Feed Pumps in Steam Systems - Suction Lift Head vs. Temperature
Cavitation of impellers increases with water temperatures.
To avoid cavitation in a feed pump the suction lift and pressure head should not exceed the limits indicated below:
Temperature of Feeding Water | Max Suction Lift | Minimum Pressure Head | |||
---|---|---|---|---|---|
(oC) | (oF) | (m) | (ft) | (m) | (ft) |
55 | 130 | 3 | 10 | ||
65 | 150 | 2 | 7 | ||
77 | 170 | 0.6 | 2 | ||
80 | 175 | 0 | 0 | 0 | 0 |
87 | 190 | 1.5 | 5 | ||
95 | 200 | 3.5 | 10 | ||
99 | 210 | 4.5 | 15 | ||
100 | 212 | 5 | 17 |
For water with temperature above 80 oC (175 oF) it is necessary with a positive pressure head - and the pump is located in an elevation below the water or condensate receiver.
In steam distribution systems its common with open vented condensate receivers with temperatures close to 100 oC (212 oF). This is true especially in systems where most of the steam consumed is returned as hot condensate, but also in systems where the make up water is heated to reduce the amount of air dissolved in the water.
- Recommended Suction Flow Velocity for Boiling Fluids - Recommended flow velocity for the pump suction side.
- Recommended Delivery Flow Velocity for Boiling Liquids - Flow velocity normally required on the delivery side of the pump in systems with boiling liquids.
- 1 ft (foot) = 0.3048 m
Related Topics
-
Sizing of Steam and Condensate Pipes
Dimensions of steam and condensate pipe lines. Calculate pressure losses, recommended velocities, capacities and more. -
Steam and Condensate
Design of steam & condensate systems with properties, capacities, sizing of pipe lines, system configuration and more.
Related Documents
-
ASME - International Boiler and Pressure Vessel Code
The International Boiler and Pressure Vessel Code safety rules governing design, fabrication, and inspection of boilers and pressure vessels, and nuclear power plant components during construction. -
Boiler Blowdown Rate
Calculate boiler blowdown rate. -
Boiler Feed Water - Chemistry and Impurity Limits
ABMA recommended feed water chemistry limits for steam boilers. -
Boiling Fluids - Max Suction Flow Velocities
Recommended max suction flow velocity when pumping boiling fluids. -
Boiling Liquids - Max Pumping Flow Velocities
Recommended max flow velocity on the delivery (pressure) side when pumping boiling liquids. -
Cavitation
Cavitation occurs in fluid flow systems where the local static pressures are below the fluids vapor pressure. -
Feed Water Treatment to Avoid Corrosion
Make-up water to steam boilers should be treated with oxygen scavengers to avoid serious corrosion problems. -
Flash Steam Generation - Fundamental Physics
Tutorial to the basic physics behind flash steam generation -
Liquids and Gases - Boiling Points
Boiling temperatures for common liquids and gases - acetone, butane, propane and more. -
Recommended Velocities in Steam Systems
The steam velocity in a steam distribution system should be within certain limits to avoid excessive wear and tear -
Water - Boiling Points at Higher Pressures
Online calculator, figures and tables showing boiling points of water at pressures ranging from 14.7 to 3200 psia (1 to 220 bara). Temperature given as °C, °F, K and °R. -
Water - Boiling Points at Vacuum Pressure
Online calculator, figures and tables giving the boiling temperatures of water in varying vacuum, SI and Imperial units. -
Water - Boiling Points vs. Altitude
Elevation above sea level and the boiling point of water.