LDU22 - Overpressure Monitoring of DW Steel Tanks and Fill/Suction Lines

SGB LDU22 Leak Detection Unit

The LDU22 is a leak detection unit for double-walled tanks and pipework at petrol filling stations, operating on the principle of air overpressure in the interstitial space.

A key advantage of the LDU22 is that it is designed for outdoor mounting on petrol filling stations. When installed close to the tank farm, it can significantly reduce the amount of ducting and air-tubing required, and removes the need to route air lines back to the shop/kiosk — helping to improve site safety and simplify installation.

Standard Features

• Green status/operation light
• Red alarm light
• Flashing beacon on top of the housing
• Audible alarm sounder
• Acknowledge (alarm reset) button

Combined LDU22 versions can display tank alarms and pipe alarms separately.

Available Types

• LDU22 T280 – for tanks with diameter ≤ 2.5 m and minimum interstitial test pressure of 400 mbar
• LDU22 T330 – for tanks with diameter ≤ 3.0 m and minimum interstitial test pressure of 500 mbar
• LDU22 P1.1 – for pressureless pipework (e.g. fill and suction lines)
• LDU22 P2.0 – for pressureless pipework (e.g. fill and suction lines)
• LDU22 P3.5 – for pressurised pipework with max delivery pressure of 2.5 bar

Common Combined Configurations

• LDU22 T280 / P1.1
• LDU22 T280 / P2.0
• LDU22 T280 / P3.5
• LDU22 T330 / P1.1
• LDU22 T330 / P3.5

System Capacity (Outputs)

• Up to 18 underground tanks
• Up to 32 pipes
• Combined: up to 28 tanks/pipes
• Expansion is only possible in steps of two.

Applicable Tanks and Pipes

• Tanks: maximum internal overpressure of 500 mbar, with interstitial space pressure resistance of 400 mbar or 500 mbar
• Pipes: interstitial space pressure resistance of at least 5 bar
• Note: interstitial spaces must not be classified as Zone 0

Stored / Conveyed Products

Suitable for water-polluting liquids. Any potentially explosive vapour-air mixtures that may occur (including mixtures created by contact with air, humidity, condensation, or the materials used) must fall within:

• Explosion group: II A to II B
• Temperature class: T1 to T3
• Examples: gasoline (petrol), diesel, AdBlue

Installation

• Install outside the hazardous (Ex) area, or in areas where Zone 1 does not exceed a height of 1 metre

Housing / Protection Class

• st-box: painted sheet steel housing / IP43
• ss-box: stainless steel housing / IP43

Options

• FC dry filter monitoring: visual and audible alarm when the dry beads are depleted
• M: digital pressure display (inside the upper housing) for easier maintenance
• H: heater (extends operating range to –40 °C to +60 °C)
• MH and FCMH variants available

Temperature Range

• Unheated: –10 °C to +60 °C
• Heated: –40 °C to +60 °C

Pneumatic Connection

• QU8/6: quick union for polyamide (PA) hose 8/6 × 1 mm

The requirements in the official documentation must be complied with.