Verder VA25 Air-Operated Double Diaphragm Pump
Overview
The Verder VA25 is a compact, high-efficiency air-operated double diaphragm (AODD) pump from the Verderair range, built with a 1 inch liquid connection and a 1/2 inch NPT air connection for medium-duty transfer, container emptying, and basic dosing duties. Available in metallic center-section construction (aluminium or conductive polypropylene) with a wide choice of diaphragm, valve seat, and ball materials including PTFE, Santoprene, Buna-N, Viton, and Hytrel, the Verder VA25 can be matched precisely to the chemical compatibility of the fluid being handled, from mild aqueous solutions to aggressive solvents and abrasive slurries.
Seven Star LLC supplies the Verder VA25 to industrial and process facilities across Oman, Muscat, Sohar, Salalah, and the wider GCC as an authorized partner for genuine Verder and Verderair pumps and spare parts. Every Verder VA25 shipped through Seven Star LLC is factory-sourced with full documentation and backed by local technical support, so maintenance teams in the Sultanate of Oman can select the correct wetted-part configuration and keep dosing and transfer stations running without downtime caused by mismatched materials or unsupported substitutes.
Operating Principle
The Verder VA25 uses two opposing flexible diaphragms connected by a shared shaft, driven by compressed air acting alternately on each diaphragm through a modular air valve. As one diaphragm is pushed forward on its discharge stroke, the shaft pulls the opposite diaphragm backward on its suction stroke, drawing fluid in through a check valve while the first side pushes fluid out through its own check valve; the air valve then reverses automatically once the stroke completes, giving continuous, self-priming pumping action with no rotating seals or packing glands in contact with the pumped fluid.
Because the Verder VA25 is driven entirely by compressed air rather than an electric motor, output flow and pressure are controlled simply by throttling the air supply, and the pump can be run against a closed discharge valve indefinitely without overheating or damage, stalling safely until the valve reopens. This same characteristic makes the Verder VA25 inherently dry-run safe, tolerant of cavitation, and suitable for installation in areas where running electrical power to a motor-driven pump would add cost or complexity.
Engineering Design
The Verder VA25 delivers a maximum flow of up to 49.9 GPM (189 L/min) and a maximum discharge and air input pressure of 124.7 PSI (8.6 bar), with a maximum solids particle size of 0.13 inch, dry suction lift of up to 16 feet, and wet suction lift of up to 28.9 feet, figures that cover the great majority of drum, IBC, and sump transfer duties encountered on Omani industrial sites. Maximum handled viscosity reaches 10,000 cPs and maximum fluid temperature 275 degF, depending on the diaphragm and seat elastomer selected, giving flexibility across chemical dosing, wastewater, and general process transfer applications.
Wetted parts on the metallic Verder VA25 are offered in aluminium or stainless steel, with the center section available in polypropylene, aluminium, or conductive polypropylene for installations that require static-dissipative construction. ATEX-certified variants are available for use in classified hazardous areas, using pneumatic actuation at the pump head rather than electrical power, which suits refineries, tank farms, and chemical storage areas across the GCC where ignition sources must be tightly controlled. The modular air valve design allows field-level rebuilds without special tooling, minimizing spare-parts holding and downtime.
Key Features
- 1 inch liquid connection with 1/2 inch NPT air connection, compact footprint
- Maximum flow up to 49.9 GPM (189 L/min) at up to 124.7 PSI (8.6 bar)
- Inherently dry-run safe with no mechanical seals or packing glands
- Self-priming with wet suction lift up to 28.9 feet
- Handles viscosities up to 10,000 cPs and solids up to 0.13 inch
- Metallic construction in aluminium or stainless steel wetted parts
- Wide elastomer choice: PTFE, Santoprene, Buna-N, Viton, Hytrel
- ATEX-certified variants available for classified hazardous areas
Air Consumption, Cycle Rate, and Noise
Sizing the compressed-air supply correctly is the single most important factor in getting predictable performance from the Verder VA25. Each pumping cycle displaces approximately 0.17 gal (0.64 litres) of fluid, and the pump will run to a maximum of 280 cycles per minute, although Verder recommends a continuous duty rate of roughly 93 to 140 cycles per minute to maximise diaphragm and air-valve service life. Air consumption is approximately 25 scfm when the pump is delivering 20 GPM at 70 PSI inlet pressure, rising to a maximum of around 67 scfm at full flow, so a plant air header serving several units must be dimensioned against the combined worst-case demand rather than the nominal figure.
Because an AODD pump exhausts its drive air to atmosphere on every stroke, noise matters in enclosed pump rooms and dosing skids. The Verder VA25 produces a sound power level of about 78 dBA at 70 PSI and 50 cycles per minute, rising to roughly 90 dBA at 100 PSI and full flow, with sound pressure levels of about 84 dBA and 96 dBA respectively. Piping the 3/4 inch NPT(f) air exhaust away from the operator position, or running at the lower end of the recommended cycle band, keeps the working environment within normal hearing-protection thresholds. Unit weight ranges from roughly 18 lb for the lightest build to around 41.4 lb for stainless steel wetted parts on an aluminium centre section.
Industrial Applications
Across Oman’s industrial base, the Verder VA25 is applied to chemical dosing and transfer, wastewater and sludge handling, drum and IBC emptying, mining slurry transfer, and general fluid movement in food, pharmaceutical, and manufacturing plants wherever self-priming, low-shear, dry-run-safe operation is needed. Its ability to run indefinitely against a closed valve makes the Verder VA25 a practical choice for batch dosing stations and tank-changeover duties where flow may stop and start repeatedly through a shift.
As an authorized partner of Verder, Seven Star LLC positions the Verder VA25 for chemical processing, wastewater treatment, mining, and general industrial customers throughout Muscat, Sohar, Salalah, and the broader GCC, supplying genuine pumps alongside material-selection guidance so that new installations and pump replacements use correctly specified wetted parts rather than unsupported substitutes.
Installation, Grounding, and Maintenance
Correct installation of the Verder VA25 begins with the compressed-air train. Verder specifies an air filter and regulator assembly upstream of the pump to remove moisture and contaminants and to set the drive pressure, together with a bleed-type master air valve fitted downstream of the regulator so that trapped air can be safely relieved before any maintenance work is carried out. Fluid connections are available as 1 inch NPT or BSPT threaded ports or as 1 inch ANSI/DIN flanges, which simplifies tying the pump into existing pipework without adapters. Grounding is mandatory: a 12 AWG minimum conductor bonded to the pump ground screw, torqued to no more than 15 in-lb. Static-dissipative build options and correctly bonded suction and discharge hoses matter particularly where the Verder VA25 transfers flammable solvents.
Routine maintenance is straightforward and can be carried out by site fitters without specialist tooling. The pump should be flushed before any pumped product has a chance to dry inside the wetted path, and fastener torques should be rechecked roughly every two months: fluid cover and manifold fasteners to 90 in-lb (10.2 N·m), plastic air-valve fasteners to 55 in-lb (6.2 N·m), and metal air-valve fasteners to 80 in-lb (9.0 N·m). Fluid temperature limits are set by the elastomer rather than the pump body, so a Buna-N diaphragm on a metallic pump is restricted to roughly 10°F to 180°F while PTFE extends the range considerably. ATEX-certified units carry an Ex h IIC Group II Category 2 GD marking, and the applicable certificate should be checked against the site area classification before installation.
Technical Specifications
| Model | VA25 (HE) Metallic |
|---|---|
| Manufacturer | Verder (Verderair) |
| Pump Type | Air-operated double diaphragm (AODD) |
| Liquid Connection | 1 inch BSP/NPT |
| Air Connection | 1/2 inch NPT |
| Max. Flow | 49.9 GPM (189 L/min) |
| Max. Discharge / Air Pressure | 124.7 PSI (8.6 bar) |
| Max. Suction Lift (dry / wet) | 16.1 ft / 28.9 ft |
| Max. Solids Particle Size | 0.13 inch |
| Max. Viscosity | 10,000 cPs |
| Wetted Materials | Aluminium, Stainless Steel |
| Certifications | ATEX (available) |
Get a Quote
Seven Star LLC is an authorized Verder partner supplying the Verder VA25 and the full Verderair diaphragm pump range across Oman, Muscat, Sohar, Salalah, and the GCC. Contact Seven Star LLC today for pricing, stock availability, and material-selection support on your Verder VA25 pump requirement.
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