Pumps

PUMPS · · ·

Balane Leron Marcaida Peñalosa BSME 5B – (GROUP 3)

Table of Contents DEFINITION & PARTS TYPES PROBLEMS ENCOUNTERED DURING OPERATION AND ITS SOLUTIONS 2

1 DEFINITION & PARTS Pumps

What is a pump? ●

A pump is a mechanical device used to force a fluid (a liquid or a gas) to move forward inside a pipeline or hose. They are also used to produce pressure by the creation of a suction (partial vacuum), which causes the fluid to rise to a higher altitude. 4

What is a pump? ●

Pumps operate by some mechanism (typically reciprocating or rotary), and consume energy to perform mechanical work moving the fluid. 5

“

Mechanical pumps serve in a wide range of applications such as pumping water from wells, aquarium filtering, pond filtering and aeration, in the car industry for watercooling and fuel injection, in the energy industry for pumping oil and natural gas or for operating cooling towers. 6

Water Pump

7

What is the difference between a pump and a compressor? ●

Compressors operate on compressible fluids, typically gases. Pumps operate on fluids, typically liquids, approximated as incompressible. 8

What is the difference between a pump and a compressor? ●

Compressors are intended to develop a very high pressure rise against a closed system; pumps are designed to develop relatively little pressure against a free-flowing system with minimal back-pressure. 9

What is the difference between a pump and a compressor? ●

Pumps are often used in continuous-flow operation, while many lower-end compressors must have intermittent duty cycles. 10

What is the difference between a pump and a compressor? ●

Compressors usually have a feedback sensor to shut off when they reach a desired pressure; pumps have a fixed design and operate freely across their performance curve as conditions change 11

Parts of a pump • • • • •

Housing/casing Impeller Motor Shaft Volute 12

Housing/casing The outer shell of the pump which protects most of the components from the outside elements. The casing of the pump should be of materials suitable to withstand the environ– mental conditions of the application (e.g. submersible pumps should be water and rust corrosion resistant. ●

13

Pump Housing

14

Impeller A rotating disk with a set of vanes coupled to a shaft. When the impeller rotates, it imparts energy to the fluid to induce flow. Flow characteristics of the pump vary widely based on the impeller design. ●

15

Pump Impeller

16

Motor The power source of the pump which drives the shaft. AC motors and DC motors are the most common power sources for pumps, but internal combustion engines (ICEs), hydraulic power, and steam power are other possibilities. ●

17

Pump Motor

18

Shaft The shaft connects the impeller to the motor/engine that provides power for the pump. ●

19

Pump Shaft

20

Volute The inner casing that contains the impeller and collects, discharges, and (sometimes) recirculates the fluid being pumped. The materials used to construct the lining of the pump volute must be compatible with the handled media. ●

21

Pump Volute

22

Other components ● ●

●

Bearing Assembly Hub Seal

23

Bearing assembly The mechanical support that allows continuous rotation of the impeller and is continuously lubricated. ●

24

Hub Device attached to the bearing assembly which is the connecting point for the motor or engine. ●

25

Seal Protects the bearing assembly from being contaminated by the pumped media. ●

26

2 TYPES Pumps

Major types of pumps

1 Dynamic Pumps

&

2 Positive Displacement Pumps 28

DYNAMIC PUMPS 29

What is a Dynamic Pump? ●

Dynamic pumps impart velocity and pressure to the fluid as it moves past or through the pump impeller and, subsequently, convert some of that velocity into additional pressure. It is also called Kinetic pumps. 30

“

Dynamic pumps are subdivided into two major groups and they are centrifugal pumps and vertical pumps. 31

DYNAMIC PUMPS CENTRIFUGAL PUMPS *Based on major direction of flow

Radial Flow

Axial Flow

VERTICAL PUMPS Line Shaft Pumps Submersible Pumps

Mixed Flow 32

Dynamic pumps CENTRIFUGAL PUMPS A centrifugal pump is a rotating machine in which flow and pressure are generated dynamically. The energy changes occur by virtue of two main parts of the pump, the impeller and the volute or casing.

VERTICAL PUMPS Vertical pumps were originally developed for well pumping. The bore size of the well limits the outside diameter of the pump and so controls the overall pump design. 33

Centrifugal

Pump

Vertical

Pump

DYNAMIC PUMPS CENTRIFUGAL PUMPS *Based on major direction of flow

Radial Flow

Axial Flow

VERTICAL PUMPS Line Shaft Pumps Submersible Pumps

Mixed Flow 35

Types of Centrifugal Pump (Based on major direction of flow)

Radial flow Axial flow Mixed flow 36

Radial flow ●The impeller discharges fluid at right angles to the shaft axis. ●The radial type pumps are used for the application of high head and low discharge.

Axial flow

Mixed flow

●The flow ●The flow direction through impeller is is partly axial and parallel to shaft partly radial. Hence axis low head and has a result the flow very high is diagonal. discharge. ●The mixed flow type ●The axial flow type pumps are used for pumps are used for the application of the application of medium head and medium head and high discharge. high discharge. 37

Radial

flow

Mixed Axial

flow

flow

DYNAMIC PUMPS CENTRIFUGAL PUMPS *Based on major direction of flow

Radial Flow

Axial Flow

VERTICAL PUMPS Line Shaft Pumps Submersible Pumps

Mixed Flow 39

Types of Vertical Pump Line-shaft pumps Submersible Pumps 40

Vertical pumps LINE-SHAFT PUMPS The driver is mounted on the discharge head for these type of motors. The lineshafting extend through the column to the bowl assembly and transmits torque to the pump rotor.

SUBMERSIBLE PUMPS Submersible pumps are close-coupled pumps driven by a submersible motor and designed for submerged installation in a wet well. The motor is mounted below the bowl assembly and is directly coupled to the pump rotor shaft. 41

Line-Shaft

Pump

Submersible

Pump

POSITIVE DISPLACEMENT PUMPS 43

What is a Positive Displacement Pump? ● Positive displacement pumps, the moving element (piston, plunger, rotor, lobe, or gear) displaces the liquid from the pump casing (or cylinder) and, at the same time, raises the pressure of the liquid. So it does not develop pressure; it only produces a flow of fluid. 44

“

Positive displacement pumps are subdivided into three major groups and they are rotary type pumps, reciprocating pumps and pneumatic pumps. 45

POSITIVE DISPLACEMENT PUMPS ROTARY TYPE PUMPS

RECIPROCATING PUMPS

Rotary Lobe Pumps

Diaphragm pumps

Screw Pumps

Plunger / piston type pumps

Progressive Cavity Pumps

PNEUMATIC PUMPS 46

Rotary type pumps ●The pump rotor of rotary pumps displaces the liquid either by rotating or by a rotating and orbiting motion. ●The rotary pump mechanisms consisting of a casing with closely fitted cams, lobes, or vanes, that provide a means for conveying a fluid. 47

Rotary lobe Screw pumps ● Screw pumps are pumps ● Lobe pumps contains two elastomer-coated rotors that are driven by an integral gear box and synchronized by timing gears.

high-volume, nonclog, atmospheric head devices that can pump a variety of solids and debris in raw waste water without screening. Screw pumps, however, have a practical limitation as to pumping head.

Progressive Cavity pumps ● A progressive cavity pump is designed specifically to transfer abrasive and viscous fluids with a high solid, fiber, and air content. A hard steel screw rotor rotates and orbits within an elastomer stator. 48

Rotary Lobe

Screw

Pump

Pump

Progressive Cavity

Pump

POSITIVE DISPLACEMENT PUMPS ROTARY TYPE PUMPS

RECIPROCATING PUMPS

Rotary Lobe Pumps

Diaphragm pumps

Screw Pumps

Plunger / piston type pumps

Progressive Cavity Pumps

PNEUMATIC PUMPS 50

Reciprocating pumps ●In a reciprocating pump, a piston or plunger moves up and down. ●During the suction stroke, the pump cylinder fills with fresh liquid, and the discharge stroke displaces it through a check valve into the discharge line. 51

Reciprocating pumps PLUNGER TYPE PUMPS The plunger contains the cross head, driven by a cams haft arrangement. The capacity of the pump can be adjusted by changing the stroke, the rotating speed of the pump, or both. The stroke of the pump is changed by the eccentric pin setting. Such pumps are available in singleand multi cylinder models.

DIAPHRAGM PUMPS These type of pumps are quite versatile, handling a wide variety of fluids like food additives, chemicals, dry powders, slurries, and wastewater. The advantages in diaphragm pumps is the absence of seals or packing, meaning they can be used in applications requiring zero leakage. 52

Diaphragm

Pump

Plunger Type

Pump

POSITIVE DISPLACEMENT PUMPS ROTARY TYPE PUMPS

RECIPROCATING PUMPS

Rotary Lobe Pumps

Diaphragm pumps

Screw Pumps

Plunger/piston type pumps

Progressive Cavity Pumps

PNEUMATIC PUMPS 54

Pneumatic pumps ●Compressed air is used to move the liquid in pneumatic pumps. ●In pneumatic ejectors, compressed air displaces the liquid from a gravity-fed pressure vessel through a check valve into the discharge line in a series of surges spaced by the time required for the tank or receiver to fill again. 55

Pneumatic

Pump

3 PROBLEMS ENCOUNTERED & SOLUTIONS Pumps

5 Common Problems Found in Pumps ● While handling pumps, you do not need to be an expert. All you need to know is how to identify some basic signs and preventive actions which are to be taken whenever required. 58

5 Common Problems • No liquid delivery • Not enough liquid delivered • Not enough pressure • Pump operates for short time, then stops • Pump takes too much power

1. No liquid delivery Causes

Solutions

Lack of prime

Fill pump and suction pipe completely with liquid.

Loss of prime

Check for leaks in suction pipe joints and fittings; vent casing to remove accumulated air. 60

1. No liquid delivery Causes Suction lift too high

Solutions If no obstruction at inlet, check for pipe friction losses. Measure with mercury column or vacuum gauge while pump operates. If static lift is too high, liquid to be pumped must be raised or pump lowered. 61

1. No liquid delivery Causes Impeller is plugged

Solutions Dismantle pump or use piping hand hole to clean impeller.

Check whether motor is directly across-the-line and receiving full Speed too low voltage. Alternatively, frequency may be too low; motor may have an open phase. 62

1. No liquid delivery Causes Discharge system head too high Wrong direction of rotation

Solutions Check pipe friction losses. Larger discharge piping may correct condition. Check that valves are wide open. Check motor rotation with directional arrow on pump casing. Wrong rotation will cause pump damage. 63

2. Not enough liquid delivered Causes Air leaks in suction piping

Solutions If liquid pumped is water or other nonexplosive, and explosive gas or dust is not present, test flanges for leakage with flame or match. For such liquids as gasoline, suction line can be tested by shutting off or plugging inlet and putting line under pressure. A gauge will indicate a leak with a drop of pressure. 64

2. Not enough liquid delivered Causes

Solutions

Speed too low

Check whether motor is directly across-the-line and receiving full voltage.

Air leaks in stuffing box

Increase seal lubricant pressure to above atmosphere. 65

2. Not enough liquid delivered Causes

Solutions

Discharge system head too high

Check pipe friction losses. Larger discharge piping may correct condition.

Suction lift too high

If no obstruction at inlet, check for pipe friction losses. Measure with mercury column or vacuum gauge while pump operates. 66

2. Not enough liquid delivered Causes

Solutions

Impeller diameter too small

Check with factory to see if a larger impeller can be used; or cut pipe losses or increase speed, or both, as needed.

Impeller partially plugged

Dismantle pump or use piping hand hole to clean impeller. 67

2. Not enough liquid delivered Causes

Solutions

Defective impeller

Inspect impeller. Replace if damaged or vane sections badly eroded. Compare rotation of motor with directional arrow on pump casing. Wrong rotation will cause pump damage.

Wrong direction of rotation

68

3. Not enough pressure Causes Air leaks in suction piping

Solutions If liquid pumped is water or other non-explosive, and explosive gas or dust is not present, test flanges for leakage with flame or match. For such liquids as gasoline, suction line can be tested by shutting off or plugging inlet and putting line under pressure. A gauge will indicate a leak with a drop of pressure. 69

3. Not enough pressure Causes

Solutions

Check with factory to see if a Impeller diameter larger impeller can be used; or cut pipe losses or increase speed, or too small both, as needed. But be careful not to seriously overload drive.

Excessive impeller Adjust impeller clearance. clearance 70

3. Not enough pressure Causes Speed too low

Solutions Check whether motor is directly across-the-line and receiving full voltage. Alternatively, frequency may be too low; motor may have an open phase. 71

4. Pump operates for short time, then stops Causes Suction lift too high

Solutions

If no obstruction at inlet, check for pipe friction losses. However, static lift may be too great. Measure with mercury column or vacuum gauge while pump operates. If static lift is too high, liquid to be pumped must be raised or pump lowered. 72

4. Pump operates for short time, then stops Causes Incomplete priming

Solutions Free pump, piping and valves of all air. If high points in suction line prevent this, they need correcting. Check whether motor is directly across-theline and receiving full voltage. Alternatively, frequency may be too low; motor may have an open phase. 73

5. Pump takes too much power Causes

Head lower than rating; thereby pumping too much liquid

Solutions

Machine impeller's OD to size advised by factory

Mechanical defects in turbine, If trouble cannot be engine, or other type of drive located, consult factory. exclusive of motor 74

5. Pump takes too much power

Causes

Cavitation

Solutions

a. Increase positive suction head on pump by lowering pump or increasing suction pipe size or raising fluid level. b. Sub-cool suction piping at inlet to lower entering liquid temperature. c. Pressurize suction vessel. 75

5. Pump takes too much power

Causes

Solutions

Misalignment

Realign pump and driver.

Casing distorted by excessive strains from suction or discharge piping

Check alignment. Examine pump for friction between impeller and casing. Replace damaged parts. Check for pipe strain. 76

End of Report 77