Watson McDaniel Steam Design Guide

Steam & Condensate Introduction

Steam Traps

Typical equipment used for process heating in steam systems A steam jacketed kettle contains a liquid to be heated surrounded by an isolated jacket containing the steam (steam does not contact the fluid). They are typically found in commercial food processing facilities. The Shell & Tube Heat Exchanger is used for continuous processes where a liquid to be heated (such as water), continually flows through the tubes surrounded by the steam.

Steam Jacketed Kettle

Shell & Tube Heat Exchanger (Single tube shown for clarity)

Pressurized Steam enters

Steam is contained in a “jacket” which surrounds the Kettle and heats the contents indirectly through the metal wall

Shell contains the steam which surrounds the tube section in order to heat the liquid flowing thru it

Pressurized Steam enters

Liquid to be heated

Hot Water Exits

Single Tube shown for clarity

Cold liquid enters the tube section & the heated liquid exits

Cold Water Enters

Condensate discharges from below

Condensate discharges from below

Typical pieces of equipment used to control, protect and optimize steam systems Now that a basic understanding of steam has been provided, let’s introduce some components of the system and their general purposes:

Steam Traps

Since steam is created from water, it will condense back to water after releasing its energy during heating. This water, or condensate, must be removed to not only ensure proper heat transfer, but system safety as well. Removing condensate without the loss of live steam is the primary function of Steam Traps. Steam traps also discharge air that is present in the system prior to system start-up.

Pressure Regulators & Control Valves

Steam is generated at the boiler at pressures sufficient to ensure travel throughout the entire piping system. Pressure Regulating Valves and Control Valves may be used for temperature control or to reduce the steam pressure generated at the boiler down to more usable levels.

Condensate Return Pumps

When condensate does not have sufficient pressure to return to the boiler on its own, mechanical or electric pumps are required to pump the condensate back to the boiler.

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