Ship Three Spindle Screw Pump

Ship Three Spindle Screw Pump

The three spindle screw pumps consist of general design type 3G, marine usage pump 3GC and three screw pumps of special design.

The three – spindle screw pump is a positive displacement rotary pump. Inside the pump casing, as the flanks of teeth of drive screw and idler screws are engaged and the screws are also matched with the three inset holes, several sealed moving chambers are thereby formed in – between the pump inlet and outlet end. These closed chambers will take the medium inside to move from the inlet end axially and let fluid be pressurized progressively, to have a continuous, constant, axial flow of pressured liquid.

The three – spindle screw pumps are suitable for pumping various kinds of non – corrosive oil without contents of solid grains and liquids similar to lubricating oils. The viscosity of mediums to be conveyed range from 1.2 to 100°E (3.0 to 760 cst), liquid with a higher viscosity could also be pumped after heating up (lowering down the viscosity). The flow range is 0.2 – 590m³/h, and the maximum working pressure is 100 bar, the highest temperature is 150°C.

1. Simple in construction

The pump has quite a few construction forms. General for small flow range 0.2 – 6.5m³/h, pump casing ang insert is made in one part. Mechanical seal is used as the pump shaft seal.

2. Long service life

The main drive screw of the three – spindle screw pump is driven by the electric motor, with no mechanical contact between the main and from screws, while the driven screws are driven by the liquid pressure to make the from – screw axis line self – rotate. There is no mechanical contact between the main and from screws and between the screws and the liner. Each has an oil film protection, so the mechanical friction is small, and the service life is long.

3. Stable operation, low noise

The liquid in the pump moves axially at a uniform speed. The pressure fluctuation is small, the flow is stable, and the noise is low. Due to small inertia during rotation, the starting torque and vibration are small.

4. High suction capability

To ensure the safety of the motor, electric motor and piping system, medium – and high – flow pumps are equipped with safety valves. When the pressure exceeds the set pressure of the safety valve, high – pressure oil will flow back to the suction port.

5. Installation forms

Pumps of middle and big flow range have a separate insert to be fixed inside the pump casing. Big pumps are mostly of a double – suction design for horizontal installation. For different mediums to be pumped, mechanical seals or packing seals could be supplied. For marine application pumps, installation forms could be horizontal and vertical, with marine AC and DC drivers. Long life time: As the drive screw is driven by motor and there is no mechanical contact between the drive screw and the idler screw, screws set and insert an oil film is formed, so the mechanical friction is minimized and a longer life is ensured.

6. Medium to be pumped

The medium to be pumped is in a manner of constant axial flow movement, so the pressure pulsation is almost eliminated, meanwhile the noise is lowered; and as the moving parts have a very little inertia, the starting torque and vibration is very little.

7. Safety valve

In order to ensure the safe working of pump, motor, piping system, pumps for a capacity higher than middle flow range are all equipped with safety valves. When working pressure is exceeding the setting pressure of valves, pressed oil will circulate back to suction chamber.

Structure Diagram Components

1. Pump casing
2. Pump insert
3. Suction cover
4. Lower cover
5. Upper cover
6. Sealing cover of seal
7. Relief valves

Material Combination Code

Specifications Table (Partial)

Attention please: The description may be different with the product, please contact us for quotation.
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