Grundfos DMX 226-B Mechanical Diaphragm Dosing Pump with External Motor

The Grundfos DMX 226-B Mechanical Diaphragm Dosing Pump is a high-capacity, industrial-grade dosing solution engineered for applications requiring reliable, continuous chemical injection at higher flow rates without electronic control systems. Built on the proven DMX mechanical platform, the DMX 226-B delivers robust performance, long service life, and straightforward operation in demanding environments.

The pump uses a mechanically driven diaphragm, coupled via a precision gear-eccenter-tappet system to a high-efficiency AC motor. Dosing output is adjusted manually by varying the stroke length using a clearly graduated adjustment knob, providing stable and repeatable dosing with a typical adjustment ratio of 1:10.

The liquid end is constructed with a PVC dosing head, PTFE-coated diaphragm, and ceramic ball valves, ensuring excellent resistance to commonly used water treatment and industrial chemicals. The rugged aluminium pump housing and IP65 motor protection make the DMX 226-B well suited to harsh plant environments where reliability and ease of maintenance are critical.

Available in a wide range of flow and pressure combinations, and with both single-phase and three-phase motor options, the DMX 226-B is ideal for water treatment plants, industrial process dosing, and OEM skid-mounted systems requiring a powerful mechanical dosing pump.

VARIANTS

Single-Phase – 1 × 230 V, 50 Hz

• DMX 132-10 – 132 LPH @ 10 bar — Part No. 99206048
• DMX 199-8 – 199 LPH @ 8 bar — Part No. 99206050
• DMX 280-8 – 280 LPH @ 8 bar — Part No. 99206052
• DMX 321-6 – 321 LPH @ 6 bar — Part No. 99206064

Three-Phase – 3 × 230/400 V, 50 Hz

• DMX 132-10 – 132 LPH @ 10 bar — Part No. 99206033
• DMX 199-8 – 199 LPH @ 8 bar — Part No. 99206035
• DMX 280-8 – 280 LPH @ 8 bar — Part No. 99206037
• DMX 321-6 – 321 LPH @ 6 bar — Part No. 99206039
• DMX 460-6 – 460 LPH @ 6 bar — Part No. 99206042
• DMX 525-3 – 525 LPH @ 3 bar — Part No. 99206044
• DMX 765-3 – 765 LPH @ 3 bar — Part No. 99206046

APPLICATIONS

• Water and wastewater treatment chemical dosing
• High-flow industrial process dosing
• pH correction and chemical conditioning
• Cooling tower and boiler water treatment
• OEM dosing skids and packaged systems
• Applications requiring constant, fixed-rate dosing
• Industrial environments where electronics are not required

FEATURES

• Mechanical diaphragm dosing pump with external AC motor
• Manual stroke length adjustment for fixed-rate dosing
• Precision gear-eccenter-tappet drive system
• PVC dosing head suitable for common treatment chemicals
• PTFE-coated diaphragm for long service life
• Ceramic ball valves for accurate, repeatable dosing
• Aluminium pump housing for industrial durability
• Simple design with low maintenance requirements
• IP65 motor enclosure
• Wide range of flow and pressure options
• Available in single-phase and three-phase configurations

SPECIFICATIONS

Performance

• Maximum flow: 132–765 LPH (variant dependent)
• Maximum pressure: Up to 10 bar
• Stroke adjustment ratio: 1:10
• Dosing accuracy: ±1.5% (FS)
• Linearity: ±4% (FS)
• Maximum viscosity: 400 mPas

Hydraulic

• Liquid temperature range: 0 to 40 °C
• Maximum suction lift: Up to 3 m
• Maximum permissible inlet pressure: 0 bar

Materials

• Pump housing: Aluminium
• Dosing head: PVC
• Diaphragm: PTFE-coated
• Valve balls: Ceramic (Al₂O₃)
• Valve seat: PTFE composite
• Valve gasket: EPDM

Electrical

• Supply voltage:
  • 1 × 230 V, 50 Hz
  • 3 × 230/400 V, 50 Hz
• Power input: Approx. 0.4 kW (model dependent)
• Enclosure class: IP65
• Frequency converter: Not prepared for VFD

BENEFITS

• Reliable high-capacity dosing without electronic complexity
• Ideal for continuous, fixed-rate chemical injection
• Excellent chemical resistance for water treatment applications
• Robust mechanical design with long service life
• Easy setup and adjustment via manual stroke control
• Suitable for harsh industrial environments
• Wide model range simplifies pump selection
• Proven Grundfos mechanical dosing technology