How to Choose A Tank Blanketing Valve
WHAT TO CONSIDER WHEN SELECTING A TANK PADDING REGULATOR
Choosing the Tank Blanketing Valve for Your System
It is extremely important to choose the tank blanketing system suitable to handle the required inlet pressure, flow, and set-point for your specific application. Maintaining the vapor pressure in the tank is key to process safety and product quality. The vapor space in process tanks can be affected in a variety of ways: When pumping media in and out; when process temperature changes, when air and/or moisture enters the tank and vapors escape the tank. Most tanks are not perfectly sealed enclosures and as a result, air and moisture can enter the tank and affect the tank contents. Having the right tank pad/de-pad valve will help keep the tank pressure at desired setpoint during these transitions.
The proper valve may be in the form of a direct-operated regulator or a pilot-operated regulator. You may need a pressure reducing valve/ “padding” regulator, or a back pressure valve/ “de-padding” regulator, or BOTH for your system. Jordan valve is here to help you choose the optimal regulator for your application.
Direct-Operated or Pilot-Operated Tank Blanket Regulator. What is the Difference?
Direct-operated regulators respond directly to variations in the controlled process pressure and adjust to provide the necessary flow and pressure to satisfy the system set-point. Pilot-operated regulators have a secondary pilot regulator and sensing line to improve regulator sensitivity for higher accuracy.
Direct-operated tank blanketing valves are sometimes called self-operated valves and are a good choice for those wanting low initial cost, easy maintenance, and reliable low pressure gas control. Jordan Valve direct-operated tank blanketing valves offer:
- low initial cost and easier installation and maintenance
- faster response for reliable tank pad pressure control
- Smaller sizes can maintain low set-points in some conditions when installed following the steps outlined in the installation manual.
Jordan Valve direct-operated models may have internal or external sensing/registration depending on size:
- Direct-operated blanketing valves in smaller sizes (usually under 1-1/2 inch) have internal registration/sensing.
- Larger direct-operated models (1 ½ to 4 inches) use external sensing, providing greater accuracy as long as the installation procedure is followed. (e.g sensing line is straight and short; full size piping is used; etc.).
Pilot operated tank blanketing valves are a good choice for applications requiring higher flows or higher precision and are worth the higher initial capital outlay. Jordan Valve pilot-operated tank blanketing valves offer:
- greater accuracy than self-operated valves
- extremely fast lock-up, reduced valve droop
- more complex design
- can more accurately control to lower pressure set-points
Jordan Valve pilot-operated tank blanketing models all use internal registration / sensing.
For more information about the difference between direct and pilot operated regulators, visit the Fluid Controls Institute (FCI) education website.
How to use API-2000 to choose the right size?
Choosing a tank blanketing regulator means finding the right size, and API-2000 guides engineers in sizing tank blanketing valves. Process set-point and tank capacity are the two main factors for determining valve size. The tank blanketing set-point is determined by the manufacturer. The capacity requirement is determined by the following factors:
- Inbreathing due to product movement out of the tank (Q-displacement)
- Inbreathing or outbreathing due to contraction or expansion of the vapors due to weather or process temperature changes (Q-thermal)
- Location elevation
- Tank insulation
About Tank Blanketing Valve Installation
Following through with proper blanketing regulator installation is just as important as selecting size in optimizing tank blanketing operation. Following manufacturer’s instructions for installation of the regulator and sensing line, also referred to as the control line or impulse line, is the best way to ensure maximum performance in a blanketing regulator.