Types Of Reciprocating Member of the Pump

Elements of Mechanical Eng,

1. Gandhinagar Institute of Technology(012) Subject : EME ( 21100 06 ) Active Learning Assignment Branch : Computer : A-3 Prepared by : - Vishvesh jasani (160120107042) Guided By: Prof. Sajan Chourasia Topic Name: Types of Reciprocating member of the Pump

2. Brief flow of presentation Introduction Reciprocating Pump Piston Pump Plunger Pump Bucket Pump

3. Reciprocating Pumps  It is a displacement type of pump.  In this pump, all the amount of liquid sucked in half of cycle of operation is completely displaced to discharge side in the next half of cycle. This pumps have to and fro (backward and forward) motion as distinguished from circular motion of centrifugal and rotary pumps.

4. Classification of reciprocating pump According to type of reciprocating member of pump :- i ) Piston pump :-In this pump piston is a reciprocating member. ii) Plunger pump :- In this pump plunger is a reciprocating member. iii) Bucket pump :-When non return valve is fitted on the piston, the piston is called the Bucket and the pump is called bucket pump.

5. Single Acting Piston Pump  This pump consist of piston or piston or plunger, cylinder, suction pipe with suction valve, deliver pipe with delivery valve and prime mover which drives the pump. 1)FORWARD STROKE (SUCTION STROKE) : the piston moves towards right, crank moves from 0° to 180 °. This creates vacuum in cylinder on the left side of piston causing the suction valve to open. The liquid enters the cylinder and fills it.

6. 2)REVERSE STROKE (DELIVERY STROKE) :  The piston moves towards left, crank moves from 180 ° to 360 ° . This causes increase of pressure in the left side of cylinder. The delivery valve open and the liquid is forced to delivery pipe  The suction and delivery valves are non-return valve, they opens or closes automatically according to pressure difference across theme.

7. Working

8. Double Acting Piston Pump Here, suction and delivery take place simultaneously on opposite sides of piston. 1)FORWARD STROKE : The piston moves toward left side of cylinder, the liquid is sucked from sump through suction valve (SA) .At this moment, the liquid on right side of piston is compressed, the delivery valve (DB) opens and liquid is discharged through this valve. 2) REVERSE STROKE : the piston moves towards left side of cylinder, the liquid is sucked from sump through suction valve SB .At this moment, the liquid on left side of piston is compressed and delivered through valve DA.

9.  The double acting pump give more uniform discharge than single acting pump, as fluid is delivered in both strokes of piston.

10. Plunger Pump A hand operated plunger pump consists of plunger, stuffing box, suction valve, delivery valve and handle. The pump is operated by handle. In order to prevent the leakage of the liquid, the stuffing box, gland and packings are used. Non-return valves are fitted at the suction and delivery pipes preventing back flows.

11. 1) Intake stroke: Plunger moves up, vacuum is created in the cylinder, suction valve opens and liquid enters into cylinder. 2) Discharge stroke: Plunger moves down, suction valve closes and delivery valve opens through which high pressure liquid is delivered to the delivery pipe.

12. Bucket Pump  A bucket pump is single acting vertical reciprocating pump. This pump is used to lift water.  It consists of an open cylinder and a piston with bucket type valve. When the piston moves down, the bucket valve opens and when the piston moves up the valve closes.  A bucket type valve works as a non-return valve.when the pump is put into operation,and the piston moves down for the first time the air below piston mores above it.

13. 1) Intake stroke: Piston moves up the bucket valve remains closed. During this stroke liquid enters into the cylinder through suction valve.  Simultaneously, the liquid above the bucket is forces into delivery pipe through delivery valve. 2) Discharge stroke: Piston moves down, the bucket valve open.  In this stroke neither suction nor delivery of liquid takes place, but the liquid which previously sucked in cylinder moves on upper side of piston.

14. Calculation for Reciprocating pump 1)Discharge(Q) Q=Volume displaced in delivery stroke x No. of cycle per second Q=LA x (N/60) For single acting pump. Q=LA x (2N/60) For double acting pump. L=Length of stroke , A=Cross sectional area of piston. N=speed of pump in rpm

15. 2 ) Power required to drive pump: P=Discharge x Pressure to be developed = Q x ρ gH m Considering the frictional losses and leakage losses, the power required by pump is as, P= ρ gQH m / η P x 1000 kW Power required at motor shaft to drive the pump P= ρ gQH m / η o x 1000 kW

16. 3)Co-efficient of discharge ( C d ): It is the ratio of actual discharge to theoretical discharge. C d = Qa /Q. 4)Slip: It is the measure of return of liquid through the valve or the leakage of liquid from the delivery to the suction end. Slip=Q- Qa Where Q = theoritical discharge Qa = actual discharge