BT-Maric constant flow valves type Wafer available in different sizes (DN20-DN400) and in different materials (Stainless Steel, Brass, Gunmetal, UPVC)

How does our constant flow valve type Wafers work?

BT-Maric constant flow valve type Wafers is equipped with one or several flexible rubber control O-rings with an orifice diameter that responds instantly to pressure variations (within a given range).

Control rubbers for BT-Maric constant flow valves type Wafers (Nitrile, Low Pressure, High Pressure, EPDM, Viton etc.)

When the pressure increases the O-ring is pressed down into the conical seat and the orifice of the O-ring decreases in size so that the water flow remains constant at the pre-set nominal flow rate, and vice-versa.
In this way the pre-set nominal flow rate is kept constant at all time regardless of the pressure variations.

BT-Maric constant flow valve type Wafers

BT-Maric Wafers provide a constant, pre-determined, flow rate for water and similar media regardless of the pressure variations. BT-Maric Wafers are designed to be placed between flange mountings for pipe sizes between DN20 up to DN400. They control flow rates up to 13 500 L/min. Wafers are the preferred choice for higher flow rates and larger pipe sizes. There is no need to rotate pipes for disassembly.

Assembling valves Video

Unique Features :

  • Wide range of flow rates available for water and other media up to 13 500 L/min.

  • Simple, compact, reliable and characterized by a long life (up to 20 years).

  • Easy to install between the flange bolts.

  • High accuracy of flow control: With our standard control rubber types PRECISION, we achieve an accuracy level of +/- 10% of the nominal flow rate. PRECISION covers the pressure drop range of 1,4 – 10 bar. (Other pressure drop ranges are available).

  • Available in sizes from DN20 to DN400.
    Complete range of BT-Maric constant flow valves type Wafers available in different sizes (DN20-DN400) and in different materials (Brass, Gunmetal, UPVC, Stainless Steel)
Click to view all features

• Solutions available from 0,4 up to 20 bar.

• Wide variety of materials of material available: brass, stainless steel, gunmetal, U-PVC, POM, PVD-F, Titanium, Duplex, PE …

• 100% mechanical solution: no additional power source needed.

• Self-cleaning, self-regulating.

• Maintenance free: no need for spare parts. Due to the valves unique design and lack of wearing components spare parts are not available.

• The constant flow valves are primarily for water applications and these valves are particularly suitable for use on poor water quality, because the flow controlling element is a rubber material, and flexes under normal operation conditions. This greatly minimizes the risk of blockage and elimi-nates the build-up of scale.

• Pre-set flow rate to avoid adjustment errors or unwanted system changes.

• Customized solutions are available.

Download Data Sheets :

Brass Wafer type valves
Gunmetal Wafer type valves
PVC Wafer type valves
Stainless Steel Wafer type valves

Specifications for BT-Maric Wafer Valve Type

Standard nominal flow rate 0,15 – 8854 L/min.

See all available nominal flow rates


Standard flow rate accuracy: +/- 10% within the pressure drop range of 1,4 – 10 bar.


Standard operating pressure drop range: 1,4 – 10 bar

Solutions for other operating pressure drop ranges

Control rubbers for BT-Maric constant flow valves type Wafers (Nitrile, Low Pressure, High Pressure, Viton, EPDM etc.)


Standard Operating Temperature:
≤ 60°C

Solutions for other operating temperatures


Control rubbers for BT-Maric constant flow valves type Wafers (Nitrile, Low Pressure, High Pressure, EPDM, Viton etc)
Operating Temperatures: up to 200°C (depending on the control rubber type and material of the housing).


BT-Maric cosntant flow valves type Wafers available in different sizes from DN20-DN400Standard size: DN20 up to DN 300 according to ISO 7005 (PN10)

Max Flow rate per Valve body size

Please contact us for customized wafers or wafers according to ISO 7005 (PN16) or other standards such as ANSI etc.


BT-Maric constant flow valves type Wafers available in different materials (brass, gunmetal, UPVC, stainless steel)
Standard materials for valve body: Brass, Gunmetal, U-PVC and Stainless Steel.

Material Options

Other material options: POM, PVD-F, Titanium, Duplex, PE …


Do not hesitate to contact us for any queries. We will be more than happy to provide you with either a standard or customized solution.