Présentation au sujet: "Pumps APPLICATIONS, COMPONENTS, TYPES, WORKING,. What are pumps? A pump is a device that moves fluid i.e. liquids or some time slurries by mechanical."— Transcription de la présentation:
What are pumps? A pump is a device that moves fluid i.e. liquids or some time slurries by mechanical action. Pumps can be classified in to three major groups according to the method they use to move the fluid i.e. direct lift, displacement and gravity pumps.
Applications or uses Pumps are used in almost every home as a domestic water suction device for a daily life use.
Industrial applications Building Services - pressure boosting, heating installations, fire protection sprinkler systems, drainage, air conditioning Industry and Water engineering - boiler feed applications, water supply (municipal, industrial), wastewater management, irrigation, sprinkling, drainage and flood protection The Chemical and Process Industries - paints, chemicals, hydrocarbons, pharmaceuticals, cellulose, petro-chemicals, sugar refining, food and beverage production
What Is an industrial pump? There are dozens of different industrial applications a several types of industrial pump designs to fit the requirements. Centrifugal pumps are used often in industrial applications. These pumps use a rotating impeller to accelerate a fluid and increase its pressure. There are dozens of industrial centrifugal pumps including slurry pumps, chopper pumps, sewage pumps, vertical turbine pumps, axial flow pumps and more. In addition, rotary and reciprocating positive displacement pumps are often used in industrial applications to move fluids at steady flow rates with high pressure. Specifically, screw pumps, progressive cavity pumps, lobe pumps, gear pumps, diaphragm pumps, and peristaltic pumps are considered industrial PD pumps.
Components Pump is made of two major components 1) motor The power source of the pump which drives the shaft. AC motors and DC motors are the most common power sources for pumps, but internal combustion engines (ICEs), hydraulic power, and steam power are other possibilities. 2) impeller A rotating disk with a set of vanes coupled to a shaft. When the impeller rotates, it imparts energy to the fluid to induce flow. Flow characteristics of the pump vary widely based on the impeller design.
Pumps are classified in two types 1) Negative displacement pump/centrifugal 2) positive displacement pump Negative displacement pumps or centrifugal: A pump that uses an impeller to move water or other fluids. It produce a head and a flow by increasing the velocity of the liquid through the machine with the help of a rotating vane impeller.
Types of negative displacement pump Axial Propeller: An axial propeller is a common type of pump that essentially consists of a propeller (an axial impeller) in a pipe. The propeller can be driven directly by a sealed motor in the pipe or by electric motor or petrol/diesel engines. Fluid particles do not change their radial locations since the change in radius at the entry and the exit of the pump is very small. Hence the name "axial" pump.
Mixed Flow Pump: The Pump which moves fluid by both radial acceleration and lift and exits the impeller somewhere between 0 and 90 degrees from the axial direction. As a consequence mixed-flow pumps operate at higher pressures than axial-flow pumps.
Positive Displacement Pumps: These positive displacement pumps have an expanding cavity on the suction side and a decreasing cavity on the discharge side. The positive displacement pump operates by alternating of filling a cavity and then displacing a given volume of liquid. The positive displacement pump delivers a constant volume of liquid for each cycle against varying discharge pressure or head.
Types of positive displacement pump Reciprocating pumps: It moves fluid by reciprocating motion of piston. It is often used where a relatively small quantity of liquid is to be handled and where delivery pressure is quite large. In reciprocating pumps, the chamber in which the liquid is trapped, is a stationary cylinder that contains the piston
Positive VS Negative Displacement Pump Flow Rate and Pressure Head: The Centrifugal Pump has varying flow depending on the system pressure or head The Positive Displacement Pump has more or less a constant flow regardless of the system pressure or head. Positive Displacement pumps generally gives more pressure than Centrifugal Pump's. Capacity and Viscosity: In the Centrifugal Pump the flow is reduced when the viscosity is increased In the Positive Displacement Pump the flow is increased when viscosity is increased
Mechanical efficiency Changing the system pressure or head has little or no effect on the flow rate in the Positive Displacement Pump Changing the system pressure or head has a dramatic effect on the flow rate in the Centrifugal Pump
Principle of Operations: Centrifugal Pump: The impeller of such a pump is magnetically coupled with the motor, across a separation wall which is resistant to the fluid pumped. The motor drives a rotor carrying one or several pairs of permanent magnets, and these drag around a second pair of permanent magnets attached to the pump impeller. Positive Displacement Pump: The fluid moved by the pump in one cycle (one suction stroke and one discharge stroke) as the piston moves from its farthest left position to its farthest right position and then to farthest left position.
Advantages And Disadvantages: Advantage of Centrifugal Pumps: As there is no drive seal so there is no leakage in pump. There are very less frictional losses. There in almost no noise. Centrifugal pump have minimum wear with respect to others. There is a gap between pump chamber and motor, so there is no heat transfer between them. Because of the gap between pump chamber and motor, water cannot enter into motor
Disadvantage of Centrifugal Pump: Because of the magnetic resistance there is some energy losses. Unexpected heavy load may cause the coupling to slip. ferrous particles in liquid are problematic when you are using magnetic drive. This is because particle collect at impeller and cause the stoppage of pump after some time.
Advantages of Positive Displacement Pump: In general, positive displacement pumps are ideal for applications where a constant flow is needed. They create medium to high pressure and are often an excellent way to pump oils and other viscous fluids. Positive displacement pumps are also extremely useful for applications requiring a combination of low flow and high pressure. For example, to move fluids containing suspended or fragile solids.
Disadvantages of Positive Displacement Pump: Principally a source of pressure fluctuations, although there are some that produce far less fluctuations than others. In general more gland problems. Dynamic problems with check valves when applicable In general higher maintenance costs. Need for safety relieve valve to protect the piping against exceeding the design pressure of the system. Construction is in general more complex. 19