Fluid Conservation Systems LMIC Electronic Listening Stick User Manual
- June 13, 2024
- Fluid Conservation Systems
Table of Contents
Fluid Conservation Systems LMIC Electronic Listening Stick
Lmic
The Lmic (pronounced “el mike“) is an easy-to-use, low cost, electronic
listening stick and ground micro- phone combined. It is ideal for general leak
sound- ing operations and can be fitted with either a tripod foot (for use as
a ground microphone) or probe rods (for sounding at fittings or in soft
ground).
The control unit is hand-held with a “trigger” opera-
tion and a volume/sensitivity rotary control. An LED indicates operation and
battery status. It can be used to confirm the position of underground leaks
audibly from ground level; sound pipe fittings; penetrate soft ground to
listen for leaks or carry out traditional acoustic surveys.
The Lmic equipment
The Lmic equipment is shown above (note the battery charger and manual are not shown).
Equipment list
- Lmic hand held control unit
- Microphone unit with cable Tripod unit
- 2 probe rods
- AC adapter
- Headphones
- Carry bag
- Instruction manual
Lmic Controls
Top view of the Lmic showing the rotary control for volume and sensitivity.
Bottom view of the Lmic showing the trigger switch and the electrical
connections for the headphones/battery charger and microphone. 
Using the Lmic
The Lmic is simple to operate. Select either the probe rods or the tripod unit
and screw into the microphone unit. (Use the tripod foot on hard ground and
use the probe rods on soft ground or when accessing water pipe fittings).
Connect the headphones to the rear connector and connect the microphone cable
to the forward connector. Put on the headphones and press the trigger button
underneath the hand-held unit to listen for leaks. The volume/sensitivity can
be adjusted using the rotary control.
LED indication
The green LED shows when the unit is operating and the red LED indicates low
battery power.
Care of the Lmic
The Lmic is rugged and showerproof (to IP65) but contains electronic circuitry
and should be handled with care. It should be kept clean and dry and where
necessary cleaned with a damp cloth; abrasive materials must not be used.
Battery Warning
The Lmic contains lithium ion batteries which must not be used under any
circumstances on any other equip- ment if removed. Only batteries supplied by
Palmer Environmental must be used as replacements. Do not short circuit or
misuse these batteries as this may result in explosion or fire.
Battery replacement
Although these batteries are rechargeable they may eventually need to be
replaced. To do this undo the two screws underneath the hand-held unit and
separate the two halves of the Lmic unit. Gently pull out the battery holder
and replace the batteries. When refitting the batteries and battery holder
make sure no wires become trapped.
Charging the Lmic batteries
Connect the charger lead to the rear connector of the Lmic and connect the
charger power lead to the 240V AC supply. The Lmic can then be charged
overnight. An optional accessory is the car cigarette lighter adapter that can
also be used to charge the batteries.
The Lmic connected to the universal 110-240V AC charger
Lmic Operator Guidance
Background It is necessary to practice the technique in order to disinformation to effective acoustic leak detection tinguish between different sounds, recognising background or interfering noises.
All acoustic leak detection methods are based on the nated. It is also essential that other (non-leakage) premise that normal water passage through pipelines noise sources such as consumer draw-off or partially takes place noiselessly. When the water passage is closed valves are eliminated by logical site inspection disturbed a noise is created. Causes can include par-practices prior to any excavation taking place.
Hand probe
Initial pipe blockages, sudden changes in pipe diameter, abrupt changes in pipe direction, pumps or meters in-Hand probe stalled in the pipeline, consumer usage or pipeline damage. Pipeline damage can include holes, cracks or For normal soft ground surfaces the single pointed exsplits, complete pipeline rupture, leaking joints or leak-tension rod should be connected – do not overtightening valves. the screw thread. For direct contact with underground fittings via access covers it may be necessary to use Careful application of leak detection techniques will the second extension rod – remove the single rod and enable the operator to eliminate detected noises gen-connect the extension rod – replacing the pointed roderated by poor pipeline design or consumer usage and again. If the rods have been overtightened, spanner\ to identify leakage due to pipe system damage. slots allow easy removal.
The strength and clarity of noise generated by leaks Surveying will be affected by the water pressure, the size and shape of the orifice allowing leakage, the type of The leak location can be narrowed down by listening ground material around the pipeline, the type of at accessible contact points such as meters, hydrants, ground cover over the pipe, the diameter, wall thick-valves and stop-taps, which provide points of good ness and material of the pipeline and the quantity of sound pick-up particularly if the pipe is metallic. Use water leaking. the hand-probe/extension rod to listen at these points. A small orifice or hole and high water pressure gener-If there are no accessible contact points or if the pipe ally produce a higher frequency noise. Often the noise is of non-metallic material use the microphone foot for level increases around valves, pipe elbows, T connec-listening, placing the foot over the pipe route in the tions, pipe ends, etc. since the partial obstruction in-area of the suspected leak. Move along the pipe route creases pressure and creates some further distur-listening at each accessible pipe- fitting or at regular bance in the water path. positions on the ground until you have identified the area of maximum noise level.
Leak noise is transmitted along the pipeline both
Leak noise is transmitted along the pipeline both through the water and the pipe wall as well as into the Note: When you are listening on pipe-fittings the locaground around the pipe. The noise travels much better tion of the point of maximum noise will probably not through “hard” materials so that the noise travels indicate the leak position, only the fitting closest to the much further along metallic pipes than asbestos ce-leak. The noise level will also appear stronger where ment pipes which themselves are better than plastic there is less thickness of ground or other material for it pipes. Ground material generally provides a poorer to pass through. The leak noise will follow the path of travel path than the pipeline itself. Soft sandy ground least resistance. provides a worse travel path than well compacted ground with a hard paved surface covering.
Pinpointing the leak position
The leak noise can change in strength and pitch as it Pinpointing the leak position involves a process of travels along the pipe or through the ground. The comparing a number of leak noises. Select the most deeper the pipe is buried and the softer the ground the suitable sensor device; the microphone foot for hard more the noise will be dampened. The harder the pipe ground surfaces or the hand probe for soft ground. material, the higher the frequencies detected will be, and the further from the leak the noise will be detected Press the trigger to operate the Lmic and adjust the and the harder it becomes to accurately pinpoint the headphone volume control to a comfortable listening exact point of maximum. level. Once you have listened to the noise through the headphones, release the trigger to switch off the am- Background noise can interfere with leak detection. plifier and move the microphone foot or hand probe to Traffic and machinery noises can travel for consider-the next test position. able distances through both air and ground material and often occur in the same frequency bands as leak Repeat the sequence to listen to each of the test locanoise.
Sometimes it is necessary to use leak detec-tions moving along the pipe route in the directiontion techniques at night when interfering noises are where signal strength is increasing. If the leak noise less. level falls you have passed the leak and should go back and reduce the distance that you move between It is very important to adopt a methodical approach measurements. The loudest leak noise will then indiwhen using any instrument for acoustic leak detection. cate the location of the leak bearing in mind the ground conditions already mentioned.
Technical specification
- Lmic hand held unit/sensor housing
- Piezoelectric high sensitivity sensor mounted in PC-ABS (polycarbonate) housing Single headphone/charger input socket with automatic sensing of device connected.
Connectors
Amphenol military specification connectors for microphone and
headphone/charger connections
Charging
- Universal 110-240V AC charger with 12V DC output
- Car cigarette lighter adapter with 12V DC output (optional accessory)
- 4-pin Amphenol connectors to control unit
Charge time: Overnight charge.
Microphone housing
- High sensitivity piezo-electric sensor mounted in rubber housing with integral strain relief
- Low noise 0.75m cable (detachable) 4-pin Amphenol connection to control unit
Weight: 400g Foot attachment
- Cast metal tripod for ground contact
- Hand probe attachment 2 stainless steel extension rods (each 400mm long)
Weight: 150g
Headphones
Lightweight high quality headphones
Impedance: 16 Ohms 4-pin Amphenol connector to control unit
LE D
- Green = normal operation
- Red = low battery power
Optional accessories
- High specification aviation quality headphones
- Car cigarette lighter adapter with 12V DC output
- Acoustically shielded ground microphone foot, for use in all weather conditions
CONTACT
Fluid Conservation Systems, Inc 1960 Old Gatesburg Rd
Suite 150 State College, PA 16803 Phone
800-531-5465
www.fluidconservation.com
Note: Fluid Conservation Systems, Inc reserves the right to change products, services and/or specifications without additional notice to the consumer.