Specialty Pumps: Dry Screw Vacuum, Jet Pump, and Micro Solenoid Plunger

When a standard centrifugal will not work: WanGuan dry screw vacuum, stainless flanged jet, and micro solenoid plunger pumps for process, priming, and dosing.

Why these three sit in a specialty folder

Most pump RFQs can be answered with a centrifugal or a screw pump. The remaining jobs need a different physics: deep vacuum without oil in the swept volume, self-priming water lift from a well or a sump, or a few millilitres per stroke inside a machine. WanGuan groups those as specialty pumps so buyers do not search for them under irrigation.

The dry screw vacuum pump, the stainless steel flanged jet pump, and the micro solenoid plunger pump do not substitute for each other. Treat this article as three short specifications stapled together, then open the matching product page for the photo you already saw in the catalog.

Dry screw vacuum pump

A dry screw vacuum pump uses a pair of timed screws to compress gas toward the exhaust without sealing oil in the pumping chamber. That matters for processes that cannot tolerate hydrocarbon backstreaming: drying, solvent recovery discussion, packaging, and some electronics or pharmaceutical utilities. Heat of compression is real; cooling water or air jackets and a correctly sized exhaust silencer are part of a working package.

Give ultimate pressure, pumping speed at the operating pressure, gas composition, and whether condensable vapours are present. A knockout pot or condenser upstream protects the screws. Do not ingest liquid slugs. Materials and coatings depend on the gas; water vapour and light organics are a different conversation from corrosive halides. Ask for an English envelope drawing, noise figure, and recommended inlet screen. For European machinery rooms, discuss ATEX only if the gas is flammable; do not print an ATEX mark on the PO unless the quotation includes it.

Stainless steel flanged jet pump

Jet pumps combine a centrifugal stage with a nozzle and venturi so the unit can lift water from a depth that would starve a plain end-suction pump. The WanGuan stainless flanged jet pump is aimed at clean water, light boosting, and small industrial transfer where corrosion resistance and a flanged pipe match matter. Stainless helps on slightly aggressive water; it is still a water pump, not a chemical pump for strong acids.

State suction lift, discharge pressure, flow, and whether the jet is onboard or a downhole injector. Foot valves leak and are the first thing to check when a jet pump loses prime. NPSH and maximum lift change with water temperature. For a plant utility that must restart after a power cut, confirm the priming volume and whether a vacuum-assisted start is needed instead. Flange drilling should be called out as PN or ASME so the gasket kit in the crate matches the site piping.

Micro solenoid plunger pump

The micro solenoid plunger pump is an OEM component. A coil pulls a plunger and a check arrangement meters a small, repeatable shot of liquid. Typical homes for it are compact dosing, sampling, beverage or chemical metering at very low flow, and laboratory or analyser panels. It is not a process pump for a DN50 line.

Tell WanGuan the liquid, viscosity, required microlitres or millilitres per stroke, maximum back pressure, voltage, and duty cycle. Coil heat and stroke life dominate the design. Elastomers must match the fluid; a photo of a black plastic housing does not define EPDM versus FKM. If the pump sits inside a CE-marked machine, the OEM owns the machinery directive file; WanGuan can support with component drawings and coil data. Mounting orientation and inlet head should follow the drawing, or the ball checks will not seat and the dose will drift.

Buying specialty units without mixing the crate

Keep vacuum, jet, and solenoid lines on separate purchase-order rows even if they ship in one container. Spare parts and manuals do not overlap. For vacuum, plan utilities: cooling, exhaust, and inlet isolation. For jet pumps, plan suction piping and a real priming procedure. For solenoid plungers, plan voltage stability and a filter measured in tens of micrometres, not millimetres.

WanGuan’s export desk will quote from the product names on the site. Attach a short duty paragraph so the team does not assume clean-water irrigation when you actually need 0.1 millibar or 200 microlitres a stroke.