valves and strainers.
Where should a check valve be installed?
It is usually installed at the pump outlet, matched to the flow-direction arrow marked on it; this way, backflow is blocked instantly when the pump stops.
How often should a strainer be cleaned?
It depends on how dirty the fluid is; on newly commissioned lines or lines right after welding, frequent cleaning is recommended in the first weeks, then according to a periodic maintenance schedule.
Should I choose a Y-type or a basket-type strainer?
The Y-type is more compact and suits both horizontal and vertical lines; the basket type has a higher holding capacity and is preferred on lines with heavy fouling.
How is mesh size determined?
It is determined by the maximum particle size the protected equipment (pump, valve, measuring instrument) can tolerate; a finer mesh may require more frequent cleaning.
Do you only serve Istanbul?
No. While our office is on Istanbul's Anatolian side (Ataşehir), we supply and ship across Istanbul's European side, the surrounding provinces and the Marmara region, and Turkey as a whole — covering your equipment end to end, from a single source.
Next step
Let's clarify your requirement together
Share your line diameter and the equipment you want to protect, and let's determine the right check valve or strainer for your line together.
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