SEKO Spring MS1 Mechanical Diaphragm Dosing Pump 5.5-500 l/h

The SEKO Spring MS1 is a motor-driven mechanical diaphragm dosing pump for flow rates from 5.5 to 500 l/h at up to 16 bar. A spring return mechanism sits in an aluminium housing, driven by a 0.18 to 0.55 kW IP55 motor, and the head can be SS316L, polypropylene, PVC or PVDF. It is the workhorse for larger chemical feed lines where a solenoid pump runs out of stroke volume.

Each model offers three stroke rates (58, 78 and 116 strokes per minute) and three stroke lengths, set manually or by an automatic linear actuator that accepts 4-20 mA.

What a mechanical diaphragm pump brings to bulk dosing

A motor and cam move a diaphragm of 64 to 165 mm diameter, which delivers a steadier, higher-volume stroke than a solenoid drive and is easier to fit with a variable-frequency drive or a stroke-length actuator. The MS1 is therefore used for continuous dosing of hypochlorite, caustic, acid, coagulant and polymer in water and wastewater plants, and for chemical feed on boiler and cooling circuits where several hundred litres an hour are needed. Pressure is up to 10 bar in the standard configuration, and 16 bar for the 064 and 094 diaphragm sizes in the enforced head configuration (customisation code H).

Features from the datasheet

• Flow rates 5.5 to 500 l/h; maximum pressure up to 16 bar (232 psi)
• Motors 0.18 kW three-phase, 0.25 kW single-phase, 0.37 kW three- or single-phase, 0.55 kW single-phase, all IP55
• Heads in SS316L, PP, PVC and PVDF; maximum dosing temperature 40 C for all of them
• Diaphragm diameter 64, 94, 108, 138 or 165 mm
• Stroke rate 58, 78 or 116 strokes/min; stroke length 2, 4 or 6 mm
• Ambient range of use 5 to 40 C
• Optional inverter-driven motors (codes AI and CI) and a version without motor plus adapter kit

Technical specification and performance table

The 10 and 12 bar figures for PP/PVC and PVDF heads on the 064 and 094 models are available with the special reinforced pump head (key code field 9, H) for pressure up to 16 bar.

Reading the ten-field key code

The pump key code has ten fields. The example M S1 B 094 A 51 C4 0 0 0 means: M diaphragm, S1 membrane mechanism, B stroke length 4 mm, 094 diaphragm diameter 94 mm, A stroke rate 58 per minute, 51 head material PP with ceramic diaphragm valve seats set, C4 motor 0.37 kW three-phase 230-400 V, then stroke regulation 0 (manual), customisation 0 and optional 0.

Head codes: 21 SS316 with FPM, 24 SS316 with EPDM, 31 PVC with PTFE diaphragm and ceramic valves, 41 PVDF, 51 PP, 52 PP with SS316 valves. Motor codes: A4 0.18 kW 3-phase, C4 0.37 kW 3-phase, H4 0.25 kW single-phase, L4 0.55 kW single-phase, AI and CI inverter versions, S0 without motor. Stroke regulation L adds the AKTUA linear actuator; customisation H is high pressure; optional 2 means no motor plus adapter kit.

Installation and operation

Mount the pump on a firm base with the suction side flooded where possible, protect the discharge line with a relief valve, and fit a pulsation damper on long lines. The model line shows three fixed stroke rates, so for fine control combine the stroke knob with an inverter motor or the linear actuator and a 4-20 mA signal from a flow meter or analyser. SEKO lists a maximum dosing temperature of 40 C for every head material, so hot liquids need a different pump.

Use in GCC plants

MS1 pumps are typical for hypochlorite and caustic dosing at desalination post-treatment, coagulant dosing at water treatment works, and acid or inhibitor dosing in cooling-water systems at power and petrochemical plants. Strong sun on a metal skid will raise liquid temperature, so shade the head and tank.

Selection and installation notes

A dosing pump is sized from the flow and pressure at the injection point, so confirm the chemical, its concentration and temperature, the head and seal materials, the back pressure and the stroke or speed range before ordering. Fit an injection valve and a suction strainer, keep the suction line short, prime the pump before use, and use a pressure relief valve on the delivery side. Wear the protective equipment named on the chemical safety data sheet when servicing the pump.

Information needed for a quotation

Send the full model code, the quantity, the delivery location in Oman or the GCC, the intended use and any accessories needed, so that the complete package can be quoted together.

Documents and supply information

The manufacturer data sheet is attached to this page and should be read together with the project specification and the site risk assessment before a purchase is confirmed. Ratings, standards and dimensions are quoted as printed on that sheet. Lead time, stock position and certificates available with the shipment are confirmed in the quotation, and we supply to Oman and the wider GCC region for industrial, utility and building services projects.

Accessories and related models

Typical add-ons are the AKTUA linear actuator, suction and discharge valves, relief valve, pulsation damper and level switch. Related SEKO models are the Spring PS1 plunger pump for higher pressures and the Spring MSV for small flows. Browse other dosing pumps in Pumps.

Frequently asked questions

What flow and pressure does the MS1 cover?
5.5 to 500 l/h; up to 10 bar standard and up to 16 bar on the 064 and 094 models with the reinforced head.

Which motors can be fitted?
0.18 kW 3-phase, 0.25 kW 1-phase, 0.37 kW 3- or 1-phase and 0.55 kW 1-phase, IP55, plus inverter versions AI and CI.

How is flow adjusted?
By the stroke length knob, by three stroke rates, or automatically through the AKTUA linear actuator on a 4-20 mA signal.

Which head materials are available?
SS316L, PP, PVC and PVDF, all rated for a maximum dosing temperature of 40 C.

Can it be ordered without a motor?
Yes. Motor code S0 is without motor, and optional 2 adds an adapter kit.

Documents and quotation

SEKO SPRING MS1 enquiries are handled by Seven Star LLC, an independent supplier in Muscat that sources genuine SEKO products. Please include the flow in l/h, discharge pressure, chemical, head material, motor voltage and phase in your message. Please confirm the complete ten-field key code against your duty before ordering. No price is displayed here, and the SEKO Spring MS1 technical data sheet rev 0.7 can be downloaded for checking.