1. A cylinder with a piston 5. suction pipe
2. piston rod 6. delivery pipe
3. connecting rod 7. suction valve
4. crank 8. delivery valve
Working of a single-acting reciprocating pump
Single acting reciprocating pump:- A single acting reciprocating pump, which consists of a piston which moves forwards and backwards in a close fitting cylinder. The movement of the piston is obtained by connecting the piston rod to crank by means of a connecting rod. The crank is rotated by means of an electric motor. Suction and delivery pipes with suction valve and delivery valve are connected to the cylinder. The suction and delivery valves are one way valves or non-return valves, which allow the water to flow in one direction only. Suction valve allows water from suction pipe to the cylinder which delivery valve allows water from cylinder to delivery pipe.
The rotation of the crank brings about an outward and inward movement of the piston ‘P’ in the cylinder ‘C’. During the suctio
Hydrodynamic Lubrication :- In hydrodynamic lubrication hydro means (liquid) and dynamic means (relative motion) it is the combination of both liquid and relative motion to reduce the friction. In hydrodynamic lubricated bearings, a thick film of lubricant is formed between the journal and the bearing. According to Reynolds their are some essential factors for the formation of a thick film of oil in hydrodynamic lubrication. They are
- A continuous supply of oil is required.
- A relative motion between the two surfaces in a direction approximately tangential to the surface.
- The ability of one of the surfaces to take up a small inclination to the other surface in the direction of the relative motion.
- The line of action of resultant oil pressure must coincide with the line of action of the external load between the surface.
These factors are essential for the formation of thick film between journal and the bearing. In hydrodynamic lubricated bearing the bearing is supplied with sufficient lubricant, a pressure is build up in the clearance space when the journal is rotating about an axis that is eccentric with the bearing axis. The load can be supported by this fluid pressure without any actual contact between the journal and bearing.
The load carrying ability of a hydrodynamic bearing arises simply because a viscous fluid resists being pushed around.Under the proper conditions, this resistance to motion will develop a pressure distribution in the lubrication film that can support a useful load.
The load supporting in hydrodynamic bearings arises from either
- The flow of a viscous fluid in a converging channel(known as wedge film lubrication).
- The resistance of a viscous fluid to begin squeezed out from between approaching surfaces surfaces (know as squeeze film lubrication)
n stroke the piston is moving towards right in the cylinder, this movement of piston causes vacuum in the cylinder. The pressure of the atmosphere acting on the sump water surface forces the water up in the suction pipe ‘S’. The forced water opens the suction valve V1 and the water enters the cylinder.The piston from its extreme right position starts moving towards left in the cylinder.The movement of the piston towards left increases the pressure of the liquid inside the cylinder more than atmospheric pressure. Hence suction valve closes and delivery valve V2 opens. The liquid is forced into the delivery pipe and is raised to a required height.
Discharge through a single acting reciprocating pump.
Working of a Double-acting reciprocating pump.
Discharge through a double-acting reciprocating pump.
S2= Suction valve (closed)
