Preferred Utilities
Preferred Utilities

Back Pressure Regulating Valves, Model BQ

The Model BQ Back Pressure Regulating Valve is a self-operated spring-loaded back pressure regulating valve.

Application

Back pressure regulating valves are designed to maintain constant supply pressure for generators, boilers, booster pumps, or any other application that requires constant oil pressure.

The valves have three ports--a supply, a discharge, and a return. Oil flow through the return is modulated to maintain constant discharge pressure despite changes in discharge flow. In fact, back pressure regulating valves are commonly installed upstream of shutoff valves. When the downstream valves are shut, the back pressure regulating valve recirculates all of the oil back to the return. This oil circulation loop is often necessary to keep the oil strained, filtered, and warm for use.

Back pressure regulating valves are not to be confused with relief valves. Relief valves are often on/off (not modulating) and can cause pulsation in the discharge line.

Features

Overview

The Model BQ Back Pressure Regulating Valve is a self-operated spring-loaded back pressure regulating valve.  Typically the Model BQ is installed at the far end of the oil supply line, down stream of the boiler fuel metering valves and passes unburned oil to the return line.  Alternately, the Model BQ may be installed upstream of the boiler fuel metering valves.  In both cases, the valve passes oil to the return line in order to maintain a constant supply pressure to the fuel metering valves.

The Model BQ is a ½" NPT valve with cast iron body, bronze trim, composition disc and neoprene diaphragm.  The diaphragm is suitable for use with fluid temperature up to 200° F.  The valve has capacities of 390 GPH for No. 2 or No. 4 oil and 275 GPH for No. 6 oil at a viscosity of 3500 SSU.  The Model V Back Pressure Regulating Valve is recommended for higher flow rates.

Specification

Provide and install a Back Pressure Regulating Valve as shown on the contract drawings.  The valve shall be a ½" NPT Preferred Utilities Manufacturing Corporation, Danbury, CT, Model BQ, with adjustable range from _____ to _____ psig, cast iron body, bronze trim and neoprene diaphragm.

DOCUMENTS & DOWNLOADS

Back Pressure Regulating Valve, Model BQ - Catalog Cutsheet
Back Pressure Regulating Valve, Model BQ - Catalog Cutsheet
Back Pressure Regulating Valve, Model BQ - Datasheet.pdf

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