4BE3 U2 C2 Review
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Questions and Answers

What is the primary focus of this chapter?

  • Pumps driven by electric motors (correct)
  • Pumps driven by steam turbines
  • Pumps driven by manual power
  • Pumps driven by internal combustion engines

What is the function of the coupling in the pump assembly?

  • To pressurize and move fluid
  • To align the pump and motor
  • To transfer mechanical energy from the electric motor to the pump (correct)
  • To convert electrical energy to mechanical energy

What happens if the pump and motor are not properly installed or aligned?

  • The pump will operate more efficiently
  • The pump will lose efficiency and may fail prematurely (correct)
  • The pump will have a longer lifespan
  • The pump will not be affected

What is the purpose of the electric motor in the pump assembly?

<p>To convert electrical energy to mechanical energy (A)</p> Signup and view all the answers

What type of pumps are shown in Figure 1?

<p>Multi-stage, centrifugal boiler feedwater pumps (C)</p> Signup and view all the answers

What happens to the pump's efficiency if parts are worn or damaged?

<p>It decreases (C)</p> Signup and view all the answers

What is the function of the metal base in a centrifugal pump?

<p>To support the motor and the pump, and keep them in proper alignment (D)</p> Signup and view all the answers

What is the purpose of the coupling in a centrifugal pump?

<p>To transmit power from the motor to the pump (B)</p> Signup and view all the answers

What is the function of the bearing cover in a centrifugal pump?

<p>To protect the bearing from dust, debris, and water (B)</p> Signup and view all the answers

What is the purpose of the slinger in a centrifugal pump?

<p>To deflect leaking fluid away from the electric motor (B)</p> Signup and view all the answers

What is the function of the shaft sleeve in a centrifugal pump?

<p>To protect the shaft from being damaged by the seal packing (D)</p> Signup and view all the answers

What is the purpose of the wear rings in a centrifugal pump?

<p>To prevent leakage between the impeller and the pump casing (D)</p> Signup and view all the answers

What is the preferred material for wear rings in centrifugal pumps?

<p>Bronze and cast iron (C)</p> Signup and view all the answers

What is the advantage of using non-metallic materials for wear rings in centrifugal pumps?

<p>They offer less scoring, wear, and expansion due to heat (C)</p> Signup and view all the answers

How are wear rings typically installed on the impeller or pump casing?

<p>By threading or shrinking (D)</p> Signup and view all the answers

What is the benefit of using wear rings in centrifugal pumps?

<p>They minimize wear and leakage, improving pumping efficiency (D)</p> Signup and view all the answers

Where can split rings be fitted to prevent axial movement?

<p>Into a groove in the pump casing (B)</p> Signup and view all the answers

What is the main purpose of sealing the shaft penetration point in a pump?

<p>To prevent environmental contamination (C)</p> Signup and view all the answers

What is the function of the gland in a stuffing box?

<p>To compress the packing (B)</p> Signup and view all the answers

Why is it necessary to have a slight amount of leakage when using compression packing?

<p>To cool and lubricate the packing (D)</p> Signup and view all the answers

What happens when the lubricant in the packing is lost and the packing shrinks away from the shaft?

<p>The fluid leakage along the shaft increases (A)</p> Signup and view all the answers

What is the purpose of the replaceable shaft sleeves when using compression packing?

<p>To take the wear from contact with the packing (A)</p> Signup and view all the answers

What can happen if the operator tightens the gland so that all fluid flow stops?

<p>The shaft and packing will heat up (D)</p> Signup and view all the answers

Why is it important for operators to have a good understanding of how compression packing works?

<p>To avoid wasted packing, scored shafts, excessive downtime, and expensive repairs (D)</p> Signup and view all the answers

What is the limitation of tightening the packing gland to stop leakage?

<p>It can only be done a limited number of times (B)</p> Signup and view all the answers

What is the function of the saturant in compression packing?

<p>To lubricate the packing and shaft (C)</p> Signup and view all the answers

What is the primary reason for over-tightening the packing gland?

<p>Due to excessive heat caused by friction (C)</p> Signup and view all the answers

What is the purpose of the lantern ring in the stuffing box?

<p>To distribute sealing water to the packing (D)</p> Signup and view all the answers

When is clean sealing water usually supplied from a separate source?

<p>When pumping water that contains sand or grit (A)</p> Signup and view all the answers

How often should pump packing be replaced?

<p>Periodically, depending on operating conditions and packing quality (A)</p> Signup and view all the answers

What is the first step in replacing pump packing?

<p>Take out a safe work permit (B)</p> Signup and view all the answers

Why is it important to count the number of rings before and after the lantern ring?

<p>To ensure the lantern ring is returned to the same place (B)</p> Signup and view all the answers

What is the formula to determine the correct size of packing to use?

<p>Bore of stuffing box - shaft diameter / 2 (A)</p> Signup and view all the answers

How should the packing rings be installed on the shaft?

<p>By sliding each ring sideways over the shaft (C)</p> Signup and view all the answers

What is the purpose of applying a light coating of oil or grease on the inner diameter of each packing ring?

<p>To facilitate installation of the packing ring (B)</p> Signup and view all the answers

Why is it important to ensure the ring joints are staggered during packing installation?

<p>To ensure the lantern ring lines up properly (C)</p> Signup and view all the answers

What is the primary function of the pump in a driver and pump assembly?

<p>To transfer mechanical input energy into work done to pressurize and move fluid (A)</p> Signup and view all the answers

What is the result of careful installation, proper alignment, and operation within normal parameters of a new motor and pump?

<p>The pump will operate smoothly, efficiently, and have a long life (D)</p> Signup and view all the answers

What happens to the pump's efficiency if its parts are out of alignment, poorly installed, damaged, or worn?

<p>The pump's efficiency will decrease (D)</p> Signup and view all the answers

What is the common feature of the electric motor-driven pumps shown in Figure 1?

<p>They are all multi-stage, centrifugal boiler feedwater pumps (D)</p> Signup and view all the answers

What is the purpose of the electric motor in the pump assembly?

<p>To convert electrical energy into mechanical energy (D)</p> Signup and view all the answers

What is the condition required for the pump to operate smoothly, efficiently, and have a long life?

<p>The pump and motor must be new, carefully installed, properly aligned, and operating within their normal parameters (B)</p> Signup and view all the answers

What is the primary function of the bearings in a centrifugal pump?

<p>To support and guide the shaft, and reduce friction (D)</p> Signup and view all the answers

What is the purpose of the seal cover or stuffing box in a centrifugal pump?

<p>To hold the seal and prevent fluid from leaking out (D)</p> Signup and view all the answers

What is the benefit of using wear rings with a tighter fit in centrifugal pumps?

<p>Improved pumping efficiency due to reduced friction (B)</p> Signup and view all the answers

What is the purpose of the lantern ring in a centrifugal pump?

<p>To provide water to the packing to keep it cool and lubricated (C)</p> Signup and view all the answers

What is the primary function of the shaft in a centrifugal pump?

<p>To transmit power from the motor to the pump (B)</p> Signup and view all the answers

What is the purpose of the bearing housing in a centrifugal pump?

<p>To hold the bearing and support the shaft (A)</p> Signup and view all the answers

What is the primary reason for using wear rings in centrifugal pumps?

<p>To prevent wear of the impeller and the pump casing (D)</p> Signup and view all the answers

What is the function of the coupling in a centrifugal pump?

<p>To transmit power from the motor to the pump (A)</p> Signup and view all the answers

What is the advantage of using bronze and cast iron for wear rings in centrifugal pumps?

<p>They tend to wear in a smooth manner (A)</p> Signup and view all the answers

What is the purpose of the metal base in a centrifugal pump?

<p>To support the motor and the pump, and keep them in proper alignment (A)</p> Signup and view all the answers

What is the primary reason for using compression packing in pump shaft sealing?

<p>To restrict leakage while allowing for cooling and lubrication (D)</p> Signup and view all the answers

What is the purpose of the lubricant in compression packing?

<p>To compensate for lost lubrication when the packing shrinks (D)</p> Signup and view all the answers

What happens when the operator tightens the gland to stop all fluid flow?

<p>The shaft and packing heat up due to friction (D)</p> Signup and view all the answers

What is the limitation of tightening the packing gland to stop leakage?

<p>The lubricant in the packing will be depleted (A)</p> Signup and view all the answers

What is the purpose of replaceable shaft sleeves in compression packing?

<p>To take the wear from contact with the packing (B)</p> Signup and view all the answers

Why is it necessary to have a slight amount of leakage when using compression packing?

<p>To cool and lubricate the packing (A)</p> Signup and view all the answers

What happens when the lubricant in the packing is lost and the packing shrinks?

<p>The leakage along the shaft increases (C)</p> Signup and view all the answers

What is the purpose of the gland in a stuffing box?

<p>To compress the packing (A)</p> Signup and view all the answers

What is the primary focus of this chapter?

<p>Pump shaft sealing methods (B)</p> Signup and view all the answers

Why is it important for operators to have a good understanding of how compression packing works?

<p>To avoid wasted packing, scored shafts, and downtime (C)</p> Signup and view all the answers

What is the primary consequence of over-tightening the packing gland?

<p>Scoring of the shaft and burning of the packing (D)</p> Signup and view all the answers

What is the purpose of the sealing water connection in the stuffing box?

<p>To prevent air leakage into the casing (C)</p> Signup and view all the answers

Why is it important to ensure the lantern ring is returned to the same position during packing replacement?

<p>To ensure the seal water opening and the lantern ring line up (B)</p> Signup and view all the answers

What is the recommended step after shutting down the pump during packing replacement?

<p>Isolate and drain the pump (D)</p> Signup and view all the answers

What is the consequence of not replacing the shaft sleeve when it is scored or grooved?

<p>Damage to the new packing (B)</p> Signup and view all the answers

What is the purpose of applying a light coating of oil or grease on the inner diameter of each packing ring?

<p>To reduce friction between the packing and the shaft (D)</p> Signup and view all the answers

Why is it important to stagger the ring joints during packing installation?

<p>To ensure even distribution of stress and pressure (D)</p> Signup and view all the answers

What is the recommended method for cutting the packing to the correct size?

<p>Wrapping a coil of packing around a rod and cutting through each turn (A)</p> Signup and view all the answers

What is the purpose of the lockout/tagout procedure during packing replacement?

<p>To prevent accidental startup of the pump (D)</p> Signup and view all the answers

What is the consequence of not properly cleaning the stuffing box before installing new packing?

<p>Premature failure of the new packing (B)</p> Signup and view all the answers

What is the primary advantage of mechanical seals over packing?

<p>They require much less maintenance. (D)</p> Signup and view all the answers

What is the function of the spring in a mechanical seal?

<p>To hold the sealing ring in place. (B)</p> Signup and view all the answers

What is the main difference between a rotating and stationary mechanical seal?

<p>Whether the sealing ring or mating ring rotates. (B)</p> Signup and view all the answers

What is the consequence of a mechanical seal failure?

<p>The pump must be taken out of service for a longer period. (D)</p> Signup and view all the answers

What is the purpose of the shell in a rotating mechanical seal?

<p>To fasten the seal to the pump shaft. (B)</p> Signup and view all the answers

What is the disadvantage of mechanical seals compared to packing?

<p>They have a greater initial cost. (C)</p> Signup and view all the answers

What is the primary function of the stationary mechanical seal?

<p>To prevent leakage between the shaft and the sealing ring (A)</p> Signup and view all the answers

What is the consequence of running a mechanical seal dry?

<p>The sealing surfaces will become overheated, grooved, and scored (A)</p> Signup and view all the answers

What is the purpose of the 'O' ring gaskets in a stationary mechanical seal?

<p>To prevent leakage between the shaft and the mating ring (C)</p> Signup and view all the answers

What is the common material used for the sealing and mating rings in a mechanical seal?

<p>Bronze (B)</p> Signup and view all the answers

What is the primary purpose of flexible couplings in pump and motor installations?

<p>To compensate for unavoidable misalignment during operation (C)</p> Signup and view all the answers

What is the purpose of the bearings in a centrifugal pump?

<p>To hold the shaft in place and support it (B)</p> Signup and view all the answers

What is the benefit of using flexible couplings to connect the pump and motor?

<p>To prevent misalignment of the shafts (D)</p> Signup and view all the answers

Why are some equipment intentionally misaligned during installation?

<p>To compensate for temperature changes during operation (A)</p> Signup and view all the answers

What is the purpose of the spider-like insert in a jaw type coupling?

<p>To allow for minor misalignment during operation (A)</p> Signup and view all the answers

What is the consequence of misalignment of the pump and motor shafts?

<p>Increased power consumption (A)</p> Signup and view all the answers

What is the purpose of venting all air from the seal housing before startup?

<p>To prevent dry running of the seal (C)</p> Signup and view all the answers

What is the limitation of using a straight edge and tapered feeler gauges for alignment?

<p>They can only be used for certain types of couplings (B)</p> Signup and view all the answers

What is the advantage of using laser alignment over other methods?

<p>It is more precise and less open to interpretation (A)</p> Signup and view all the answers

What can cause misalignment of the pump and motor shafts during operation?

<p>All of the above (D)</p> Signup and view all the answers

What is the purpose of the pump bearings in both radial and axial directions?

<p>To support the shaft in both radial and axial directions (C)</p> Signup and view all the answers

What information is stored in the computer during laser alignment?

<p>The alignment data, pump and motor nameplate information, and equipment numbers (A)</p> Signup and view all the answers

What is the purpose of inserting shims under the feet of the pump or motor during alignment?

<p>To raise or lower the pump or motor to achieve proper alignment (D)</p> Signup and view all the answers

What is the benefit of using micrometer dial indicators for alignment?

<p>They are more accurate than other methods (B)</p> Signup and view all the answers

What is the primary purpose of checking alignment during operation?

<p>To ensure proper operation and prevent damage to the equipment (C)</p> Signup and view all the answers

What is the consequence of not ensuring proper alignment during operation?

<p>The equipment may be damaged or fail prematurely (B)</p> Signup and view all the answers

What is the primary purpose of priming a centrifugal pump?

<p>To prevent the pump from running dry (C)</p> Signup and view all the answers

What is the function of the foot valve in the pump suction line?

<p>To prevent water from flowing back into the suction line (C)</p> Signup and view all the answers

What can happen if a centrifugal pump is not properly primed?

<p>The pump's impeller will churn air instead of producing suction (A)</p> Signup and view all the answers

What is the purpose of the conical or cylindrical mesh strainer in the suction line?

<p>To prevent abrasive particles from reaching the pump (C)</p> Signup and view all the answers

What should be checked during and after installation to prevent troubles during initial start-up of a centrifugal pump?

<p>All of the above (D)</p> Signup and view all the answers

What is the consequence of not properly priming a centrifugal pump?

<p>Serious damage will occur to the pump (B)</p> Signup and view all the answers

What is the purpose of the air vent valves in the pump casing?

<p>To allow air to escape from the pump casing (C)</p> Signup and view all the answers

What can happen if the pump and driver are not properly installed or aligned?

<p>Troubles will develop during initial start-up (B)</p> Signup and view all the answers

What is the primary purpose of the pump suction line?

<p>To allow water to flow into the pump casing (A)</p> Signup and view all the answers

What should be done before starting a centrifugal pump for the first time?

<p>Make a thorough check of the unit (C)</p> Signup and view all the answers

What is the purpose of cleaning the screens several times during the first few days of operation?

<p>To prevent clogging of the screens (A)</p> Signup and view all the answers

Why is it necessary to recheck the pump alignment after it has run for a short time?

<p>To account for the change in temperature that may have affected the alignment (A)</p> Signup and view all the answers

What is the purpose of the pressure relief device in the discharge line of a positive displacement pump?

<p>To relieve fluid back to the storage tank (D)</p> Signup and view all the answers

What is the recommended step before starting the pump?

<p>Prepare the system that provides cooling water for pump bearings (D)</p> Signup and view all the answers

What is the consequence of not properly aligning the pump and its driver?

<p>The pump may not operate efficiently (D)</p> Signup and view all the answers

What is the purpose of turning the pump over by hand?

<p>To check for any binding, scraping, or noise (A)</p> Signup and view all the answers

What is the purpose of inspecting the pump footings?

<p>To ensure any devices for expansion of the casing are free and in good working condition (C)</p> Signup and view all the answers

What is the purpose of flushing the bearing housing with solvent?

<p>To clean the bearing parts (A)</p> Signup and view all the answers

Why is it important to check the rotation of the pump shaft?

<p>To ensure the pump shaft is turning in the correct direction (D)</p> Signup and view all the answers

What is the purpose of checking the flow of the sealing liquid to the packing or mechanical seals?

<p>To ensure the packing or mechanical seals are functioning correctly (C)</p> Signup and view all the answers

What is the main characteristic of positive displacement pumps that enables them to develop considerable discharge pressure and vacuum at their suction inlet?

<p>Minute clearance between the pressure-imposing element and the pump housing (D)</p> Signup and view all the answers

Why are positive displacement pumps considered self-priming?

<p>Because they can develop great suction lift (C)</p> Signup and view all the answers

What is the benefit of running pumps when full of liquid?

<p>It cools and lubricates the internal pump surfaces, reducing wear (D)</p> Signup and view all the answers

What is the purpose of the air vent in some positive displacement pumps?

<p>To allow for priming (C)</p> Signup and view all the answers

What is the first step in shutting down a pump?

<p>Turn the pump off (C)</p> Signup and view all the answers

What should operators review and understand before starting, operating, or stopping pumps?

<p>Site-specific procedures (A)</p> Signup and view all the answers

What should be checked prior to removing a lockout on a positive displacement pump?

<p>The piping connections and valve positions (B)</p> Signup and view all the answers

What should be monitored after starting a pump?

<p>The suction and discharge pressures, pump temperature, and pump vibration (B)</p> Signup and view all the answers

What is the purpose of routine checks on pumps?

<p>To identify problems in their early stages (A)</p> Signup and view all the answers

What is the result of not properly priming a positive displacement pump?

<p>The pump will not start (C)</p> Signup and view all the answers

What is the primary advantage of mechanical seals over packing in terms of shaft maintenance?

<p>Less wear on shafts and shaft sleeves (A)</p> Signup and view all the answers

What is the purpose of the spring in a mechanical seal?

<p>To hold the sealing ring in position (A)</p> Signup and view all the answers

What is the characteristic of the rotating mechanical seal that prevents leakage?

<p>The rotating sealing ring is forced against the mating ring (A)</p> Signup and view all the answers

What is the disadvantage of mechanical seals compared to packing in terms of maintenance?

<p>They require less maintenance but have a longer downtime when replaced (D)</p> Signup and view all the answers

What is the characteristic of mechanical seals that allows them to work under high temperatures and pressures?

<p>Their design features (B)</p> Signup and view all the answers

What is the relationship between the sealing ring and the mating ring in a mechanical seal?

<p>The sealing ring is in contact with the mating ring (A)</p> Signup and view all the answers

What is the primary reason for priming a centrifugal pump before starting it?

<p>To prevent the impeller from churning air instead of producing suction (A)</p> Signup and view all the answers

What is the purpose of the foot valve in the suction line of a centrifugal pump?

<p>To allow water to enter the suction line but prevent it from flowing back out (D)</p> Signup and view all the answers

What can happen if a centrifugal pump is not properly primed?

<p>The pump will experience serious damage and wear (A)</p> Signup and view all the answers

Why is it important to install a conical or cylindrical mesh strainer in the suction line of a centrifugal pump?

<p>To prevent abrasive particles from reaching the pump (D)</p> Signup and view all the answers

What is the main purpose of 'O' ring gaskets in the mechanical seal?

<p>To prevent leakage between the shaft and the mating ring, and between the sealing ring and housing (A)</p> Signup and view all the answers

What is the primary cause of scored or grooved seal faces in a mechanical seal?

<p>Running the pump in a dry condition (C)</p> Signup and view all the answers

What should be checked during and after installation to prevent troubles during initial start-up of a centrifugal pump?

<p>All of the above (D)</p> Signup and view all the answers

What is the purpose of the air vent valves in the pump casing?

<p>To allow air to escape from the pump casing (D)</p> Signup and view all the answers

What is the main purpose of the bearings in a centrifugal pump?

<p>To hold the shaft in place and support it (B)</p> Signup and view all the answers

What can happen if the suction pressure gauge indicates a drop in suction pressure during initial start-up of a centrifugal pump?

<p>The strainer is plugging (A)</p> Signup and view all the answers

What is the primary advantage of using flexible couplings in pump and motor installations?

<p>To protect the machinery against the negative results of misalignment (A)</p> Signup and view all the answers

What is the primary reason why some equipment is misaligned intentionally during installation?

<p>To ensure proper alignment during temperature changes (A)</p> Signup and view all the answers

What is the purpose of the priming water in the priming process of a centrifugal pump?

<p>To fill the pump casing and suction line with liquid (C)</p> Signup and view all the answers

What is the primary consequence of misalignment of the pump and motor shafts?

<p>Severe bending stresses in the shafts, leading to shaft failure (C)</p> Signup and view all the answers

What is the main purpose of the stationary sealing ring in a mechanical seal?

<p>To press against the rotating mating ring, preventing leakage between the two faces (D)</p> Signup and view all the answers

What should be done before starting a centrifugal pump for the first time?

<p>All of the above (D)</p> Signup and view all the answers

What is the limitation of using a straight edge and tapered feeler gauges for alignment?

<p>It cannot be used for all types of couplings (B)</p> Signup and view all the answers

What is the purpose of a spider-like insert in a jaw type coupling?

<p>To dampen vibration and allow for end float of the shafts (D)</p> Signup and view all the answers

What is the primary reason for using materials like bronze, carbon graphite, and ceramics for the sealing and mating rings in a mechanical seal?

<p>To vary depending on the type of liquid being pumped, fluid temperature, and fluid pressure (D)</p> Signup and view all the answers

Why is it important to properly install a centrifugal pump?

<p>To prevent troubles during initial start-up (B)</p> Signup and view all the answers

What is the advantage of using laser alignment over other methods?

<p>It is more precise and less open to interpretation (D)</p> Signup and view all the answers

What is the primary cause of excessive bearing wear in a centrifugal pump?

<p>Misalignment of the pump and motor shafts (D)</p> Signup and view all the answers

What is the main purpose of venting all air from the seal housing before startup?

<p>To prevent overheating of the sealing surfaces (A)</p> Signup and view all the answers

What is the purpose of inserting shims under the feet of the pump or motor during alignment?

<p>To raise or lower the pump or motor to achieve proper alignment (A)</p> Signup and view all the answers

What is the primary consequence of distortion of the pump parts caused by misalignment of piping?

<p>Leaking seal (A)</p> Signup and view all the answers

What is the result of not properly aligning the pump and motor shafts during operation?

<p>The equipment will vibrate excessively (A)</p> Signup and view all the answers

What is the purpose of the micrometer dial indicator in the alignment process?

<p>To measure the offset and angular misalignment of the shafts (D)</p> Signup and view all the answers

What is the benefit of using flexible couplings in pump and motor installations?

<p>They allow for a limited amount of angular misalignment (B)</p> Signup and view all the answers

What is the purpose of checking the alignment of the pump and motor shafts after adjustments are made?

<p>To ensure that the equipment is properly aligned (D)</p> Signup and view all the answers

What is the primary function of the laser in laser alignment?

<p>To transmit precise measurements to a hand-held computer (D)</p> Signup and view all the answers

What is the primary reason for removing the screens during the first few days of operation?

<p>To prevent clogging of the pump (C)</p> Signup and view all the answers

What is the consequence of not checking the pump alignment after it has run for a short time?

<p>The alignment may change due to temperature change (D)</p> Signup and view all the answers

What is the purpose of the pressure relief device in the discharge line of a positive displacement pump?

<p>To relieve fluid back to the storage tank (D)</p> Signup and view all the answers

What is the recommended procedure for inspecting pump bearings before starting the pump?

<p>Inspect the condition of the grease by removing the bearing housing cover (B)</p> Signup and view all the answers

What is the primary purpose of supporting the connected piping properly?

<p>To prevent the pump from supporting the weight of the connected piping (B)</p> Signup and view all the answers

What is the consequence of not closing all drains in the casing, suction, and discharge piping before starting the pump?

<p>The pump will not be properly primed (D)</p> Signup and view all the answers

What is the primary purpose of turning the pump over by hand before starting it?

<p>To ensure the pump turns freely without binding, scraping, or making any noise (C)</p> Signup and view all the answers

What is the recommended step before starting a positive displacement pump?

<p>Line up the pump valves according to the priming procedure required (C)</p> Signup and view all the answers

What is the primary purpose of inspecting the pump footings before starting the pump?

<p>To ensure that any devices for expansion of the casing are free and in good working condition (C)</p> Signup and view all the answers

What is the consequence of not adjusting the flow of the sealing liquid to the packing or mechanical seals after starting the pump?

<p>Leakage may occur from the stuffing boxes (B)</p> Signup and view all the answers

Why are positive displacement pumps considered self-priming?

<p>Because they can develop great suction lift (B)</p> Signup and view all the answers

What is the primary benefit of running positive displacement pumps when full of liquid?

<p>It cools and lubricates the internal pump surfaces (C)</p> Signup and view all the answers

What should be checked prior to removing a lockout on a positive displacement pump?

<p>The piping connections and valves (B)</p> Signup and view all the answers

Why is it advisable to manually prime rotary positive displacement pumps before starting?

<p>Because they may not develop great suction lift like reciprocating pumps (C)</p> Signup and view all the answers

What should be monitored during post-start checks on a positive displacement pump?

<p>The pump's suction and discharge pressures (D)</p> Signup and view all the answers

What is the purpose of the air vent valves in some positive displacement pumps?

<p>To release air from the pump (B)</p> Signup and view all the answers

What is the primary focus of the pre-start checks on a positive displacement pump?

<p>To ensure the pump is properly primed and ready to operate (B)</p> Signup and view all the answers

What is the result of not performing routine checks on a positive displacement pump?

<p>Problems may not be identified until they become major issues (D)</p> Signup and view all the answers

What is the primary reason for performing post-start checks on a positive displacement pump?

<p>To ensure the pump is operating within normal parameters (C)</p> Signup and view all the answers

What is the final step in shutting down a positive displacement pump?

<p>Closing the discharge valve (A)</p> Signup and view all the answers

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