Explain the working principle of external gear pump with sketch.

-

 The basic principle of this type of pump is that a pair of gears being driven by an external means. The gear motion generates suction at inlet by creating a partial vacuum, which causes fluid to be drawn into the pump housing. The fluid is drawn through the pump and is displaced as the teeth mesh on the outlet side.



External gear pump have two mating gear that are turned in a closely fitted casting.Each gear is mounted on a shaft which is supported on bearing in the end covers. In this drive shaft is coupled to the prime mover. Two ports, inlet and outlet are provided directly on the opposite side of the mesh point of the gears. The larger and straight ports are preferred for better performance. The driving shaft is usually connected to the upper gear of the pump. The rotation of the driver gear causes the follower gear to turn.

When the pump starts rotating, the rotation of the gear forces air out of the casing and into the discharge pipe. This removal of air from the pump casing produces a partial vacuum on the suction side of the pump. Fluid from an external reservoir is forced by the atmospheric pressure into the pump inlet.Here the fluid is trapped between the teeth of the upper and lower gear and the pump casing. Continuous rotation of the gear forces the fluid out of the pump discharge.

A vacuum is formed in the cavity between the teeth as they un-mesh, causing more fluid to be drawn into the pump. Pressure rise in the pump is produced by the squeezing action of the fluid as it is expelled from between the meshing gear teeth and the casing.

Comments

Post a Comment

Popular posts from this blog

What are the types of the gear pumps? With neat sketch discuss construction working of any type of gear pump.

-
Image
 There are four types of gear pump External Gear Pump Internal Gear Pump Screw Pump Lobe Pump The basic principle of external gear pump is that a pair of gears being driven by an external means. The gear motion generates suction at inlet by creating a partial vacuum which causes fluid to be drawn into the pump housing. The fluid is drawn through the pump and is displaced as the teeth mesh on the outlet side. Construction: External gear pump have two mating gear that are turned in a closely fitted casing. Each gear is mounted on a shaft which is supported on bearing in the end covers. In this drive shaft is coupled to the prime mover. Two ports inlet and outlet are provided directly on the opposite side of the mesh point of the gears. The larger and straight ports are preferred for better performance. The driving shaft is usually connected to the upper gear of the pump. The rotation of the driver gear cause the follower gear to turn. Operation: When the pump starts rotating the rotation
Read more

With neat sketch explain the working of a pressure compensated flow control valve and pressure unloading valve.

-
Image
  Oil from the pump flows through the flow central valve and the flow is restricted. The approach to the adjustable restrictor is also through the pressure compensator spool. There is enough passage and space around the compensator for the oil to reach the restrictor. Let us say the pump flow is 221/min and the restrictor is adjusted to allow 101/min. There is a balance flow of 121/min which will be building up pressure in the pipe line P. The load pressure from port A of the cylinder is felt on the outlet of the flow control valve. If the spring rating is 1 bar and the load pressure at port A is 50 bar then the pressure felt on the left-hand side of the pressure compensator is 51-bar. The pressure on the right side of the compensator slowly builds-up. When this pressure reaches a pressure level just above 51-bar, the pressure compensator moves towards the left compressing the spring. In moving the passage to the restrictor is narrowed by the landing of the pressure compensator. This i
Read more

State the sequence of events in system of design cycle ( General procedure of machine design).

-
  General Procedure in Machine Design: In designing a machine component there is no rigid rule. The problem may be attempted in several ways. However the general procedure to solve a design problem is as follows:  Recognition of need: First of all make a complete statement of the problem indicating the need aim or purpose for which the machine is to be designed.                                                                     Synthesis (Mechanisms): Select the possible mechanism or group of mechanisms which will give the desired motion.                                                                                                                               Analysis of forces: Find the forces acting on each member of the machine and the energy transmitted by each member.                                                                                                                          Material selection: Select the material best suited for each member of the machine.       
Read more