Mechanical Seals & Pumps

 Advantages Reduced Friction And Loss of Power Negligible Product Leakage Elimination Of Excessive Wear Maintenance Reduced Long Term Cost Effectiveness Disadvantages Less tolerant to shaft deflection and misalignment  High beginning expense The structure is relatively complex Require workers to have a certain level of installation skills. Less tolerant to dirty or contaminated liquid, Require expensive seal piping to flush and quench                               Causes of the Pump Failures     Mechanical seal failure - 60 to 70% Bearings failure- 15 to 25% Pumping rate 5 to 10% Miscellaneous 5 to 15%

  Balancing flow is passed through the space between its rotating and non-rotating portions when the pump is running. The balancing flow experiences significant throttling as it passes through the gap. This pressure loss produces an axial force to act on the balancing device, counteracting the axial thrust of the impeller and achieving the necessary balance. If the balancing device consists of a balance disc, the entire axial thrust of the pump rotor is usually balanced. In this case, an additional thrust bearing is not required      Balancing device with balance drum                                    Balancing device with balance drum Balancing device with double drum   Other Balancing arrangements : Mechanical: complete absorption of the axial thrust via a thrust bearing Design-based: back-to-back arrangement of the impellers  Balancing or reduction of the axial thrust on the individual impeller via Balancing holes Reduction at the individual impeller by back vanes  Balancin

  Multistage pumps are utilized in locations that demand high pressure, such as application of boiler feed water. These pumps have a series arrangement of the impellers, which creates high pressure, which leads to high axial thrust. Additional devices are employed to balance the axial thrust since thrust bearings alone cannot withstand the load. Arrangements used for balancing are – Balancing Disc Balance drum Double drum HGC high-pressure multi-stage pump

 Shaft : The pump shaft transmits the drive torque to the impellers to centrifugal pumps  The impellers, shaft sleeves, bearings, couplings, and other parts are carried by the pump shaft In centrifugal pump engineering, both rigid and flexible shaft couplings are used. Rigid couplings are mainly used to connect shafts in perfect alignment & Flexible couplings are elastic, slip-free connecting elements between drive and pump which accommodate axial, radial and angular misalignment and damp shock load                                                             Exploded View of MegaCPK Bearing: The pump bearings sustain the loads brought on by the shaft coupling or belt drive, the hydraulic loads imposed on the impeller, the mass of the impeller and shaft etc. The fluid's hydraulic and momentum forces make up the hydraulic loads. Axial load and radial load are the two components of the forces acting on the impeller. The three most used ball bearing types are the single row deep gr

  The diffuser is a part that, with the least amount of loss feasible, reduces flow velocity and raises static pressure in response. A diffuser's distinguishing characteristic is a flow path with increasing cross-sectional area in the direction of flow, in a closed duct or channel The vane angle for either volute or diffuser, if properly designed, is correct for only the capacity at the BEP. If the pump is operated at some other capacity, the diffuser may act as a hindrance rather than as an aid to efficient operation.

  The specific speed of centrifugal pump is defined as speed of geometrical Similar pump which would deliver one cubic meter of liquid per second against head of one meter It is a function of shaft speed, flow rate, and differential head at the pump Best Efficiency Point  Sp.Speed It is a key consideration in the design and selection of pumps, and particularly pump impellers , is specific speed.

  Volute of a centrifugal pump is the casing that receives the fluid being pumped by the impeller As liquid exits the impeller it has high kinetic energy and the volute directs this flow through to the discharge.  As the fluid travels along the volute it is joined by more and more fluid exiting the impeller but, as the cross sectional area of the volute increases, and velocity is gradually reduces. Volute casings come in three different types:  Single volute and Double volute The fundamental benefit of a double volute over a single volute is the equalization of the pressure distribution within the volute. Radial thrust can substantially increase the pump shaft deflection Pressure distribution comparison  for non diffuser volute casing The motional energy of one or more driven rotors, known as impellers, is transferred to power a centrifugal pump.  The fluid is directed toward the pump output by the impeller's movement, which raises its pressure and velocity. Depending on the flow l

  When water enters the casing (Inlet Nozzle), the impeller begins to rotate. As a result, the fluid inside the impeller also rotates, creating a centrifugal force that causes the fluid to move toward the inner peripheral surface of the casing. Eventually, a higher pressure is created at the inner peripheral surface, and at a suitable point (Discharge Nozzle), the fluid exits the casing. The action of the impeller increases the fluid’s velocity and pressure and also directs it towards the pump outlet.                 Labelled Diagram:    Mega CPK-Chemical Process Pump    

  Numerous components make up each centrifugal pump. Many centrifugal pumps share a few parts in common. These parts can be split into the mechanical end and the wet end. The wet end of the pump includes those parts that determine the hydraulic performance of the pump. The two primary parts of wet end are the impeller and casing . The components that hold the impeller within the casing are part of the mechanical end. The Pump shaft, Mechanical seals, Bearings, Bearing housing etc. are all part of the mechanical end of the device. Hydraulic & Mechanical assembly & CPK-Chemical Process Pump

  Centrifugal pump is used to transport fluid by conversion of rotational kinetic energy into hydrodynamic energy of the fluid flow. It is the hydraulic machines which converts the mechanical energy into hydraulic energy. This hydraulic energy is in the form of pressure energy. These pumps work by using a rotating impeller to create a centrifugal force that drives the fluid out of the pump and into the desired location. Centrifugal Pumps are used in various Industries as follow : Chemical industry  Petrochemical industry Process engineering Refinery Renewable energy Food industry  Sugar industry Steel industry Oil and Gas KSB-Etanorm Pump

API Plan 54 Pressurized external barrier fluid circulation from a central pressure source or by a stand alone pumping unit Required Media Characteristic- Suspended solids Polymerizing and contaminated media Poor lubrication properties Hazardous / environmentally harmful Leakage may form solids Close to vaporization point Can tolerate dilution with barrier media Feature - Ensures higher flow rate, better heat dissipation and positive circulation of barrier fluid. Uses a pump to ensure barrier liquid circulation and pressurization. API Plan 62                            Required Media Characteristic- Caustic & Crystalizing Fluid Oxidizing fluids Polymerizing fluid High temperature Leakage may form solids Feature - Quench stream is brought from an external source to the atmospheric side of the seal faces It cools the seal faces and  reduce cooking, oxidation, Crystallization etc. Depending on the kind of bushing the quench stream can be low pressure steam, nitrogen or clean wat