AEROTECNICA COLTRI MCH 14 TECH NITROX SERIES User manual

Low and High pressure
Compressors
MCH 14 TECH NITROX
Low and High pressure
Compressors
MCH 14 TECH NITROX
Revision: DOCMCH14TECH-NITROX-09-01
INSTRUCTION
MANUAL
VERSION: English
Special equipment and compressors for underwater activities

2
GUARANTEE AND ASSISTANCE
1.1 Guarantee ............................................................................................................................ 8
1.2 Assistance........................................................................................................................... 8
1
2
USE IN BRIEF
TECHNICAL DESCRIPTION
2.1 Operatingprinciple ............................................................................................................... 10
2.2 Description of the pumpunit highpressure compressor ....................................................... 12
2.2.1Crankcase -High pressurecompressor...................................................................... 13
2.2.2 Valve headunit - Highpressure compressor ................................................................ 14
2.2.3Safety valves-High pressurecompressor ................................................................... 14
2.2.4Lubricating unit............................................................................................................ 14
2.2.5Pressure maintenancevalve- Highpressurecompressor ............................................ 15
2.2.6 Coolingpipes - Highpressure compressor .................................................................. 15
2.2.7 Filters -High pressure compressor.............................................................................. 15
2.2.8Pilot valves .................................................................................................................. 16
2.2.9Frame andsound-proofedcasing -Highpressure compressor..................................... 17
2.3 Machine control -High pressure compressor ....................................................................... 17
3TECHNICAL CHARACTERISTIC
3.1 Technical characteristics of the pump unit............................................................................ 18
3.1.1 Sizes and weights....................................................................................................... 18
3.1.2Machine seriesMCH14 TECHNITROX....................................................................... 19
3.2 Noise level ........................................................................................................................... 20
4PRECAUTIONS FOR USE AND MAINTENANCE
4.1 Machine areadiagrams ........................................................................................................ 22
4.1.1Safety devices............................................................................................................. 23
4.1.2 Residual risk areas ..................................................................................................... 25
Usein brief..................................................................................................................................... 7
Index

3
5
UNPACKING AND HANDLING THE MACHINE
5.1 Unpackingthe machine........................................................................................................26
5.2 Pack contents...................................................................................................................... 27
5.3 Handlingthe machine........................................................................................................... 27
6
INSTALLATION
6.1 Positioning........................................................................................................................... 28
6.2 Connections......................................................................................................................... 29
6.2.1 Connecting the extension for the air intake .................................................................. 29
6.2.2 Connecting thefilling hoses......................................................................................... 33
6.2.3 Electrical connections................................................................................................. 34
CONTROL PANEL
7.1 Controlpanel........................................................................................................................ 35
7.2 Indication andcontroldevices .............................................................................................. 36
7
START-UP
8.1 Filling themachine............................................................................................................... 38
8.2 Checks ................................................................................................................................ 39
8.3 Calibrateanalyzers .............................................................................................................. 42
8.4 Low pressure compressorPilot Valve ................................................................................... 43
8.4.1 Pressureadjustment ............................................................................................................ 43
8.4.2 Differentialpressure adjustment ........................................................................................... 43
8
USE
9.1 Preliminaryoperations ......................................................................................................... 43
9.2 Filling the cylinders .............................................................................................................. 46
9
Index

4
10 MESSA FUORI SERVIZIO E
SMANTELLAMENTO MACCHINA
10.1 Instructionsfor extendedstorage ......................................................................................... 58
10.2 Disposalof wasteproducts .................................................................................................. 58
10.3 Dismantlingthe machine...................................................................................................... 59
MAINTENANCE
11.1 Generalnotes ................................................................................................................. 61
11.2 Preventivemaintenance................................................................................................... 61
11.3 Changing thelubricant oil................................................................................................ 62
11.4 Checkingthe drivebelt.................................................................................................... 64
11.5 Suction filtre -low pressure compressor ......................................................................... 64
11.5.1 LP Moisture/Oil Vapor Filters -low pressure compressor ................................................ 65
11.5.2 Suction filtre - high pressurecompressor ........................................................................ 67
11.6 Activated carbonfilter andmolecular sieve- high pressurecompressor........................... 69
11.7 Filling hose- High pressurecompressor ......................................................................... 71
11.8 Inlet anddischarge valves- Highpressure compressor.................................................... 71
11.9 Valves heads -High pressure compressor....................................................................... 72
11.10 Cylinders -Highpressurecompressor............................................................................. 73
11.11 General maintenance instructionsfor thelow pressure compressor ................................ 73
11.11.1 Pressuredischargevalve................................................................................................. 73
11.11.2 Tankdrainagevalve ......................................................................................................... 73
11.11.3 Pressureon/off................................................................................................................ 74
11.11.4 Belts............................................................................................................................... 74
11.11.5 Compressorvalves .......................................................................................................... 74
11.11.6 Centrifugaldischarger anddischargepressure valve ........................................................ 74
11.11.7 Controlvalve.................................................................................................................... 75
11.11.8 Pressure interstagedischargevalves .............................................................................. 75
11.12 Maintenance programme................................................................................................. 76
11
TROUBLESHOOTING
12.1 List of faults ......................................................................................................................... 76
12
Index

5
SPARE PARTS
15.1 Exploded viewof the machineparts .................................................................................. 89
Crankcase ........................................................................................................................ 91
Piston rod unit...................................................................................................................93
Cylinderunit...................................................................................................................... 95
Valveheadunit.................................................................................................................. 97
Coolingpipes .................................................................................................................... 99
Filtering system ................................................................................................................ 101
Condensateseparator ....................................................................................................... 103
Pulley - Crankcaseand Cylinder -Low pressure compressor ............................................ 104
Piston rod unit- Low pressure compressor ....................................................................... 105
Cylinder, valve andfilter unit- Lowpressure compressor ................................................... 106
Description of the pump unit low pressure and pipes........................................................ 107
15
MACHINE DIAGRAMS
14.1 Compressiondiagram .......................................................................................................... 84
14.2 Compressiondiagram -Highpressure compressor .............................................................. 85
14.3 Electricaldiagrams .............................................................................................................. 86
14
Index
16
ENCLOSURE
16.1 Enclosure ......................................................................................................................... 108
REGISTRER
13.1 Register ............................................................................................................................... 83
13

6
To makethe manualeasier toread, thefollowing termshave beenadopted:
DANGER
The term DANGER is used when failure to comply with the regulations or tampering with the
parts could lead to serious injury or even death.
WARNING
The term WARNING is used when failure to comply with the instructions could cause damage to the
machine and other parts associated with the same or to the surrounding area.
LABELAPPLIED TOTHECOMPRESSORS
To protectexposedpersons orobjects, aspecialbooklet entitled“SAFETYREGULATIONS”issupplied
withthe machine andmust beconsidered anintegral partofthe CompressorInstruction Manual.
This manual is the property of AEROTECNICA COLTRI S.r.l. and any copying of the same, even partial, is
prohibited.
Use in brief

7
The following information must be referred to and applied only when this manual and the
“Safety regulations” manual have been read and their contents have been understood and
assimilated.
- Check whether or not the area where the machine is installed has suitable ventilation
(seechapter 6.1).
- Ifthe machineisinstalled inaplacewithoutthe requiredcharacteristicsabove, connecttheairintake
extension(see chapter6.2.1).
- Connect the filling hoses to the machine (see chapter 6.2.2).
- Connect the switchboard to the mains power supply (see chapter 6.2.3).
- Checkthe level ofthe lubricatingoil inthe pumpunit(see chapter8.2). Ifthe levelis too low,turn off
the machine and add or change the oil (see chapter 8.1).
- Turn on the machine using the main switch (see chapter 7.1).
- Checkthe directionof rotationof themotor.Ifthedirectionofrotationdoesnotcoincidewiththeone
shown on the belt guard, turn off the machine and invert the two phases on the main power supply
(seechapter 7.2).
- Checkthe operationof thesafety valve(see chapter9.1).
- Check for wear on the cylinders to be filled (see chapter 9.1).
- Set the pressure switch on the control panel to the refill pressure value given on the cylinder
(seechapter 8.1).
- Fit the hose attachment on the cylinder and check that the taps on the hose are open
(seechapter 9.2).
- Turn on the cylinder tap and start up the compressor (see chapter 9.2).
- When the filling operation has been completed, the compressor is stopped automatically by the
pressure switch, turn off the cylinder and the hose taps.
- Press the pressure bleed button and disconnect the cylinder attachment (see chapter 9.2).
USE IN BRIEF
Use in brief

8
GUARANTEE AND ASSISTANCE
AEROTECNICA COLTRI S.r.l. guarantees itscompressorsagainstanydesign ormanufacturingdefect
or fault and against any fault in the materials for a period of twelve months from the delivery of the
machine. Thecustomer must inform AEROTECNICA COLTRI S.r.l. inwritingof anyfault and/ordefect
that may be found within eight days from its discovery by means of a registered letter with advice of
receiptor telegramme,otherwise theguarantee willbecome nulland void.
The guarantee is only valid against faults or defects that may arise with the compressor used under
properoperating conditionsaccording totheinstructions givenin thismanualandwiththe maintenance
carriedout atthe intervalsas providedfor.
The guarantee expressly excludes any faults arising as a result of improper use of the machine, of
atmospheric agents and of damage due to transport; the guarantee does not cover the expendable
materials and materials required for the periodic maintenance which are at the customer’s entire
expense. The guarantee will, in any case, become automatically null and void if the compressor is
tampered with or if it has been serviced by technicians who are not authorized to do so by
AEROTECNICA COLTRI S.r.l.
Any compressor that is acknowledged to be faulty due to defects in the design, manufacturing or
materials used, will be repaired or replaced free of charge by AEROTECNICA COLTRI S.r.l. at its
factory in San Martino della Battaglia (BRESCIA). The customer will be responsible for the costs of
transportand carriageaswell asfor anyspare partsand expendablematerials.
If it should be necessary for service to be carried out under the guarantee at the customer’s premises,
the latter will be responsible for the travel and transfer costs for the staff sent out by
AEROTECNICACOLTRI S.r.l.
Taking delivery of the machine and/or of any faulty components or the transfers for the inspection of
faultsand/ordefectsasnotifiedby thecustomer,will not,however,denoteanyimplicitacknowledgement
regardingthe effectivenessofthe guarantee.
Repairsand/or replacementsmade by AEROTECNICA COLTRI S.r.l. duringthe guaranteeperiod will
not extend the duration of the same.
Acknowledgment of the guarantee does not itself imply any liability for compensation on the part of
AEROTECNICACOLTRI S.r.l.
AEROTECNICA COLTRI S.r.l. does not assume any responsibility for injury to persons or damage to
propertyor forany otherdirect orindirect damage(lossofproductionor missedprofit, etc.) thatmay be
attributableto faultsor defectsof thecompressor,except forthose casesin whichaserious faultcan be
attributed to the company.
1
1.1 Guarantee
1.2 Assistance
heAEROTECNICACOLTRIS.r.l. techniciansareavailableforanykindofroutineoradditionalmaintenance
work.
The request for technical assistance must be sent to AEROTECNICA COLTRI S.r.l. at the following
address: AEROTECNICACOLTRI S.r.l.
Via Colli Storici, 177
25010San Martinodella Battaglia(BRESCIA)ITALIA
Fax:[phone]
e-mail:[email protected] Guarantee and assistance

9
This chapter provides a technological description of the machine and its main components.
2.1 Operating principle ............................................................................................................ 10
2.2 Description of the pump unit............................................................................................. 12
2.2.1Crankcase .................................................................................................................. 13
2.2.2 Valve head unit ......................................................................................................... 14
2.2.3Safety valves.............................................................................................................. 14
2.2.4 Lubricating unit......................................................................................................... 14
2.2.5Pressure maintenancevalve ..................................................................................... 15
2.2.6 Cooling pipes ............................................................................................................ 15
2.2.7Filters ......................................................................................................................... 15
2.2.8 Pilot valves ................................................................................................................ 16
2.2.9 Frame and sound-proofed casing............................................................................. 17
2.3 Machine control ................................................................................................................. 17
TECHNICAL DESCRIPTION 2
Technical description

10
2.1 Operating principle
1
Thismodel isprovided withtwo compressors,the
firstislowpressure(superior)and thesecondhigh
pressure (inferior); 2 stage of compression with
forced air cooling and 3 stages of compression.
(Fig.2).
The filling stations in the “MCH 14 TECH
NITROX” series are of the semi-soundproofed
type (Fig. 1).
2
This system supplies to output percentages nitrox in oxygen of 22% to 40% for volume.
The alimentacion of the low pressure supplies air tothe membrane and the membrane supplies nitrox
thehigh pressurecompressor.
Technical description
WARNING:
THEFILLING STATION PRODUCESRESPIRABLE AIR/NITROX.

11
This system supplies a breathable gas stream consisting of an elevated oxygen content relative to
normalatmosphericcontent ofapproximately21%O2byvolume. Thistechnique employsgasseparation
technologyutilizingapermeablemembraneto separatecertaingas moleculesfromother gasmolecules
allowinga controlledflow ofoutput gassesof differingoxygen concentrations.
Thissystem producesDNAx Nitroxin oxygenconcentrations of22% to40% atmaximum pressuresof
3200- 3700PSI. A supplygas, inthis case,“Grade-E”air,will berequired. Thissupply gasis fedatlow
pressure(145-185 PSI)to theinput portof themembrane. Thegasstreamis fedthrough athermostat-
controlled heater. As the gas moves through this assembly, its temperature is raised to
35° (110 degrees F). The purpose of this heater is to even out the variations in gas temperature and
produce a more linear performance curve. Once through the heater, the input gas is allowed to pass
through the membrane. As the gas passes through the membrane, the gas volume applies pressure
againstthe insidewallsof thepermeablefibers resultinginthe migrationacrossthe wallofvarying levels
of the different constituents of air. Gas volumes of desired O2concentrations are achieved in this
manner. In this stage the normal oxygen content of the “Grade-E” air second the norms UNI EN 132,
CGA-Eand DIN 3188(20.9%) israised tooutput percentagesupwardsof 23%to 40%.
A needle valve in the outlet stream of the waste gas (nitrogen) controls the relative O2concentrations
whileinput pressureregulationallows controloftheoutputvolume ofthemembrane. This outletvolume
control is required to balance the input requirements of the high-pressure compressor. As the gas
volume of desired oxygen concentration is produced it is contained and directed to the inlet port of the
high-pressurecompressor. Anoverpressure checkvalveisinstalledin theinletfittingof thehigh-pressure
compressor to protect the compressor from over pressurization of the first stage. Negative pressure
protectionisaccomplishedinthesamemannerby installinganunder-pressurecheckvalvein theambient
air intake side of the membrane output fitting.
As the gas volume is subsequently compressed, it is alternately cooled and raised in pressure again
until it reaches its final design output pressure. Final filtration and purification is accomplished at final
compressordischarge.
Product gas “DNAx” nitrox is available at desired oxygen concentrations (up to 40% O2by volume) at
maximum pressures of 3200 - 3700 PSI, for filling Nitrox Storage Bottles or SCUBA cylinders.
Typical Specification for Air :
O2Percentage: ..................................20-22%
CO2:.................................................1000 PPM
CO: ..................................................10 PPM
Hydrocarbons:..................................25 PPM
Water:..............................................67 PPM
DewPoint: .......................................- 50° F
Oil & Particles:................................. 5mg/m3
Odor:................................................Nessuno
Technical description

12
Description of the pump unit -
High pressure compressor
Technical description
2.2
Thepumping unithasthe taskofproducing compressedairat highpressure(200-300bar)and purifying
it by means of the decantation and filtering systems until it reaches a level of purity equal to or higher
thanthe limits setby thestandards DIN3188 -UNIEN 132- CGA/E,or toincrease the pressureof the
gasinhaled (onlyinert -non-explosive gases).
This unit consists of the following components (Fig. 3-4):
3
Table 1
4
N° Description N° Description
1Intake filter 12 2nd stage safety valve
21st stage head 13 Crankcase
32nd stage head 14 Filter-holding bracket
43rd stage head 15 Fan
51st stage cylinder 16 Oil cap
62nd stage cylinder 17 Final condensate separator
73rd stage guiding cylinder 18 Condensate separator between stages
81st-2nd stage cooling pipe 19 Condensate drain connection
92nd-3rd stage cooling pipe 20 Maintenance valve
10 Final cooling pipe 21 Pipe-fastening bracket
11 1st stage safety valve 22 3rd stage or final safety valve

13
Thecylinders aremade ofcastiron (Fig.7), while
the pistons are made of aluminium and have
traditional multiple compression rings. The high
pressure stage piston has an anti-wear coating
andthe relevantcylinderis givenaself-lubricating
treatment.
7
2.2.1
Crankcase - High pressure compressor
5
The crankshaft, the pistons and the cylinders
also form a part of this unit.
The crankcase (Fig. 5) is made of aluminium
alloy, the two flanges with the ball and roller
bearings that support the crankshaft are oil-
tight with the crankcase due to the O-Rings
fitted.
The crankshaft and the connecting rods turn
exclusively on roller or ball bearings(Fig.6).
The three connecting rods are fitted on the
crankshaft with a single crank angle.
6
Technical description

14 Technical description
The head unit includes the discharge and inlet
valves.
The head of the 1st stage is of a lamellar type and
includes both the inlet and the discharge.
Theinlet anddischargevalves arelocateddirectly
in threaded seats on the 2nd and 3rd stage heads.
Theinlet valvescan beremovedusingthespecial
pinwrench(cod.SC000480),havingfirst removed
theheads.
The discharge valves can be removed from the
outside.
SeeChapter 11,“Maintenance”.
The purpose of the safety valves (see figure 5) is to protect the machine (and the cylinders) from
overpressure.
Thesevalves are factoryset atthefollowing pressures:
-1
st stagesafety valve:8 bar;
-2
nd stagesafety valve:50 bar;
-3
rd stagesafety orfinalvalve: 225bar -or 330bar.
WARNING
Under no circumstances may these valves be adjusted to increase the calibrated pressure.If these
valves blow, check the cause that has led to the maximum pressure and take steps according to the
instructionsgiven inparagraph 12.1.Any tamperingwith thesafetyvalvescausesserious damageand
animmediate cancellationof theguarantee.
2.2.4 Lubricating unit - High pressure compressor
Lubricationiscarriedoutbymeansofapinscrewed
into the end part of the 2nd and 3rd stages
connectingrods (Fig. 9).
The 3rd high pressure stage is lubricated by oil
vapours.
9
2.2.3 Safety valves - High pressure compressor
2.2.2 Valve head unit (Fig. 8) - High pressure compressor
8

15
2.2.6
Cooling pipes (Fig. 10) - High pressure compressor
The cooling pipes between the 1st and 2nd stage,
betweenthe2nd and3rd stageandafterthe3rd stage
are made of stainless steel, like those for the
passageofairbetweentheseparator andthefilter.
10
This valve is fitted after the final filter. Just a few seconds after the compressor has been started up, it
keepsthe pressureofthe entiresystemat100± 20bar(see explodedviewChapter15),for thepurpose
of eliminating as much water as possible from the air. It also acts as a non-return valve.
2.2.5
Pressure maintenance valve - High pressure compressor
Technical description
2.2.7
Filters - High pressure compressor
11
INTAKE FILTER (Fig. 11)
Theintake filter iscoupled directlytothe lidof the
1st stagehead.
Theintake filterconsistsofacylindrical aluminium
casing provided with a screw cap that holds the
filteringcartridge.
A special attachment is provided on the filter for
the connection of an extension (optional) which
enablesair to betaken fromthe outsidewhen the
compressor is installed in a place without ideal
ventilation.
For the compressor to operate properly, the filter
maintenance must be carried out as provided for
andat theintervals recommended(instructions in
paragraph11.6).

16 Technical description
ACTIVATED CARBON FILTERAND MOLECULAR SIEVE(Fig. 12)
The filter consists of an aluminium tube (B) that
holdsthe filter cartridge(A).
The shell of the cartridge contains the activated
carbon (C) and the molecular sieve (D) placed
between felt disks.
The condition of the cartridge is of fundamental
importanceforthe qualityoftheair (seeparagraph
11.7for replacementinstructions).
12
2.2.8 Pilot valves - Low pressure compressor
13a
ThePilot Valve isdesigned toact asan automatic
“on”and “off”airswitch. Whenin the“on” position
itallows airto flowfromthe tankthrough theValve
to some device such as a compressor suction
unloader, thusactuating it.
Inthe “off”position (Fig.13a). this valvestops the
flowofairthroughthevalveandreleasethepressure
in the line to the device.
ThePilotValve worksasfollows: Tankair pressure
actsonthe bottomof thevalve.
Whenpressureisgreatenoughtoovercomespring
force holding valve down on lower seat, it lifts off
seat and allows air to flow around valve and out
throughside openingin PilotValve.
Whenpressure intank andon valvedrops, spring
forcesvalve backdown onlower seat.
SENSINGTUBE FROM
AIRRECEIVER
ACTUATING TUBE TO
HEADUNLOADER
MTG
THREAD

17
2.2.9
Frame and sound-proofed casing
13
The compressor and the electric motor are fitted
on a welded steel frame coated in epoxy resins
and are enclosed within a sound-proofed casing
coveredin sound-deadening,water-repellent and
fireproofpanels(Fig.13).
Theexcellentway inwhich the flowof thecooling
air has been designed enables the temperature
inside to be just slightly higher than the outside
temperature.
2.3
Machine control
14
Themachine functioncontrols arelocatedon an
electric control panel (Fig. 14).
Apartfrom thevariouscontrol buttons,thispanel
also includes an hour counter that enables the
number of machine operating hours to be
memorized.
The same controls are doubled up on two
independent control panels which each control
oneofthetwopumpunitspresentinsidethefilling
station.
Technical description
Airin lineto devicebeingactuated canthen escapethroughupperseatand outvent hole.Thepressure
atwhich thePilot Valve is“on” or“off”iscontrolled bythespring whichhas beeninstalled atthe factory.
A small adjustment can be made in the field by changing the spring force by compressing the spring
more or less with the adjusting screw provided by the Pilot Valve.

18
3.1.1 Sizes and weights (Fig. 15)
Technical characteristics
Thischapterprovides sometechnical information concerningthe machine.
3.1 Technical characteristics of the pump unit....................................................................... 18
3.1.1 Sizes and weights ..................................................................................................... 18
3.1.2 Machine series MCH 14 TECH NITROX .................................................................... 19
3.2 Noiselevel .......................................................................................................................... 20
Thepump unitconsistsof: threecompression stages,three cylinders,forced aircooling bymeansof a
large diameter fan, splash lubrication with immersed pins, stainless steel cooling pipes.
TECHNICAL CHARACTERISTIC
3
3.1 Technical characteristics of the pump unit -
low anf high pressure compressor
15

19
Technical characteristics
3.1.2
Machine series MCH 14 TECH NITROX
Table 1
* Membraneinput pressureregulated tobalance compressorrequirements.
High pressure compressor:
Maximum Block Output Pressure 300 bar - 4700 psi
Final System Discharge Pressure 225 bar - 3200 psi
Number of Stages 3
Number of Cylinders 3
Capacity ca 230 Lt/min. 14 m3/h5 - 8.0 SCFM
Lubricant Synthetic Nitrox
Condensate Drains 2 manual
1 automatic
Max. non-continuous peak pressure for NITROX 225 o 330 bar - 3200 o 4700 psi
Max. non-continuous peak pressure for AIR
Cylinder diameter 95/38/14 mm
Speed of rotation 1350 r.p.m.
Piston stroke 40 mm
Intermediate pressures 1° stage : 5 bar/70 psig
2° stage : 40 bar/570 psig
3° stage : 225-330 bar/3200-4800 psig
Power motor 2x5,5Kw-7,5HP
Tension and frequency (three-phase)
400V - 50Hz
440V - 60Hz
230V - 50Hz
230V - 60Hz
Membrane Operating Temperature Range 38-46 °C - 100-115 Fahrenheit
Input Operating Pressure Range Air UNIEN 132 -
DIN 3188 - CGA/E
Input Gas Composition 14 - 28 m3/h
Output Gas Composition Nitrox: 26% - 40% - air
Output Gas Volume (Stabilized): @ 32% - 40% (5-10 SCFM ) - 9-18 m3/h
Membrane Operating Temperature Range max 200psi - 14 bar
Low pressure compressor:
Maximum Block Output Pressure 13 bar
Number of Stages 2
Number of Cylinders 2
Capacity 23.5 SCFM - 40 m3/h
Tension and frequency (three-phase)
400V - 50Hz
440V - 60Hz
230V - 50Hz
230V - 60Hz
Lubricant Synthetic Nitrox
Condensate Drains 1 manuale
1 automatic

20
3.2 Noise level
TheMCH 14 TECH NITROX seriesof compressorshave beendesigned andbuilt withtheobjective of
reducing acoutsic pressure to a minimum.
Wheneverthemachinesareused inenvironments wherethedailynoiseleveltowhich theoperatorsare
exposedis higherthan 80dBA,theemployermust takesteps toapply allthemeasurements necessary
tosafeguard the operator’s health.In particular, theoperators must,ifnecessary, useall theindividual
protectiondevices toprotect themselvesfrom thenoise level.
Thereading ofthe machinenoise levelwas taken
fromthe “operator’swork place”(Fig.16),withthe
followingmethods andresults
16
Table 2
Technical characteristics
METHODS OF MEASUREMENT
ISO 3746
MCH 14 TECH NITROX
Level of acoustic pressure at the operator’s work place
Level of acoustic power
Peak level
dB(A) 75
dB(A) 97,1
-
INSTRUMENTS
Bruel & Kjacr sound level integrating meter
Microphone for sound level meter
Gauge
Mod. 2231 cl. 1
Mod. 4155 cl. 1
Mod. 4230 cl. 2