FITOK RVSS-FL4-6-C Proportional Relief Valve, 1/4 in. FITOK

RVSS-FL4-6-C is a FITOK RV Series proportional relief valve in 316 stainless steel with 1/4 in. FITOK tube fitting ends and an FKM seal. The catalog gives a set pressure range of 4,500 to 6,000 psig (310 to 414 bar) with the red spring, a 0.14 in. (3.6 mm) orifice and an inlet limit of 6,000 psig.

Proportional relief for protecting instruments and small circuits

A proportional relief valve opens gradually as pressure rises above the set point, instead of popping fully open at once. That gradual action suits protection of pumps, hydraulic circuits, instruments and test lines where the flow to be vented is small. The set pressure is changed with an adjusting screw, and the red spring defines the 4,500 to 6,000 psig range of this code.

In the code, RV is the proportional relief series, SS is 316 stainless steel, FL4 is a 1/4 in. FITOK tube end, and the final 6 and C elements follow the catalog ordering table for spring range and seal. The catalog lists the spring kit for this range as 7PRV-SP6-C-B (red) and the FKM seal kit as VI-RV-6.

Catalog data

• Set pressure tolerance of plus or minus 3 psig or 5 percent at 60 F to 80 F.
• Maximum outlet pressure of 1,500 psig.
• Replaceable spring kit and seal kit for field adjustment of range.
• Orifice 0.14 in. (3.6 mm) with 1/4 in. FITOK tube ends.

Technical specification

Specification of RVSS-FL4-6-C

Important limits stated in the catalog

The catalog warns that proportional relief valves are not certified to ASME or any other code, and that they are not a safety accessory in the sense of the Pressure Equipment Directive. They are for system protection where a code-stamped safety valve is not required. Where a regulatory relief device is needed for a pressure vessel, a certified safety valve must be used instead.

Spring range is the main choice. The set pressure should lie inside the spring range with some margin from its extremes so that adjustment stays stable. Ask for the spring kit with the correct color code if the system pressure changes later.

Remember the outlet limit of 1,500 psig: if the vent line can see back pressure, size and route it accordingly.

Setting and maintenance

Set the valve on a test bench or in a controlled pressure test before putting it in service. Turn the adjusting screw slowly, watch the pressure at which flow begins and lock the setting once confirmed.

Inspect the FKM seal when the system is serviced. If it swells or hardens, replace it with the seal kit listed in the catalog.

Use in the region

General engineering note: small proportional relief valves are used on hydraulic power units, chemical injection pumps, calibration benches and gas sampling skids in oil, gas and industrial plants. They limit pressure spikes that could harm gauges and transmitters. Confirm the system design basis and regulatory requirements with your engineer.

Related FITOK items

Needle valves, check valves, ball valves and tube fittings in the same size can be quoted for the relief circuit. Spare spring and seal kits named in the catalog can be requested together with the valve.

Frequently asked questions

Is this relief valve ASME certified?

No. The catalog states that proportional relief valves are not ASME or code certified.

What set pressure range does the red spring cover?

4,500 to 6,000 psig (310 to 414 bar).

What is the maximum outlet pressure?

The catalog gives 1,500 psig as the maximum outlet pressure.

Which spare kits are listed?

Spring kit 7PRV-SP6-C-B (red) and FKM seal kit VI-RV-6.

Does Seven Star LLC act as a FITOK distributor?

No, we are an independent supplier in Muscat and supply FITOK items on request rather than acting as a FITOK channel partner.

Documents and quotation

Need RVSS-FL4-6-C? The FITOK datasheet and user manual are attached to this listing. Seven Star LLC (independent supplier, Muscat) can quote the item and arrange supply on request; list quantity and site location in your enquiry. Verify the order code and electrical options in the documents before ordering. Other products are in the category page.