HeleShaw Pump (Steering Gear)

Hele Shaw Pump (Steering Gear)

Hele Shaw Pump is named after a Mechanical and Automobile Engineer, Henry Selby Hele-Shaw.

To Remember : Hele Shaw Pump always have Odd number of piston (3,5,7…)

Construction: The variable pump assembly, also known as radial cylinder Hele Shaw pump, consists of a short shaft(one 'short shaft' as show in figure and other at the bottom, which is not shown)

 , which is attached to a cylindrical body that rotates inside the casing. The cylindrical body surrounds a central valve and has ball bearings at the ends(Two ball Bearing in the front side, first one is small another is big, and third is at the other end supports the shaft). The cylindrical ports are connected to each other by means of internal drilled ports, which open in the outer casing from where the oil is supplied and delivered. All the cylinder bodies have pistons inside and are fastened to the slippers by means of gudgeon pin. All these slippers are located inside slots made in the circular floating ring, which can also rotate in any directions because of the bearings mounted in the guide blocks. Two spindles control the movement of the ring and comes out of the casing though the slots provided.

 

 

© Ship Diggers

Working:   Although in many books and article the working of Hele shaw pump is described in Complex manner, but reality is, it working is simple.

Image Credit : Arpit Singh

This pump is connected to an motor for rotation of the shaft at constant speed to which Cylinders is connected, the Floating ring is actuated/Moved by mechanical linkage (Such as Hunting gear) and this movement cause eccentricity of the concentric Floating ring and piston(Cylinders). So, now the Suction and discharge occure as the pump rotate in eccentric state.

The eccentricity of floating ring determine the stroke of piston, floating ring accommodate slippers. As long as concentric state is maintained no suction or discharge occur, as eccentricity occur the suction and discharge starts. Direction of flow depends on the location of the floating ring.

Explanation with respect to picture:

In the Picture we see 5 Cylinders (Odd number), as the Floating Ring is Moved via Mechanical linkage(not shown) toward left side the two piston comes to suction stroke and other two piston in discharge state, while one remain neutral. As the movement is changed the suction become discharge vica-versa.

The pump consist of odd number of radial cylinders which are rotated at constant speed in one direction. The radial cylinder block rotates on a fixed steel centre piece having two opposite one another and in line with the bottom of the rotating cylinders.
In each cylinder is a piston with a gudgeon pin with bronze slipper(not shown in Diagram) on the end. The slipper revolve with cylinder block in grooves machined in the Floating Ring. Movement of the floating ring displaces the cirular path of rotation of the pistons from that of the cylinder block, and produces a pumping action. when the rod is in the mid postion and the centres of rotation of the piston and block coincide, there is no pumping.

 

©Ship Diggers

>> Hele Shaw Pump Animation<<

The article or images Included in the article cannot be reproduced, copied, shared or used in any form without the prior permission of the author and Ship Diggers.