LT7 Compact Single Channel Leak Detector

LT7 Compact Single Channel Leak Detector Overview



The LT7 is a compact single-channel only leak detector. It is designed for cost-sensitive applications where the flexibility and expandability of our other models is not required. It is available in two major configurations, to suit both conveyor fed and static test fixture applications.


LT7 Leak Detector


1. Leak Tester Features

The LT7 series of leak testers have many advanced features:

1.1. High accuracy leakage measurement

The system uses a piezoresistive semiconductor strain gauge pressure transducer with a low noise amplifier and high speed analog to digital converter. This minimises measurement errors.

1.2. Flexible bottle transport system

Timings can be easily adjusted to optimise bottle transport, where required, without sacrificing test time.

1.3. Microprocessor control system

Allows quick customization for special needs.

Allows easy expansion of system to include extra facilities even after installation.

1.5. Cost Effective

The leak tester electronics has been integrated onto a single PCB. The circuit card has been designed and programmed specifically for this application. Great care has been taken to ensure that the system is easily re-programmable, and reliable. This means that the performance and cost limitations of using a bought-in Programmable Logic Controller are avoided.

2. Options

The leak tester design is highly flexible with respect to software, electronics, pneumatics and mechanics. This allows a wide range of options to be added at any time, even after installation.

2.1. Choked Bore / Ovality Test

A probe fitted to the test head checks whether the neck is occluded or deformed.

2.2. Height Check

A fibre-optic sensor checks that the bottle is not too tall. This can detect folded over base flash on some bottles, as well as neck flash.

2.3. Automatic self test

This can be used to periodically check the operation of the leak tester. Every 100 cycles (or any other number), a valve is turned on which introduces a known leakage into the system. A leak test is then performed. If the known leak is not detected, then the system will halt with an alarm.

This technique can reduce the use of "test bottles" to a minimum.

2.4. Conveyor halt during test

The conveyor motor can be driven directly from the PCB, stopping during the leak test. This is recommended since it improves leak tester accuracy and bottle stability. However, this is not always practical when the leak tester is attached to an existing conveyor system.

2.5. Auxiliary Sensors

Spare inputs are available which can be used to connect other sensors which examine the bottle during the leak test. Examples might be label sensors, flash detection sensors or vision systems. The leak tester would fail the bottle if any of these inputs are triggered.

2.6. Bottle transport options

A variety of bottle transport options can be fitted to replace the standard method. It is recognised that the standard method may not always be suitable, although we have found that is the most flexible as well as the most cost effective. Other methods include side clamps and holding moulds.

2.7. Stabilisation Plate

A pneumatically operated mechanism can be fitted to the infeed of the leak tester. This is only required when the conveyor is to be fed directly from the output of a blow moulding machine with violent take-out movements. The queue of bottles is supported by the plate when push-out occurs. The plate then opens, allowing the bottles to travel down the conveyor.

2.8. Vacuum Operation

The system usually pressurises the bottles during the leak test. However, it is possible to supply the system for vacuum operation where required.

2.9. Special test pressure

The system test pressure is adjustable over a limited range (see specification). If this range is not sufficient, a different transducer can be fitted to allow any test pressure desired.


3. Specification

Electrical Power Supply 115 or 230 VAC single phase
Electrical Power consumption 30 VA (Leak tester) 300 VA (Conveyor) maximum
Air Supply 4-10 bar
Air Consumption 0.1-1 litre / minute typical
Minimum bottle volume No lower limit
Maximum bottle volume 20 litres (unit will still work with any volume, but cycle time would be improved using another model).
Test Pressure Adjustable, 5 - 70 mB. This range can be changed on request.
Cycle Time 1.0 - 20.0 seconds, adjustable.
Hole Size Detected Dependent on cycle time and container size. (See graph below). For a 500ml bottle and at 20 bottles per minute, the hole detected would be 0.15mm.
Leak Test Method Pressure Decay, Auto-zero, Auto-Scale.
Transducer Piezoresistive semiconductor strain gauge, 0.00 - 80.00 mB, 0.1% resolution, 20 x Overpressure Protection.