Parker-Meggitt F354 / F355 / F387 / F390 By-Pass Regulators

Fitted in the pump bypass return line, the Parker-Meggitt by-pass regulators keep a constant pressure at a downstream sensing point, such as a venturi, based on the reference pressure supplied to them. They are typically used as secondary pressure controls. Where the best possible low-flow stability is needed, they can also act as the primary pressure control alongside an inline air set demand regulator such as the 4″ F370. In that arrangement, the demand regulator supplies the deadman closure and surge control that a by-pass regulator doesn’t provide.

The range comes in two control styles. The F390 (3″) and F387 (4″) are air set regulators: the reference pressure, either air or fuel, is set 20–30 psi above the regulation pressure you want. The F354 (3″) and F355 (4″) are spring set regulators that work the same way but can be operated by AC or DC solenoids. They can also run on air without needing a set regulated air pressure. Spring set versions can stand alone without deadman control, and when paired with an air deadman they remove the air-to-fuel interface completely.

An optional pump relief feature (suffix E) lets the valve also limit maximum inlet pressure, giving pump outlet protection across a 10–125 psi (0.7–8.6 bar) range. Working pressure is 200 psi (13.8 bar), with peak surge pressure of 275 psi (19 bar).

The range is designed to keep spares and upgrades simple. Every 3″ valve shares the same body and piston design, as does every 4″ valve. That means an F390 or F387 can be converted in the field to an F354 or F355 without removing the main body from the line. Bodies are aluminium as standard, with ductile iron available as a special order.

For correct operation, the sense line should have an internal diameter of at least 0.375″ (9.5 mm). The inlet piping should run straight for 15″ (381 mm) at the same internal diameter as the valve. Contact BMS to discuss the right regulator and control arrangement for your fuel system.

Our certified engineers provide nationwide installation, calibration and ongoing maintenance for selected products in our range.
Book installation with your order and receive 50% off your first post-installation service visit. Speak to an engineer for details. Call 0345 230 7887 or email sales@bms-ltd.com.