Thursday, February 26, 2015

Pump and Compressor



Air Compressor

What is Air Compressor?



When we listen the word compressor, simply we can understand that compressor compresses something. In this problem, compressor compresses the air. An air compressor is a device which converts the mechanical or electrical energy into pressure energy.

How Compressor Works?

When a cold air comes inside the compressor, the compressor compresses the air. So the temperature of the air is increase. The increased temperature air is used in engine for giving the primary heating. These compressors are use in cold region where engine can not start easily. So in that kind of region we need a compressor for heating.

Pump

What is Pump?



Pump is a mechanical device using suction or pressure to raise or move liquids, compress gases, or force air into inflatable objects such as tyres.
Pumps operate by some mechanism (typically reciprocating or rotary), and consume energy to perform mechanical work by moving the fluid. Pumps operate via many energy sources, including manual operation, electricity, engines, or wind power, come in many sizes, from microscopic for use in medical applications to large industrial pumps.
Mechanical pumps serve in a wide range of applications such as pumping water from wells, aquarium filtering, pond filtering and aeration, in the car industry for water-cooling and fuel injection, in the energy industry for pumping oil and natural gas or for operating cooling towers. In the medical industry, pumps are used for biochemical processes in developing and manufacturing medicine, and as artificial replacements for body parts, in particular the artificial heart and penile prosthesis.

Types of Pump

Positive Displacement Pump



A positive displacement pump makes a fluid move by trapping a fixed amount and forcing (displacing) that trapped volume into the discharge pipe.
Some positive displacement pumps use an expanding cavity on the suction side and a decreasing cavity on the discharge side. Liquid flows into the pump as the cavity on the suction side expands and the liquid flows out of the discharge as the cavity collapses. The volume is constant through each cycle of operation.

Positive Displacement Type


·         Rotary-type positive displacement: internal gear, screw, shuttle block, flexible vane or sliding vane, circumferential piston, flexible impeller, helical twisted roots (e.g. the Wendelkolben pump) or liquid ring vacuum pumps
·         Reciprocating-type positive displacement: piston or diaphragm pumps
·         Linear-type positive displacement: rope pumps and chain pumps

Rotary positive Displacement Pump

Positive displacement rotary pumps move fluid using a rotating mechanism that creates a vacuum that captures and draws in the liquid[citation needed].

Advantages: Rotary pumps are very efficient[citation needed] because they naturally remove air from the lines, eliminating the need to bleed the air from the lines manually.

Drawbacks: The nature of the pump demands very close clearances between the rotating pump and the outer edge, making it rotate at a slow, steady speed. If rotary pumps are operated at high speeds, the fluids cause erosion, which eventually causes enlarged clearances that liquid can pass through, which reduces efficiency.

Rotary positive displacement pumps fall into three main types:

·         Gear pumps - a simple type of rotary pump where the liquid is pushed between two gears
·         Screw pumps - the shape of the internals of this pump is usually two screws turning against each other to pump the liquid
·         Rotary vane pumps - similar to scroll compressors, these have a cylindrical rotor encased in a similarly shaped housing. As the rotor orbits, the vanes trap fluid between the rotor and the casing, drawing the fluid through the pump.

Reciprocating positive Displacement Pump

Reciprocating pumps move the fluid using one or more oscillating pistons, plungers, or membranes (diaphragms), while valves restrict fluid motion to the desired direction.
Typical reciprocating pumps are:

·         Plunger pumps - a reciprocating plunger pushes the fluid through one or two open valves, closed by suction on the way back.
·         Diaphragm pumps - similar to plunger pumps, where the plunger pressurizes hydraulic oil which is used to flex a diaphragm in the pumping cylinder. Diaphragm valves are used to pump hazardous and toxic fluids.
·         Piston pumps displacement pumps - usually simple devices for pumping small amounts of liquid or gel manually. The common hand soap dispenser is such a pump.
·         Radial piston pumps