Dampers in Oklahoma

Many applications will not require all the following information, but we think that it is a good practice to collect all the data you can before making a choice. ASCO, the solenoid valve people, have developed a simple acronym to help collect the information, TOMSPAVE. Here’s how it breaks down:

• Type – 2-way, 3-way, 4-way, on-off, modulating
• Operation – Normally open, normally closed, universal
• Media – Air, water, steam, oil, etc (remember temp!)
• Size – Pipe size, required GPM, SCFH, PPH, Cv
• Pressure – Inlet pressure minimum and maximum, psi drop
• Atmosphere – Ambient temp, explosion-proof, watertight
• Voltage – Also specify AC or DC
• Extras – Special construction, manual operators, etc

Most HVAC valves will have a brass tag on the neck of the valve. Sometimes it is under valve insulation. Remember to get the information off the actuator as well. Many of us have experience in “backtracking” into the control valve, but all the information you can collect will help us figure out what that tagless valve is.

ASME Codes

Section 1 – Power Boilers & Section 8 – Pressure Vessels

Opening Pressure Tolerances (based on PSI), Blowdown (closing pressure), Seat Tightness, Recommended Operating Gap, Importance of Markings (V, UV…)

Absolutely! Regular blow down will ensure your boiler operates in peak performance for as long as possible. When performing blowdown, please consider the following steps:

1. Before cutting boiler into line, blowdown to reduce the alkalinity. This prevents carryover. Test the water and give blowdowns until the water is just right. Consult with your water treatment specialist to determine frequency and duration of blowdowns.
2. Blow out sediment, mud or scale while boiler is steaming.Important: make certain blowdown valves are closed on idle boilers or scalding water will blow into them.
3. Blow down when boiler has a low load. Sediment settles more under these conditions. Watch gauge glass; don’t leave an open valve.
4. Be careful when blowing down boilers. First, open quick-opening valve slowly; then open slow-opening valve slow enough to prevent shock, but fast enough so valve seat won’t wire draw. To stop blowing down, close slow-opening valve quickly; then close fast-opening valve.
5. Never jam a blowdown valve if it won’t close. Open a few turns fast to clear, then close again slowly. Try this several times to dislodge any scale or sediment. Jamming on scale will wire-draw or score the seats and disc of valve.
6. For cleaning, inspection or repairs, empty cold boiler through blowdown line. Never empty until the boiler is quite cool, or boiler seams and joints may warp and cause leakage.

Essentially valves have these primary functions:

1. Starting and stopping flow.
2. Regulating flow or throttling by change of direction or restriction
3. Preventing Backflow
4. Relieving and regulating pressure.

The secret to good valve performance is selecting the right valve for the service required.

Consider Service Conditions
In selecting the valve which will give the best service and, in turn, keep plant maintenance and operating cost at a minimum, the following things should be considered.
A. Type Medium to be Handled
1. What liquid or gas will the valve handle?
2. Is it a true fluid or does it contain solids?
3. Does it remain a liquid throughout its flow or does it vaporize and become a gas along the way? Does it crystallize?
4. Is it corrosive or erosive?
B. Pressure and Temperature
These may vary throughout the handling system and should be considered in selecting the right valve materials.
C. Flow Considerations
1. Is pressure drop critical?
2. Is valve to be for simple shutoff or for throttling?
3. Is valve needed for prevention of backflow?
D. Frequency of Operation
1. Will valve be normally open with infrequent operation?
2. If operated frequently, will valve design chosen provide maximum wear?

Basic types of valves we carry include:

1. Gate
2. Globe and Angle
3. Check
4. Plug
5. Butterfly
6. Ball
7. Slurry

Special attention must be given to selecting proper valve materials. It is often advisable to choose the valve body bonnet material first and then the trim. Aside from the primary function of the valve (shutoff, throttling, etc.), other factors govern the basic material selection.

1. Pressure-temperature ratings.
2. Corrosion resistance requirements.
3. Thermal shock.
4. Physical shock.
5. Line stresses.
6. Fire hazards.

Trims are generally selected to meet corrosive conditions. In other cases, trims may be selected to solve problems from erosion or other conditions.