Type 1250
Lockout relay valve



The manual lockout relay Type 1250 (normally closed) is a pilot-operated, three port, two position valve with manual-open actuator. It may be side mounted or panel mounted with a maximum panel thickness of 4 mm.
In the 'locked out' position, service line pressure (Port 3) is vented to tank (Port 5) while the supply pressure (Port 4) is blocked. In this position the relay will function if a pressure supply is established at the pilot (Port 1). Thus a closing device must be connected downstream of the relay output with the relay pilot then connected downstream of the closing device, as illustrated in the schematic diagram.
With the remote closing device energised (actvated), the relay can be opened; i.e., supply pressure (Port 4) connected to service (Port 3) with tank (Port 5) blocked by depressing the operating knob – the supply pressure will assist the		 manual operator after approximately three-quarters of its travel to ensure positive operation of the valve changeover. The valve can only be closed by removal of the pilot supply pressure by a separate closing device, e.g., either a solenoid or a three-way manual valve – not by the manual action of pulling out the valve knob.
The valve slide (supplied in a normally closed configuration) has a 'block before bleed' action – for example, the tank port is isolated before the pressure and service ports are interconnected.
Specifically designed for use in wellhead safety shutdown systems, the relay is manufactured from 316 stainless steel and CA104 aluminium-bronze materials which meet the requirements of NACE Standard MR-01-75 (latest revision as applicable).

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

Operating parameters
Working/pilot pressure 250 bar (3,625 psi) max.
69 bar min pilot operating pressure.
Operating media Mineral oils, water, water-glycol mixtures with corrosion inhibitors.
Connections 1/4" NPT tapped all ports.
Flow rate, nominal 27 litres/min (6 imp galls/min).
Working temperature –20°C to + 160°C.
Recommended filtration 3 micron.