Self-priming horizontal screw pump for non lubricating liquids

 

The Houttuin double entry twin geared screw pumps series 200/300 are rotating self priming positive displacement pumps. The two screwshafts which are working together are rotating in the pump casing with a replacable liner. Because of the special screw profiles the liquid is being pumped with minor backflow. In addition to the foregoing plus the fact of the exact design and manufacturing of the screw profile the pump has very good suction qualities (NPSH) and a high efficiency.

 

Design

According to the specifications of the enduser complete with all details of the liquid to be pumped e.g. temperature, viscosity, pressure, capacity etc. the exact dimensions and profile of the screwshafts are calculated on our advanced CAD -system.

This means the optimum proportion between diameter, length and pitch of the screwshafts combined with the shortest bearing span; this results in the best outlines of the spindles having minimum deflection. Also the fact that the screwshafts are machined out of one solid piece of material contributes to the strength of the shafts.

 

The screwshafts are allocated on both sides in

either ball or roller bearings and axially fixed at one end. Due to the double suction design the hydraulic axial forces are eliminated, therefore the axial bearings are only for fixing the position of the screwshafts. The torque from the driving spindle to the

driven shaft is being transferred by timing gears which are located in a separate housing and are oilsplash lubricated.

The rigid design of the screwshafts and their exact location in the casing of the pump due to the bearings complete with the setting of the timing gears results in free running of the rotors, so no rotor to rotor and no rotor to casing contact. No metallic contact means no wear. Even dry running is possible for a short period. All parts which are in contact with the liquid being pumped are made out of materials which are most suitable for the duty. The pump casing is made either of cast or fabricated steel and can be adapted to all the requirements of the customer. All quality requirements such as ASME , NACE etc. can be fulfilled.

 

The pump is equipped with a replacable liner which gives an advantage in the event of extensive wear due to abrasive duties.

The pump is built according international standards such as API 676 and adapts API 682 for mechanical seal arrangements.

The pump is suitable for direct drive by an electric or hydraulic motor, diesel engine or turbine.

 

 

Performance data  

Capacity

Viscosity range

Temperature of pumped liquid

Difference pressure

Q

V

t

dp

up to 2500 m3/h

0,6 to 100.000 cSt 

up to 400 ºC 

up to 80 bar

 

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Houttuin BV
Last modified:  07/10/2009