The regulator connected to the source container is called the first-stage regulator and has a key safety function that reduces the gas pressure of the container to a lower operating pressure. The regulator is usually connected to the service valve on the container through a connector called a "pigtail" or "pigtail", both of which are flexible metal connectors.
The pigtail is usually 0.25 inches. The copper tube between the brass fittings makes it very flexible. Pigtails usually consist of 0.375 inches. Tube, which makes it less flexible. The larger pipe diameter in the pigtail allows a greater steam flow than the pigtail.
Both types of connectors have various sizes and styles. The connection to the service valve should always be POL, but the connection to the regulator inlet may vary depending on the regulator selected. These flexible metal connectors play a very important safety role during the start-up phase of the propane vapor distribution system. The Propane Education and Research Council has educational materials for designing and installing steam distribution systems-available at propane.com and learning centers.
The National Fire Protection Association stipulates that the connection between the storage tank and the regulator must be connected directly or through a flexible connector to the outlet of the shut-off maintenance valve. When used in fixed containers of 2,000 gallons or less, the length of the connector must not exceed 5 feet.
Flexible metal connectors (pigtail or pigtail) provide a critical safety feature because they allow movement in the gas pipeline of the container. This flexibility reduces the pressure on rigid pipes and fittings, absorbs vibrations and reduces the impact on the container piping system.
Flexible metal connectors (pigtails or pigtails) vary in length, and many connectors produced by manufacturers are straight (not curved). Because the connectors are flexible, service technicians can bend or cycle them for any number of applications, ensuring that the regulator is correctly positioned under the container dome. There are also pre-bent connectors for specific applications, such as underground containers where space is tight.
Kink in flexible connectors should always be avoided. This restricts the flow of steam and creates a place for debris to gather. Excessive bending or twisting can put pressure on the pipe, which can cause rupture and cause leakage.
It is important to understand how flexible connectors react with propane vapor. When hydrocarbon (propane) gas flows through, the inner surface of the copper flexible connector becomes brittle. Copper sulfate will form along the copper surface, causing the flakes to loosen and enter the inlet of the regulator. Therefore, you do not want to reuse or relocate the installed flexible connector. Propane professionals must pay attention to how debris affects the safe operation of the propane system.
A flexible connector (pigtail or pigtail) can capture or capture debris from the container. Debris will obviously cause blockages, which will hinder the flow of gas vapor to the regulator. Debris such as corroded (copper sulfate) flakes or excessive thread sealant will get stuck on the seat plate, causing the regulator orifice to not be completely sealed, preventing the regulator from reaching the locked state. Any type of debris that enters the inlet of the regulator will cause the regulator to "squirt", which will cause the outlet pressure to increase, which will cause the internal safety valve to activate.
Although it may be a small item in the entire propane vapor distribution system, remember that if you want to replace the regulator or replace the container, be sure to replace the flexible metal connector (pigtail or pigtail). By selecting and installing these connectors correctly, you can ensure the safety of the operating system, thereby helping to ensure that you provide your customers with clean and efficient propane energy.
Randy Warner is the product safety manager for Cavagna North America. You can contact him at randywarner@us.cavagnagroup.com.
Note: The views and opinions expressed here are solely those of the author and should not be interpreted as those of LP Gas Magazine or any of its staff.
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