PUMP

          Pump is a mechanical device used to transfer different fluids from one position to another. It is a hydraulic device that lifts a fluid from a low to a high level and moves it from a low-pressure area to a high-pressure area. Pumps transfer fluids by converting the mechanical energy of the fluid into pressure energy.

         When a pump contains two or more pump mechanisms with fluid being directed to flow through them in series, it is called a multi-stage pump. Terms such as two-stage or double stage may be used to describe the number of stages. A pump that does not fit this description is simply a single stage pump in contrast.

Classification of pumps

• 1.Positive displacement pump
• 2.Dynamic pumps / Roto dynamic pumps
• Other pumps

 

1. 1.Positive Displacement Pumps

        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 pump can be classified into 2:

• 1.1 Reciprocating Pump
• 1.2 Rotary Pump

• 1.1 Reciprocating Pump

         A reciprocating pump is a class of positive-displacement pumps that includes the piston pump, plunger pump, and diaphragm pump. Well maintained, reciprocating pumps can last for decades. Unmaintained, however, they can succumb to wear and tear. 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 that traps the liquid is a stationary cylinder that contains a piston or plunger.

     1.1.1 Piston pumps

           These are types of pumps where the high pressure seal reciprocates with the piston.

     1.1.2 Plunger pumps

         These are types of pumps where the high pressure seal is fixed and a smooth cylindrical plunger slides through the seal.

     1.1.3 Bucket pumps / Hand pumps

         A bucket pump is a single acting vertical reciprocating pump. The bucket pump is a hand operated force pump and mainly used in drilled wells.

     1.1.4 Diaphragm pumps

         Diaphragm pump uses  rubber membrane and works on air displacement principle.

• 1.2 Rotary Pumps

           These pumps move fluid using a rotating mechanism that creates a vacuum that captures and draws in the liquid. Rotary pumps are very efficient because they can handle highly viscous fluids with higher flow rates as viscosity increases. The nature of the pump requires 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.

1.2.1  Gear pumps

       Gear pump are consist of two or more gears which mesh each other to push the liquid.

1.2.2  Vane pumps

       It consists of stationary casing and a cylindrical rotor. The cylindrical rotor contains the sliding vanes which fitted to the radial grooves of rotor.

1.2.3  Screw pumps

       Screw pumps use one or several screws to move fluid solids or liquids along the screw axis.

1.2.4  Lobe pumps

       Lobe pumps use two or more lobes rotating around parallel shafts in the pump’s body to move liquids.

1.2.5  Progressive cavity pumps

       progressive cavity pump is a positive displacement pump ,using an eccentrically rotating single-helical rotor, turning inside a stator.

1.2.6  Peristaltic pumps

A peristaltic pump, also known as a roller pump, is used to transport liquid without the contents coming into contact with the pump components.

2. 2. Dynamic Pumps / Roto Dynamic Pumps

           A rotodynamic pump is a kinetic machine in which energy is continuously imparted to the pumped fluid by means of a rotating impeller, propeller, or rotor, in contrast to a positive-displacement pump in which a fluid is moved by trapping a fixed amount of fluid and forcing the trapped volume into the pump’s discharge. Examples of rotodynamic pumps include adding kinetic energy to a fluid such as by using a centrifugal pump to increase fluid velocity or pressure.

• 2.1 Centrifugal pumps
• 2.2 Vertical centrifugal pumps
• 2.3 Horizontal centrifugal pumps
• 2.4 Fire hydrant pumps
• 2.5 Peripheral pumps
• 2.6 Submersible pumps

2.1.  Centrifugal Pumps

          These types of pumps are the most commonly used in the world. The work is very simple, well described and carefully tested. These pumps are robust, efficient and fairly inexpensive to manufacture. Whenever the pump is running, the fluid pressure will increase from the pump’s inlet to its outlet. The change in pressure will drive the fluid throughout the system.

          A centrifugal pump is of a very simple design. The two main parts of the pump are the impeller and the diffuser. Impeller, which is the only moving part, is attached to a shaft and driven by a motor. Impellers are generally made of bronze, polycarbonate, cast iron, stainless steel as well as other materials. The diffuser (also called as volute) houses the impeller and captures and directs the water off the impeller. Water enters the center (eye) of the impeller and exits the impeller with the help of centrifugal force. As water leaves the eye of the impeller a low-pressure area is created, causing more water to flow into the eye. Atmospheric pressure and centrifugal force cause this to happen. Velocity is developed as the water flows through the impeller spinning at high speed. The water velocity is collected by the diffuser and converted to pressure by specially designed passageways that direct the flow to the discharge of the pump, or to the next impeller should the pump have a multi-stage config.

2.1.1  Radial flow pumps

       Radial flow pumps are centrifugal pumps ,at which the fluid handled leaves the impeller in a radial direction. It provides high pressure at low flow rate.

2.1.2  Axial flow pumps

       Axial flow pumps basically consists of a propeller (an axial impeller) in a pipe. It provides high flow rate at low pressure.

2.1.3  Mixed flow pumps

       Mixed flow pumps are a combined version of both radial flow pumps and axial flow pumps. It provides medium flow rate at medium pressure.

2.2.  Vertical Centrifugal Pumps

        A vertical centrifugal pump has a vertically oriented shaft. The design of the shaft is radial split and overhang. Vertical centrifugal pumps are apt when you have a limited surface area. They are perfect for liquids with high temperatures and pressure and have a wide range of applications.

        The vertical centrifugal pumps get coupled with electric motors. The impeller gets connected over the shaft with the electric motor that rotates at a predefined speed and produces a centrifugal effect. These vertical centrifugal pumps are operated by a direct-drive motor and have high-performance data regarding flow rate.

2.3.  Horizontal Centrifugal Pumps

          A horizontal centrifugal pump is a type of pump that uses centrifugal force to move fluids. It is called “horizontal” because its shaft and impeller are oriented horizontally, meaning the pump’s inlet and outlet are on the same horizontal plane. These pumps are widely used in various industrial, commercial, and residential applications for fluid transfer, water circulation, and process pumping.

2.4  Fire Hydrant Pumps

             Fire hydrant pump systems are also known as fire hydrant booster, fire pump and fire pump. These are high pressure pumps designed to increase the firefighting capacity of a building by increasing the force within the hydrant service, as the mains are not sufficient. Applications for this system include mainly irrigation and water distribution.

2.5  Peripheral Pumps

         Peripheral pumps (regenerative or turbine pumps) have a similar appearance to a centrifugal pump.

2.6  Submersible Pumps

            A submersible pump is a versatile and efficient device designed for pumping fluids, typically water, from submerged locations such as wells, boreholes, or reservoirs. Unlike traditional pumps that are placed above ground, submersible pumps are specifically designed to be immersed directly in the fluid they are intended to pump. This unique design allows for enhanced efficiency, as there is no need for suction to draw the fluid into the pump. Instead, the submersible pump pushes the fluid to the surface using impellers and a sealed motor. Submersible pumps are widely used in various applications, including irrigation, dewatering, wastewater management, groundwater extraction, and even in residential and industrial settings for supplying water.

3. Other Pumps

 

3.1  Jet pumps

          Jet pumps, also known as ejector pumps, are devices capable of handling and transporting all forms of motive fluid including gas, steam, or liquid. They can be considered mixers or circulators, since the intake combines multiple fluid sources.

3.2  Electromagnetic Pumps

         An electromagnetic pump is a pump that moves liquid metal, molten salt, brine, or other electrically conductive liquid using electromagnetism. A magnetic field is set at right angles to the direction the liquid moves in, and a current is passed through it. This causes an electromagnetic force that moves the liquid. Applications include pumping molten solder in many wave soldering machines, pumping liquid-metal coolant, and magnetohydrodynamic drive.

3.3  Valveless Pumps

       Valveless pumping assists in fluid transport in various biomedical and engineering systems. In a valveless pumping system, no valves (or physical occlusions) are present to regulate the flow direction.

3.4  Vacuum Pumps

       A vacuum pump is a type of pump device that draws gas particles from a sealed volume in order to leave behind a partial vacuum.