Part 2: What Steam Is, How Steam is Used, and the Properties of Steam

Steam is the gaseous phase (state) of water and has many domestic, commercial, and industrial uses. There are two categories of steam - wet steam and dry steam. In dry steam, all the water molecules stay in the gaseous state. In wet steam, some of the water molecules have released their energy (latent heat) and begin condensing into water droplets.

Steam, usually created by a boiler burning coal or other fuels, became the primary source of energy for mechanical movement during the industrial revolution, ultimately being replaced by fossil fuels and electricity.

Steam has many commercial and industrial uses. In agricultural, steam is used to remediate and sterilize soil. In power generation, approximately 90% of our electricity is created using steam as the working fluid to spin turbines. Autoclaves use steam for sterilization in microbiology labs, research, and healthcare facilities. Many commercial and industrial pieces of equipment are cleaned with steam. Finally, commercial complexes, campuses and military buildings use steam for heat and humidification.

The following video, the second part of a three part series titled “What Steam Is, How Steam is Used, and the Properties of Steam” provides the viewer with an exceptional basis to build from. Special thanks to Armstrong International who created the original work.

For more information on any industrial or commercial steam application, contact:

Mead O'Brien, Inc.

www.meadobrien.com

(800) 892-2769

Part 1: What Steam Is, How Steam is Used, and the Properties of Steam

Steam is the gaseous phase (state) of water and has many domestic, commercial, and industrial uses. There are two categories of steam - wet steam and dry steam. In dry steam, all the water molecules stay in the gaseous state. In wet steam, some of the water molecules have released their energy (latent heat) and begin condensing into water droplets.

Steam, usually created by a boiler burning coal or other fuels, became the primary source of energy for mechanical movement during the industrial revolution, ultimately being replaced by fossil fuels and electricity.

Steam has many commercial and industrial uses. In agricultural, steam is used to remediate and sterilize soil. In power generation, approximately 90% of our electricity is created using steam as the working fluid to spin turbines. Autoclaves use steam for sterilization in microbiology labs, research, and healthcare facilities. Many commercial and industrial pieces of equipment are cleaned with steam. Finally, commercial complexes, campuses and military buildings use steam for heat and humidification.

The following video, the first part of a three part series titled “What Steam Is, How Steam is Used, and the Properties of Steam” provides the viewer with an exceptional basis to build from. Special thanks to Armstrong International who created the original work.

For more information on any industrial or commercial steam application, contact:

Mead O'Brien, Inc.
www.meadobrien.com
(800) 892-2769

Steam Trap Testing Guide for Energy Conservation

Annual steam trap testing schedule

Below is a steam trap testing guide (courtesy of Armstrong International) to maximize efficiency and conserve energy. This guide discusses:

• Steam Trap Testing Procedure 
• Tips On Listening 
• Inverted Bucket 
• Float & Thermostatic Trap 
• Disc Trap 
• Thermostatic Trap 
• Sub-Cooling Trap 
• Traps on Superheated Steam

CAUTION: Valves in steam lines should be opened or closed by authorized personnel only, following the correct procedure for specific system conditions. Always isolate steam trap from pressurized supply and return lines before opening for inspection or repair. Isolate strainer from pressurized system before opening to clean. Failure to follow correct procedures can result in system damage and possible bodily injury.

Steam Trap Testing Guide for Energy Conservation from Mead O'Brien, Inc.

Closed Loop Control System Basics

Closed loop diagram

The video below explains the concept of a closed loop control system, using a steam heat exchanger and food processing application as an example.

A closed loop control system uses a sensor that feeds current system information back to a controller. That information is then compared to a reference point or desired state. Finally, a a corrective signal is sent to a control element that attempts to make the system achieve its desired state.

A very basic example of a temperature control loop includes a tank filled with product (the process variable), a thermocouple (the sensor), a thermostat (the controller), and a steam control valve feeding a tubing bundle (the final control element).

The video outlines all the major parts of the system, including the measured variable, the set point, the controlled variable, controller, error and disturbance.

Suggestions for An Efficient Industrial Steam System

(image courtesy of OSHA.gov)

Here is a video, courtesy of Armstrong International, which provides a broad overview, and suggestions for proper use, of the key components of a well designed steam system.  Covered in this video are:

• 4 basic components of a steam system
• Water-side care
• Steam mains
• Drip legs and drip traps
• Branch piping, or runouts
• Non-condensible gases
• Proper selection of trap type and size
• Thermostatic and thermodynamic traps
• Thermostatic air vents
• Vacuum breakers
• Condensate management
• Heat exchangers
• Return lines

For more information on any steam or hot water system, contact:

Mead O'Brien
(800) 892-2769
www.meadobrien.com

The Steam Table, Terms and Heat Transfer Concepts

Steam Table, courtesy of
Armstrong International
(click image for larger view)

Here are some basic steam terms associated with the Steam Table (left). Below is a slideshow of basic heat transfer concepts.

Saturated steam is pure steam at the temperature that corresponds to the boiling temperature of water at the existing pressure.

Absolute and Gauge Pressures
Absolute pressure is pressure in pounds per square inch (psia) above a perfect vacuum. Gauge pressure is pressure in pounds per square inch above atmospheric pressure, which is 14.7 pounds per square inch absolute. Gauge pressure (psig) plus 14.7 equals absolute pressure. Or, absolute pressure minus 14.7 equals gauge pressure.

Pressure/Temperature Relationship
For every pressure of pure steam there is a corresponding temperature. Example: The temperature of 250 psig pure steam is always 406°F.

Heat of Saturated Liquid
This is the amount of heat required to raise the temperature of a pound of water from 32°F to the boiling point at the pressure and temperature shown. It is expressed in British thermal units (Btu).

Latent Heat or Heat of Vaporization
The amount of heat (expressed in BTU) required to change a pound of boiling water to a pound of steam. This same amount of heat is released when a pound of steam is condensed back into a pound of water. This heat quantity is different for every pressure/temperature combination.

Total Heat of Steam
The sum of the Heat of the Liquid and Latent Heat in Btu. It is the total heat in steam above 32°F. Specific Volume of Liquid. The volume per unit of mass in cubic feet per pound.

Specific Volume of Steam
The volume per unit of mass in cubic feet per pound.

Basic Heat Transfer Concepts from Mead O'Brien, Inc.

For more information about any commercial or industrial steam or hot water systems, contact:

Mead O’Brien, Inc.

10800 Midwest Industrial Blvd

St. Louis, Missouri 63132

Phone (314) 423-5161

Toll Free (800) 874-9655

Fax (314) 423-5707

Email: sales@meadobrien.com

www.meadobrien.com

Welcome to Mead O'Brien's Steam, Valve, Process Control, and HVAC Blog

Welcome and thanks for visiting. We established this blog as a means to provide educational information in the field of steam management, industrial hot water systems, industrial valves, and process instruments.

Our weekly posts will attempt to teach the reader something new and interesting in the field of industrial control and HVAC.

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