Mark 33 Series Electric Motor Control Valve

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Boiler feedwater valve with an industrial grade motor in a die-cast magnesium housing.
Accurate and low turbulence operation given by the sliding gate seat.
Motor and gear train are immersed in oil for increased durability.

The Mark 33 series is a boiler feedwater control valve that uses a sliding gate seat which helps to minimise turbulence and gives a shorter stroke for a more accurate operation. Overlapping gate seats give a tight shutoff that is ANSI Class IV rated.

The valve motor is encased in die-cast magnesium and has been given a NEMA3 protection rating. An oil-immersed motor and gear train ensures a durable operating system.

A jorcote seat comes as standard or a chrome planted seat can be chosen as an option. The body is constructed with ductile iron, bronze, carbon steel and stainless steel. Both threaded and flanged end connections are available.

Motors have an ambient temperature range of between 4°C and 66°C and sizes are from ¼" up to 2”. A 24 VAC is required to power the valve with an optional transformer being available for 120VAC.

Key specifications

Sizes	MK33: 1/4" through 2" (DN8 through DN50) MK331/332: 1-1/2" & 2" (DN40 & DN50)
End connections	Threaded Flanged
Body materials	Ductile Iron Bronze Carbon Steel Stainless Steel
Trim materials	303SS for DI, BZ or CS body valves 316SS for SS body valves
Seat materials	Jorcote on SST - Standard Chrome plated SST - Optional
Packing	Spring loaded Teflon (to 500°F/260°C); braided (above 500°F/260°C)
Service	steam, water, air, oil, gas and chemicals
Shutoff	ANSI Class IV
Seat Interchangeability MK331/332	1-1/2" with 2" (DN40 with DN50)
Power Requirements	24 VAC, 50/60 Hz (optional transformer required for 120 VAC)
Command signals	Proportional control (0-135ohms); on-off control; current command (4-12, 4-20, 12-20mA DC standard); voltage command 2-10 VDC
Operating time (approx)	30 seconds
Ambient temperature limit for motors	-40°F to 150°F