PUMPS (CENTRIFUGAL & PD), VALVES & ITS TYPES, USES IN INDUSTRY, TURBOMACHINERY

1. Fluid Mechanics
Credit Hours 2(2+0)

2. 2
Books Recommended
 Holland, F. A. Bragg, R. “Fluid flow for Chemical Engineers”,
2nd Edition, Butterworth & Heinemann. 1995.
 White, F. M. “Fluid Mechanics”, 4th Edition, McGraw-Hill.
1999.
 Noel-de-Nevers “Fluid Mechanics for Chemical Engineers”
McGraw-Hill
 McCabe Warren L., Smith Julian C., Harriott peter “Unit
Operations of chemical Engineering” 6thEd. 2001. McGraw-
Hill Inc.
 Coulson J. M., Richardson J. F. “Chemical Engineering” Vol-I,
1999. Butterworth, Elsevier.
 Fundamentals of Fluid Mechanics, 6th Edition.

3. 3
What We Will Study
 Concept of centrifugal pumps; Centrifugal
pump characteristics; NPSH and its application
in chemical engineering; concept of specific
speed; similarity laws in centrifugal pumps;
pumps in series and parallel; Positive
displacement pumps, their classification,
characteristics and selection; matching system
characteristics with pump characteristics.
 Turbo-machinery and its classifications.

4. 4
 Compressors, their classification,
characteristics and selection. Turbines, their
classification and selection. Compressible flow
and its application in chemical engineering,
concept of choked flow. Flow through porous
media; Fluidization and types of fluidized beds
and their use in chemical engineering, concept
of hydrodynamic characteristics of fluidized
beds. Introduction to non-Newtonian fluids
 Concept of various types of valves and their
principles.

5. Pipe Sizes
Schedule Number
The wall thickness of a pipe is denoted by schedule number. As the
schedule number increases the thickness of pipe also increases
(10,20,30.....120,160).
Nominal Diameter
It is not inner diameter or outer diameter, It is just a diameter of pipe,
which is near to inner or outer diameter of pipe.
Tube Sizes
The size of tubing is indicated by the outside diameter. Wall
thickness is ordinarily given by the (BWG) Birmingham wire gauge
number, Range 07-24.
At 07 max thickness of tube/sheet.
At 24 min thickness of tube/sheet.

6. Standard cubic Feet of a Gas
Gas equipment is ordinary rated in terms of standard cubic feet of
gas.
A volume is standard cubic feet, which is measured at specified
temperature and pressure regardless of the actual temperature &
pressure. Various standards are used e.g.
P = 29.92 inch Hg
T= 32 F
St. ft3
of gas = 359 ft3
/lb mole of gas.
P = 30 inch Hg
T= 60 F
St. ft3
of gas = 378.8 ft3
/lb mole of gas.

8. Types of Valves
1. Globe valve.
2. Gate valve.
3. Diaphragm valve.
4. Butterfly valve.
5. Ball valve.
6. Check valve.
7. Needle valve.
8. Safety valve.
9. Breathing valve.
10. And so on...

10. Gate Valve
Uses of Gate Valve
 Stop valve.
 Fully open or fully closed.
 Not normally consider for throttling purpose.
 Suitable for high pressure and high temperature.
 Not usually used for slurries and viscous fluids.
Advantages
 Low pressure drop.
 Provides tight seal when fully closed.
 Relatively free of contamination build up.
Disadvantages
 Vibration when in partially open.
 Seat & disc wears when used for throttling purpose.
 Large size gate valves not recommended for steam service.
 Required large actuation forces.

11. 11
Typical Usage of Gate Valve
 Block valve for control valve
 Pump suction valve
 Pump discharge valve
 Block valve for level controller & level gauge
 Drain valve of equipment
 Drain valve of process & utility line
 First block valve of sampling nozzle
 Block valve for safety valve
 Block valve for equipment
 Block valve for steam trap
 By-pass valve for emergency shut-down valve
 Flow control valve for large size gas & city water line

12. GLOBE VALVE
 INTRODUCTION
Globe valves are named for their spherical body shape.
The two halves of the valve body are separated by a
baffle with a disc in the center. Globe valves operate by
screw action of the handwheel. They are used for
applications requiring throttling and frequent operation.
Since the baffle restricts flow, they're not recommended
where full, unobstructed flow is required.

14. Globe Valve
Uses of Globe Valve
 Flow regulation.
 Normally consider for throttling purpose.
Advantages
 High pressure drop.
 Good shutoff capability
 Reasonably good throttling capability
Disadvantages
 Costly as compared to gate valves.
 Required large actuation forces.

15. USAGE OF GLOBE VALVE TYPICAL
 Manual flow control valve
 By-pass valve for control valve
 Hose connection
 Vent valve of equipment and piping
 Minimum flow line for pump
 Pressure gauge outlet
 By-pass line of reciprocating compressor

16. Comparison between Gate valve and Globe Valve
 Gate valves are used for On-Off control whereas Globe valves
in addition can also be used for the flow regulation.
 Gate valves offer very little resistance to fluid flow in fully open
position and also have small pressure drop across the valve.
Globe valves on the other hand have a high pressure drop
even in fully open conditions and offer substantial resistance to
fluid flow.
 Gate valves of the same size are cheaper than globe valves.
 Gate valves because of their design have very little fluid
trapping in the line but the globe valves have a larger amount
due to the direction of flow.
 Gate valves are unidirectional and can be put around in any
way. The globe valves are not.

17. VALVE OPERATING DEVICES
 Manual
 Hand wheel or lever is directly connected to the stem and is
operated by hand
 Hydraulic
 Hydraulic pressure is applied to one side of a piston which is
connected to the stem of the valve
 Motor
 A hydraulic, electric, or air driven motor is used to turn the stem of
the valve
 Solenoid
 Uses an electromagnet to open or close a valve against spring
pressure

18. SELECTION OF VALVE
 Identify application characteristics
 Select type of valve required
 Select valve size
 Select valve end connection
 Select valve body, bonnet and trim materials
 Identify seat-leakage criteria
 Identify requirements for valve-stem packing
arrangement
 Be-aware of piping layout and valve orientation
 Taken into consideration maintenance requirements
 Initial cost

19. Ball valves
Session 2 - Fall 2015 19
• They have a ball-shaped , movable flow control
element in the center of the valve
• They don’t lift the flow control device out of the
process stream. Instead, the hollow ball rotates into
the open or closed position
• Provide very little restriction to flow and can be fully
opened with a quarter turn on the valve handle
• They do not generally seal as well as globe valves
in high pressure service.
• They require a quarter turn on the valve handle to
be totally opened.

20. Ball Valve Components

21. Ball Valve

22. Pinch Valves
Uses of Pinch Valves
 Systems carrying slurries, gels etc.
Advantages
 Low in cost.
 Insensitive to contamination.
 Have low pressure drop
 Tightly closed.
Disadvantages
 Flexible membrane in pinch valves are subjected to wear & hence
periodic replacement is required.
 Generally limited to low pressure.
 Low temperature applications.
 Generally required high actuation forces to close off.

23. Diaphragm Valves
Uses of Diaphragm Valves
 Used for sealing purposes
 Suitable for abrasive as well as clean fluids.
Advantages
 Offers min resistance to flow in open position.
 Due to low pressure drop of diaphragm valve
no stuffing box required.
 Any sort of blockage can be cleaned.
 Well suited to service where tight, accurate
closure is important.
 Diaphragm can be replaced with out removing the body.
Disadvantages
 Temperature and pressure are limited.
 Limited to pressure of 50 psi.

24. 24
Diaphragm Valve Components

25. Application of Diaphragm valve in Industries
 Fertilizer Plants
 Water Treatment Plant
 Waste Water Treatment Plant
 Rayon Plant
 Petrochemical Industries
 Food Industries
 Pharmaceuticals Industries
 Sugar Plants
 Chemical Industries
 Thermal Power Stations
 Other Process Industries

26. Relief valves
• Respond automatically to sudden increases of
pressure in liquid services
• A disc is held in place by a spring that doesn’t open
until the system pressure exceeds operating limits
• They are designed to open slowly
• For pressurized liquid service and not gases
• The spring tension is adjustable
26

27. 27
Relief Valve Components

28. Safety valves
• Respond to excess vapor, or gas, pressures
• The excess pressure is vented to the flare header or
to the atmosphere
• Very similar to a relief valve
• Relief valves are designed to lift slowly
• Safety valves can exhaust more larger flow of gases
at lower velocities
28

29. 29
Safety Valve Components

30. 30
Safety Valve

31. Safety Valves
Poppet Valves
Uses
 Pressure control.
 Check.
 Safety.
 Relief function.
Advantages
 Provides large flow with very little actuator travel.
 Excellent leakage control.
 Low pressure drop.
Disadvantages
 Subject to pressure imbalances which may cause problems in some
applications.
 Seating surfaces may be subject to contamination.

32. Check valves
• It prevents reverse flow to protect the equipment
from contamination or damaging
• A swing check includes a hinged disc that slams
shut when flow reverse
• Flow keeps the disc open while flowing
32

33. 33
Swing Check Valve

34. 34
 A lift check has a disc that rests on the seat when
flow is idle and lift with flow
 Lift checks are ideal for systems in which flow rates
fluctuates
 A ball check design, has a ball shaped disc on a
round seat
 It is good when flow rates fluctuate or the fluid
contains some solids
 The ball and lift checks are more durable than the
swing check

35. 35
Lift Check Valve

36. 36
Ball Check Valve

37.  A stop check valve has characteristics of a lift check
and a globe valve
 In the closed position, the stop check disc is firmly
seated
 In the open position, the stem rises out of the body
of the flow control element and acts as a guide for
the disc
 The degree of the lift can be controlled
37

38. Butterfly valves
 Are commonly used for both throttling and on/off
service
 Its body is relatively small
 The flow control element is a disc
 A metal shaft extends through the center of the disc
and allows it to rotate one quarter
 Butterfly valves are designed to be operated at low
temperature and low pressure.
38

39. 39
Butterfly Valve Components

40. 40
Butterfly Valve

41. Plug valves
• A quick opening, one-quarter turn plug valves are
very popular in the process industry
• The flow control element has a plug shape
• Provide very little restriction to flow
• Can be opened 100% with a one quarter turn on the
valve handle
• Temperatures lower than 480 ºF
41

42. 42
Plug Valve Components

43. 43
Plug Valve

44. 44
Control valves/Automatic valves
44
• Sensing, indicating, transmitting,
comparing, and/or controlling.
• The final element in a control loop
is a control valve
• Can be air operated, electrically
operated , or hydraulically
operated

45. 45
Pneumatic Automatic Valve

46. 46
Pneumatic Automatic Valve Components

47. 47
Solenoid Valve

49. Direct Acting & Reverse Acting Valves

50. 50
Valve Symbols