The DLF Switches are mounted on line with pipes to vessels. Connections can be made by sleeves (threaded or socket welding) or by flanges.

In these types the liquid level is checked by a float integral with a swinging rod placed within the cylindric body. When level rises higher than the preset point, the float makes the output device trip (trip on rise); when level comes down again and exceeds the preset point, the float makes the output device come back to the initial position (reset on fall); between the set and reset points there is always a small gap, named differential, of 30 ±10mm. The inverse function is available too : Trip on fall and Reset on rise. The output can be electric or pneumatic, is snap action and is placed in the housing.

 

The Switches meet the PED and the ATEX standards.
 

APPLICATIONS. Thanks to this way of operating, these Switches can be used in vessels containing industrial liquids with specific gravity from 500kg/m³ up and high pressures, all conditions usual in thermoelectric central stations, nuclear, chemical, petrochemical plants.
 

Body.

Materials : Carb.steel ASTM A106B, stainless AISI 304, AISI 316

Size : Øouter 4” (114,3mm), in thickness as per ASME standards.

Rating : ANSI 150÷600 psi.

For further safety and production simplicity, float, rod and other inner parts are all made in AISI 316 stainless steel.
 

Connection to vessel.

• Sleeves, threaded or socket welding.

• Flanges as per ANSI 150÷600psi.

• Flange as per UNI/DIN standards.

Materials : Carb. steel ASTM A106B, stainless AISI 304 or 316.
 

Housing.

Aluminium casting, electric or pneumatic version :

• With 1 or 2 micros SPDT with simultaneous action;

size : Ø155×200mm, flame-proof EEx dc IIC T6;

1 hole for electric connection : ¾” NPT-F (or ½” NPT-F);

• 1 pneumatic valve On-Off-Vent; Ø125×180mm, water-proof;

3 holes for air connection ¼” NPT-F : inlet, outlet and vent.
 

Differential. 30 ±10mm in the standard case.
 

Outer finish. Switches in carbon steel have the standard painting so realized : first coat in epoxy resin, and outer coat in green polyurethane resin; suitable for corrosive marine environments and tropical climates. Switches in stainless steel are polished and left bare.