Pumps Flashcards
What are the two classifications of positive displacement pumps?
Reciprocating and Rotary
A plunger pump is often found in a situation requiring what?
Measured flow
Piston and plunger pumps are best suited for what?
Low flow and high suction lift.
A double acting pump discharges fluid when?
On every stroke
The type of sealing mechanisms are used in plunger pumps?
V or U ring packing
Which check valve is used for moderate to high pressures?
Wing-guided
What is the term for the vertical distance from the liquid supply level to the surface of the liquid in the discharge tank or point of discharge?
Total static head
Name a pump that can function in explosive enviroments.
Pneumatic Diaphragm Pumps
The _______ has two opposite rotated, externally cut gears inside one casing.
External gear pump
The gears of an internal gear pump are seperated on one side by a _________.
Cresent
The ______ has two rotors in a casing with a set of external timing gears which synchronizes them.
Lobe Pump
Wear rings are found in a centrifugal pump attached to ________.
The eye of the impeller and the casing.
A mixed flow impeller is used to convert _______.
To convert axial fluid flow into radial fluid flow.
The maximum theoretical depth that a pump can “lift” water is approximately _______.
34ft
In a centrifugal pump, the purpose of the volute in the discharge is to _______.
Increase Output Pressure
The flow from a rotary style positive displacement pump is considered to be what?
Continuous and Smooth
A fixed displacement pump will always provide what?
Constant volume at a given speed.
What type of vane pump only has one sliding vane?
An external vane pump
A single screw pump consists of what two parts?
Rotor and Stator
How many rotors does a lobe pump have?
2
What application are centerline mounted pumps best suited for?
Pumping hot fluids
What type of impeller has the lowest specific speed?
Radial Flow
What should the area of a suction strainer be relative to suction piping
3 - 4 times larger
What is a major advantage positive displacement pumps are considered to have?
They are self-priming
How many check valves are in a single acting piston pump?
2
What is scalloping?
The removal of material between vanes.
What is the most common type of centrifugal pump in the industry?
Single stage end suction
What is the shape of the case that the rotor of a balanced vane pump turns inside of?
Elliptical
What type of pump has a part named stripper?
Regenerative Turbine
What is another name for a flexable tube pump?
Peristaltic
The number of stages a pump has is determined by what?
Number of impellers
The blades of an impeller are designed to what?
Push Fluid
Suction head is a condition where __________.
Surface level of source of supply is above pump centerline.
When the shaft assembly can be removed without disturbing the piping, in all cases, the casing is said to be:
Horizontally Split
The inlet pipe to a pump is usually greater in diameter than the discharge pipe. The reason for this is:
Get more fluid into the pump than can be discharged.
A shaft sleeve is used on a pump shaft to ____________.
To prevent wear on the shaft.
Mechanical Seals allow what?
Allow invisible or minimal leakage
What are the two basic classifications of pumps?
Dynamic and Positive Displacement
What is a Dynamic Pump?
A machine that moves fluid by using centrifugal force to spin it outwards.
What type of flow do Dynamic Pumps produce?
Smooth and Continuous
Do Dynamic Pumps convey large volumes or small volumes?
Large Volumes
What is another name for Dynamic Pumps?
Centrifugal Pumps or Non-positive Displacement Pumps
What do centrifugal pumps allow water to do which dictates it be called a Non-positive Displacement Pump.
The water can slip after the required pressure is built up.
How is slip created in a Dynamic Pump?
Created when the impellers centifugal force is the same as the resistance to in the discharge pipe.
What are the four categories of centrifugal pumps based on?
Different types of flow; Axial, mixed, radial, and peripheral.
What is Pump Head?
The pressure that a pump has to overcome to be able to move liquid through the system.
What are the three units which express pressure?
- PSI
- kPa (Kilopascals)
- Bars
What is Static Suction Lift?
The vertical distance from the liquid supply level to the pump centre line when the liquid supply level is below the pump centre line.
What is Static Suction Head?
The vertical distance from the liquid supply level to the pump centre line when the liquid supply level is above the pump centre line.
What is Static Discharge Head?
The vertical distance from the pump centre line to either the surface of the liquid in the discharge tank or to the point of discharge.
What is Total Static Head?
The vertical distance from the liquid supply level to the surface of the liquid in the discharge tank or to the point of discharge.
What is Frictional Loss?
The pressure needed by the fluid to overcome friction as it moves through the piping, valves and fittings in the system.
What is Velocity Head?
The force causing the fluid to flow through a chamber which is due to the velocity of the fluid.
What is Dynamic Suction Lift?
This is equivalent to the static suction lift plus the velocity head minus all the frictional losses in the suction pipes and fittings.
What is Dynamic Suction Head?
This is equivalent to the static suction head minus the velocity head and all the frictional losses in the suction pipes and fittings.
What is Dynamic Discharge Head?
This is the equivalent to the static discharge head plus the velocity head and all the frictional losses in the discharge pipes and fittings.
What is Vapour Binding?
When pressure on the suction side of a pump drops below the vapour pressure of the liquid, vapour forms. This can partially of completely stop the flow. This is said to be Vapour Bound.
What is Vapour Binding caused by?
Because of insificient suction head, high suction lift, excessive friction head, or high liquid temperature.
What does NPSH stand for?
Net Positive Suction Head
What is NPSH?
The required pressure at pump suction to prevent Vapour Binding and Cavitation.
What must the pressure be greater than at the pump suction?
Vapour Pressure of the pump liquid.
What is a pumps capacity determined by?
The volume of liquid delivered per unit of time.
Slip Factor is expressed as what?
A percentage.
What is Slip Factor?
The difference between the actual volume of liquid discharged by a pump and its theoretical capacity.
How are pumps rated?
They are rated according to capacity at a given head and speed.
How is a pump size expressed?
By its diameter of discharge nozzle, suction nozzle, and impeller.
Is a Volute Pump a Radial or Axial pump?
Radial Pump
What are diffusers?
Stationary, curved vanes in the casing which redirect the the flow of liquid. Used to create multiple volutes.
Are there such pumps as Axial Dynamic Pumps?
Yes. Axial Flow Pumps
What is a multi-stage pump?
What do they create more of?
- A pump with a series of impellers.
- Discharge Pressures
What kind of pump is a Regenerative Turbine Pump?
Dynamic Peripheral Pump
How many rows of vanes does a Regenerative Turbine Pump have?
2 in a single impeller.
Which has a larger discharge pressure? A radial pump or regenerative turbine pump?
Regenerative Turbine Pump because of its unique impeller flow.
Name all the different types of impellers.
Open impeller
Semi-open, single inlet impeller
Closed, single inlet impeller
Closed double-inelt impeller
Screw-style impeller
Axial-flow
Open mixed flow impeller
What general type of impeller is this?
Open Impeller
What general type of impeller is this?
Closed Impeller
What type of impeller is this?
Semi-open impeller
How many shrouds does a Semi-open Impeller have?
- Closed Impeller has two.
Which closed pump impeller has axial thrust?
Why?
Closed Single-Inlet Impeller. There is only one inlet on one side.
What are Screw Style Impellers used with?
Suspended solids
What is this?
What is this used with?
Inlets
Closed Double Inlet Impeller.
What are two ways of mounting an Impeller?
On the end of a shaft or mid-shaft.
At what point does the impeller and casing leakage become too much to be efficitent?
When the gap exceeds three times the intial clearance.
What are wear rings in a centrifugal pump?
Replaceable strips on the end of impellers and on the casing
What type of impeller wear ring format is this?
Labyrinth
What three methods are wear rings held in place?
Shrink Fit
Spigot, groove or pins
Screw Threads
What devices compensate for Axial Thrust?
Balancing Holes
Balancing Drum
Balancing Disk
What balancing device is used on single stage pumps?
Balancing Holes
What is this?
Label it.
Balancing Drum
What is this?
Label this.
Balancing Holes
What is this?
Label it.
Balancing Disk
What is this?
Balancing Drum and Disk Combination
Where are Compression packing and Mechanical Seals assembled?
Into the stuffing box.
What is the stuffing box?
A recess in the casing around the rotating shaft of the pump.
What do compression packing and mechanical seals do?
Seal between a moving shaft and casing.
Where/when are Mechanical seals used?
Used when leakage is unwanted. Or where compression packing will not work.
Is compression packing used in high or low pressure conditions?
Low pressure conditions
What is this?
Label it.
Stuffing box with four rings of packing and a lantern ring.
What is another name for a Lantern Ring?
Seal Cage
What does the Lantern Ring do?
For negative pressure pumps air can be sucked in. Packing that is lubricated prevents this. The lantern ring provides a path to lubricate the packing.
What happens if packing is not lubricated on a negative sealed pump.
Aeration. Pump will suck air in.
What are wear sleeves made from?
Stellite, Stainless Steel, Chrome, Brass and Bronze.
What kind of oil feed do Horizontal pumps have for bearings?
Drip-feed or endless chain or ring riding
What is a negative quality of Base Mounting Pumps?
If operation temperature changes the pump can become misaligned.
Do Center-line Mounted Pump have alignment issues if the operating temperature changes?
No, there is very little effect.
What is a Close-coupled Mounted Pump set up?
The motors shaft extends through the pump casing.
Do centrifugal pumps need to be primed?
Yes
What is a crutal step before starting a centrifugal pump other then priming?
All air from the seal housing is vented.
What type of drawing is this?
Sectional or Cutaway
Where are Positive Displacement Pumps used?
Where constant flow or a measured amount of flow is critical.
What is the difference between a piston pump and plunger pump?
- Plunger pumps have their plunger sliding inside the packing.
- Piston pumps have their packing sliding with their piston.
What type of pump is this?
Single-acting plunger pump
Where are Plunger Pumps usually found?
Where measured amounts of liquid is to be expelled.
How are Plunger Pumps sealed?
V, U ring packing
How are Piston Pumps sealed?
Two Ways:
- With a series of cast iron rings which are fitted into grooves in the perimeter of the piston
- With cup or U-ring packing material held in poisiton be retainers
What is this?
Diaphragm Pump
How are the intake valves and out valves operated for reciperating pumps?
The valves are check valves and they are operated by difference in pressure.
Name four types of check valves.
Flap Check Valve
Wing-guided Check Valve
Stem-guided Check Valve
Ball Check Valve
What type of check valve is this?
Stem-guided Check Valve
What type of Check Valve is this?
Wing-guided Check Valve
What type of check valve is this?
Flap Check Valve
What are Stem-guided Check Valves used for in recipracating pumps?
Low Pressure applications.
What are Wing-guided Check Valves used for in reicprocating pumps?
Moderate to High Pressure applications.
What are Flap Chack Valves used for reciprocating?
Low Pressure and Free Flow of Semi-solids.
Primarly found in diaphragm pumps.
What are Ball Check Valves used for in reciprocating pumps?
Where free opening of suction and discharge is needed.
What kinda of delivery do Rotary pumps have when it comes to volume?
Can be fixed or variable.
For Rotary Pumps which types of pumps are capable of variable delivery?
Vane and piston pumps
What type of pump is this?
Label it.
External Gear Pump
What is this?
Label it.
Internal Gear Pump
Why are Internal Gear Pumps called Internal Gear?
Because there is a gear inside which is cut with internal gears.
What is this?
Is it balanced or unbalanced?
Label it.
- Sliding Vane Pump
- Unbalance Type
What does balanced and unbalanced mean for vane pumps?
- If the pump is balanced the rotor is in the center of the elliptical case and the pump has two outlets and two inlets to balance forces.
- Unbalanced mean the pump is offset in the elliptical case and force builds on one side of the rotor.
What is this?
Label it.
Balanced Vane Pump
What kind of pump is this?
Variable Vane Pump
What is able to be moved in a Variable Vane Pump?
Pressure-Chamber Ring
What is this?
Label it.
External Vane Pump
How many Sliding Vanes does an External Vane Pump have?
One Sliding Vane
What shape of Rotor does an External Vane Pump have?
Oval
What is another name for Peristaltic Pumps?
Flexible Tube Pumps
Where are Flexible Tube Pumps used?
What kind pressure and rpm can it handle.
- In proccess’s requiring measured flow for slurry, sludge, pulp and unusual material.
- Low. 200 rpm and 100 psi
What is this?
Flexible Tube Pump
What is this?
What kind of Rotor does this use?
What shape is the Rotor?
- Flexible Liner Pump
- Eccentric
- Circle
What is this?
Flexible Vane Pump
Name 3 type of Flexible Pumps
Flexible Vane Pump
Flexible Tube Pump
Flexible Liner Pump
What compresses the fluid in a Flexible Vane Pump?
The insert which takes up space.
What rpm does the Flexible Vane Pump run at?
Moderate (6000 rpm)
What synchronizes the lobes in a Lobe Pump?
The external timing gears.
What type of Lobe is this?
Single Lobe
What is a stator?
The stationary lobed casing which meshes with a screw in a screw pump.
What is another name for a Single Screw Pump?
Progressive Cavity Pump
What is this?
Label it.
Single Screw Pump
What is this?
A Three-lobe Pump
What is this?
Label it.
Axial Piston Pump
What is this?
Radial Piston Pump
Is the shaft of a Radial Piston Pump Eccentric or Ellipical?
Eccentric
- How are Positive Displacement Pumps capcities regulated usually?
- Do pressure variations affect output?
- By varying speed.
- Only slightly
Without a Pressure Relief Valve what could happen to the positive displacement pump?
Line could get blocked causing pump to break or motor stall out
What does Bidirectional mean for pumps?
They can moving in both directions.
What is an important check to ensure the hydraulic system is running to design.
Running speed of pump.
A varibale displacement pump does not require a seperate relief valve becuase the pump can what?
Shift to a no flow position.
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B) Impeller Eye blocked
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