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This article is intended to give readers an understanding of various pump parts, their purpose, applications, advantages and disadvantages.Pump and its partsA wide range of processes and applications require use of pumps for their operations in various industries. They can also be used in commercial and domestic applications.  A great variety of high pressure pumps are available in different sizes, designs and features.  Pumps play a significant role in the production process and are indispensable for smooth operations. Therefore, buying a suitable high efficiency pump requires a thorough understanding of its parts as well, so that one can buy the best pump available. Pump parts have been briefly described as below:Casing: A casing can be explained as a shell, cover or a surrounding material which protects most of the components from external damage or environmental conditions. In pumps, casing is basically used to seal it to prevent leakage and retain pressure. Impellers: An impeller is a rotating component in a pump, which is equipped with vanes or blades that rotate and moves the fluid in a pump. These vanes or blades are coupled to a shaft. When the impeller rotates, it converts the energy derived from a source i.e. motor to induce flow of the fluid. Impellers form an integral part of a pump since it creates velocity to the fluid through its blades/vanes. Impeller designs are considered as a major factor in deciding the efficiency of a pump.  There are two types of impeller: Axial flow impeller and Radial flow impeller. In axial impeller, fluid moves axially to the impeller and assist in discharge of fluid along the shaft axis. In radial flow impeller, fluid moves perpendicularly to the impeller, and is mainly used for the mixing of high viscous fluids.  Impellers are also categorized into Open and closed impeller. An open impeller has number of vanes attached to a central unit, whereas a closed impeller has a side wall on both top and bottom side of the vanes. Closed impellers are suitable for volatile, explosive fluids or abrasive solids. It is difficult to clean a closed impeller since it has to be disassembled if they get clogged. Speed preferences are more in an open impeller than a closed one. Enclosed impellers are also known as shrouded impellers. Closed Impellers can either be single shrouded or double shrouded or with no shrouds at all. In a single shrouded impeller, shroud is only on the top and the impeller vanes are open to the liquid. Whereas a double shrouded impeller has a top as well as bottom shroud. A single shrouded impeller is much less efficient than enclosed double shrouded impeller designs. Impellers can also be classified basis their suction type: In a single-suction impeller liquid enters the centre of the blades from only one direction. Whereas, in a double-suction impeller liquid enters the centre of the impeller blades from both sides simultaneously. Closed impellers are available in single suction or double suction impeller designs. Plastic, Bronze and stainless steel made impellers are widely available in the market. However, before buying, one should be aware that these are subject to corrosion, erosion and cavitation and may require maintenance and repair, whenever required. Nowadays, structural compellers are also available, which are resistant to corrosion, erosion, cavitation and are light weight as well and can operate a higher efficiency. But they are expensive in comparison.  Mechanicals Seals: These seal works as an adhesive that seals a device or joins the entire system in a machine/device/pump, and helps in preventing leakage, maintaining pressure and excluding any contamination. A failure or poor quality of a mechanical seal can result in a complete shutdown of the pump itself. A good quality strong mechanical seal ensures no leakages and helps in the overall efficiency of the pump if it is properly fitted. Mechanical seals are also considered as an integral part of a pump.These are basically of two main types: Single and Double Mechanical seal. In a single mechanical seal, there is a single seal mounted inside a pump cavity. A double mechanical seal consist of two seals which are independent to each other, where the inner seal contains the liquid/fluid in the pump and the outer seal prevents from any leakage. Double Mechanical seals are most suitable when the fluid/liquid is hazardous or when the pump needs to function with high pressure and high temperature. A double mechanical seal also helps the operator to easily identify if the primary/inner seal leaks. A single mechanical seal is not that durable as compared to a double mechanical seal and may cause an early corrosion and damage to the pump. Gas mechanicals seals are mechanical seals used primarily for high pressurized gases, to prevent them from leaking into the atmosphere. Such leakages can not only be very harmful to the operators but also to the environment.  While buying a single or double or a gas mechanical seal one must consider factors such as the liquid/fluid/substance used in the pump, pressure level, temperature, viscosity of the fluid, and the construction material which is wear resistant, low leakage, corrosion resistant and more reliable. Sometimes, a quench or vent is used behind/outside a seal so that the temperature of the liquid/fluid/vapour can be controlled in the seal area. A quench mechanical seal helps in absorption and removal of any leakage, monitoring the seal’s leakage rate, effective lubrication or cooling of the standby seal, and prevents the leakage to reach the atmosphere. Bearings: A bearing is a component that helps reduce friction on moving parts in a pump. It supports the shaft to rotate smoothly in any motion. They are commonly used in Pumps, Motors, Gearboxes, Blowers and Engines. Roller bearings are bearings that use cylindrical shape rollers between the moving parts. They reduce the friction and can support in radial or axial flow. Roller bearings are of many types such as cylindrical, tapered, needle and thrust roller bearing. All these differ in their shape, design and sizes with difference in their diameters.Ball bearings are type of bearings that uses balls to support the movement of the parts. They are simple in design and are suitable for high speeds and easy to maintain. Babbit bearings are bearings made of Babbit metal, i.e. tin or lead based alloys, and commonly used in motors, pumps, turbine generators and fans. They are available in different design and features. The shaft speed, bearing load, shaft stability, bearing cooling and overall machine load and speed are few factors that determine which Babbit bearing should be chosen.Sleeve Bearings are kind of bearings which are mostly suitable for oscillating movement and to help handle high-load and high-velocity applications. They are also known as journal bearings. They can be built of metallic alloys, sintered metals, plastics, rubber or ceramic.Pivot shoe Bearings also known as Kingsbury Bearings, consist of a shaft rotating within a shell made up of curved pads. It is ideal for high load capacity operations.Selecting a proper bearing is very crucial for the efficiency of the rotating equipment. One must consider all factors such as the process, fluid/liquid used, speed, material of the bearing etc. to choose the best one.Connecting Rod: Connecting rod is a rod which connects the piston to the crankshaft. It supports the circular or rotation movement of the crankshaft. It is mounted to a crankpin with a bearing. Because of its function it usually gets tensed, compressed, buckled or bent if good quality is not used. They are most commonly used in Pumps, Engines and Compressors.Connecting rod bearings: Connecting rod bearing helps to support or hold the crankshaft while forces and motions of high velocity take place in the working/process through the connecting rod. Pistons: it is a component used in a reciprocating pump, compressor or engines, which is tightly fitted in a cylinder and moves to compress or move the fluid/liquid. It is a lubricated sliding shaft which moves mostly back and forth, with a force to assist the production process. It is available with many manufacturers such as Gaso, Gardner Denver, Wheatley, Oilwell, and National. A piston liner is used to line the cylinder in which the piston moves, by forming a sliding surface, and facilitating the task of compression or creating pressure. Piston liners are useful since they reduce wear on the cylinder and the piston and uses lower lubrication. Plungers: Plunger has the same function as that of a pump and only differs in its shape and size. It also moves in a closed fitted cylinder in strokes. Plungers are most commonly used in positive displacement pumps. Plungers are available in variety of materials and sizes. Few of them are Rokide plunger, which uses little lubrication and is also known as Chrome Oxide. Rokide is used as a hardened coating to the base material. Ceramic plungers are also popular, made of ceramic, they are resistant to abrasive substances if used in pumps. Another type of plunger commonly used is Tungsten coated, in which a tungsten coating is done to reduce the wear and tear of the plunger. They are corrosion resistant. Few types of Hard-Co plungers are also available where the coating is of nickel chrome alloy mainly used for non-porous applications. Most common manufacturers of these kinds of plungers are National, Gaso, Gardner Denver, Oilwell, and Union.Wrist pins: A wrist pin connects the connections rod and the piston. As the piston moves, the wrist pin helps with a bearing for the connection rod and piston to move smoothly. Wrist pins are available in a variety of diameters, thicknesses, and lengths to best suit your needs.Pump Valves: Valves in a pump perform a crucial function of regulating, controlling and directing the flow of fluids in a pump. There are many types of valves available such as Disc Valve, where the valve is opened and closed by a disc and provides excellent performance for lubricated, high-speed service. AR valves known as Abrasion Resistant are suitable for applications that can cause heavy wear and tear due to the nature of fluid or high pressure/temperature. They come in stainless steel and other alloys. Other types of valves include Delrin valves, Ball valves and Cage valves. These are mostly used in Reciprocating or Diaphragm Pumps. Most common manufacturers of these valves are National, Gardner Denver, Armstrong, Standard and Aplex.Relief Valves: Also known as PRV (Pressure relief valve) or RV (Relief valve) is a type of valve used to regulate or control the pressure in a system. These are designed to open up when the pressure exceeds its predetermined limits. It is commonly used in petroleum refining, petrochemical and chemical manufacturing, natural gas processing and power generation industries and form an integral part of the process because of its crucial functioning from safety and controls point of view. They are available in different types such as Shear Pin Relief Valves, which uses one or two shear pins to set relief the pressure. They come in different sizes too. PORV (Pilot Operated Relief valves) basically uses system pressure to seal the valve. A good PORV can work with pressures up to 420 bar (6000 psi) and flows up to 400 lpm (106 gpm) in a reliable and compact design. Spring relief valves are used in applications where very high reliability and safety pressure is required such as in nuclear safety related applications. These valves open to relieve excess pressure and then reclose and prevent further flow. Ultimately, the main purpose of all these valves is to mitigate accidents and accidental damages. Taylor, Odrill, Leser, Crosby, Emerson are few of the key manufacturers of relief valves.Pressure Gauges: A pressure gauge is an instrument to measure and display pressure level. It monitors pumps discharge or inlet pressure. They should be used for all high pressure applications. Different models are available in the market in brass or stainless steel material. Couplers & Bushings: A coupler is a device which connects or links two components to avoid disconnection of shafts during operation. While selecting a coupling one needs to consider its horsepower, angular misalignment, offset misalignment, axial travels etc.Disc coupling transmits mechanical power from a driving to a driven machine. Disc couplings can accommodate large amounts of misalignment. Transmission between the bolts takes place through a series steel discs assembled in a pack. Misalignment occurs due to deforming of the material between the bolts. A gear coupling is a mechanical device, where mechanical power is transmitted between two shafts that are not collinear. It consists of a flexible joint fixed to each shaft. A spindle, which is a third shaft, is connected with the two joints. Checking and changing lubricant regularly if the coupling is lubricated is essential for a coupler’s long life. Poor coupling selection or improper installation can damage the running of the entire machine.Bushing: Bushing usually made of rubber, polyurethane or other materials is a kind of bearing used for reducing friction and wear and can form an integral part between the pump and the mechanical seal. Taper locking bushings are usually used to mount pulleys, sprockets, and sheaves on shafts. They use screws to tighten on the shaft and provide excellent clamping force. They are mostly split and flangeless bushings.Couplers and Bushings are mainly used in pumps, motors, gearboxes, blowers and engines. Few of the key manufacturers of these products are Kopeflex, TB Woods, Love Joy and John Crane.Oil Seals: Oil seal usually made of oil and grease resistant rubber is a device used for preventing leakage or entry of oil from a chamber. This seal may also be used to prevent outside materials such as dirt from moving in through the clearance. They have great use in engines, pumps, blowers, motors and gearboxes.Lip seals: Also sometimes known as Radial shaft seals, are used to seal rotary components such as a shaft or a rotating bore. Axle seals, hydraulic pump seals, or valve steam seals are few examples of lip seals.Wiper seal is an axial seal, which is used for containment of fluid and prevents dirt from entering a shaft. It is installed on the outer side of a cylinder. They are available in wide range of materials like Poly-tetra-fluoro-ethylene (PTFE) based material, elastomer, polyurethane etc. O ring seal, which is typically in O shape, closes a gap between two surfaces so that liquids or gases cannot pass through in any direction. An O ring seal, changes its shapes when pressure is applied in the system, so it squeezes and comes back to its original shape. It is different from oil seals or any other seal since it prevents the loss of fluid or gas between two components unlike any other seal which only prevents a leakage. SKF, Inpro, Timken, Parker, Koyo are some popular manufacturers of these kind of seals.There are various other parts of a pump, such as wrist pin bushings, Cross Heads, Stuffing Boxes, Shim Packs, and Wear Rings etc. Each part or component in a pump plays a very crucial role in its efficient functioning. Conversely, the cost and inconvenience of a poorly selected part can be catastrophic. We shall be happy to assist you to choose the best component for your pump. Please feel free to contact us for more information or any query.

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