The DL Swithes are mounted on a side of vessel by means of a flange. In these switches the level is checked by a float integral with a swinging rod : 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 gap, named differential; it is 50 ±10mm in the standard case, but can be also much higher in the case of special versions. 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 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.

 

Body.

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

Size : Øouter 3” (89mm), in various thickness as per ASME standards.

Rating : ANSI 150÷1500 psi.

For further safety and production simplicity, float rod and other inner

parts are all made in AISI 316 stainless steel.
 

Connection to vessel .

• Flanges as per ANSI standards : 150÷1500 psi.

• Flanges as per UNI/DIN standards.

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

Housing .

Aluminium casting, electric or pneumatic version :

• 1 or 2 microswitches 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. 50 ±10mm in the standard case, but can be much higher in the case of special versions prepared upon request.
 

Rod. The rod jutting out into vessel is normally supplied with total length (Rod+Float) of 350mm from the flange, as per the side sketch.

Other lengths can be produced upon request.
 

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