Types 14480 & 14490
Thermal relief valve


Designed to provide pressure control in systems subject to thermal expansion, the Type 14480/90 relief valve provides accurate repeatable performance with reseating within 10% of cracking pressure or better.

The use of hardened elements operating in a linear bearing cage ensures long life and consistent performance.

A unique feature of this valve is the lock down facility which eliminates the need to remove or disconnect the valve during proof testing of the system.

Lock down facility

Provision is made in the cap for a special lock down screw to be inserted to disable the valve and hold it closed against the increasing pressures applied during testing of the system pipework and components.

This eliminated the need to remove or disconnect the valve during test procedures. When the lock down screw is removed, the valve reverts to its as set condition without further adjustment or re-calibration.

The thread in the cap is a non-preferred size, thereby preventing unauthorised insertion of other types of screw. Lock down screws are not provided with each valve to prevent unauthorised use; they are available on request.

Principal features

Compact design derived from the use of high
performance disc springs

Hardened steel elements operating in a linear
bearing cage provide smooth repeatable
performance

Soft seats are fitted to give a low differential
between cracking and reseating pressures
typically within 10%

Set point is not affected by changes in exhaust
pressure which should not exceed 100 bar

This relief valve conforms to Directive 94/9/EC relating to equipment intended for use in potentially explosive atmospheres and is ATEX (ATmosphere EXplosible) certified.

These valves also conform to the Pressure Equipment Directive 97/23/EC. All valves are CE marked and supplied with a test certificate plus a declaration of conformity.
Marshalsea Hydraulics has been assessed by SGS Société Générale de Surveillance SA and certified as meeting the requirements of ISO 9001:2000 for the design, development, manufacture and servicing of hydraulic pumps, relief valves and intensifiers.

Part no. Pressure range (bar) Connections
inletexhaust
14480 – 03 35 – 345 1/4" NPT male 1/4" NPT female
14480 – 04 345 – 800 1/4" NPT male 1/4" NPT female
14490 – 03 35 – 345 1/4" NPT female 1/4" NPT female
14490 – 04 345 – 800 1/4" NPT female 1/4" NPT female
14491 – 01 35 – 345 3/8" MP Butech 1/4" NPT female
14491 – 02 345 – 800 3/8" MP Butech 1/4" NPT female
14491 – 03 500 – 1,380 3/8" MP Butech 1/4" NPT female
14491 – 04 500 – 1,380 3/8" MP Butech 1/4" BSP female
14494 – 03 35 – 345 1/4" BSP female 1/4" BSP female
14494 – 04 345 – 800 1/4" BSP female 1/4" BSP female
Proof test pressure: 1,000 bar
Materials
External/wetted parts 316 stainless steel
Hardened parts 431 stainless steel
Other parts stainless steel