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Mic EC-912 Instruction Manual

Smoke measuring equipment
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Document type
Instruction Manual
Document no.
B-281-0006-00
Date
8 December 2020
Instruction Manual for
Smoke Measuring Equipment
EC-912
force
FORCE Technology
Park Allé 345
2605 Brøndby
Danmark
forcetechnology.com
+45 43 25 00 00
info@forcetechnology.dk
forcetechnology.com

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  • Page 1 Document type Instruction Manual Document no. B-281-0006-00 Date 8 December 2020 Instruction Manual for Smoke Measuring Equipment EC-912 force FORCE Technology Park Allé 345 2605 Brøndby Danmark forcetechnology.com +45 43 25 00 00 info@forcetechnology.dk forcetechnology.com...

  • Page 2: Table Of Contents

    Preparation for use .....................10 Unpacking ......................10 Mains cord ......................10 Performance check using an Analog MIC Control Unit (AMCU) ......11 Performance check using an Intelligent MIC Control Unit (IMCU) .......11 Installation of Measuring Ionization Chamber (MIC) ...........13 Installation of Vacuum Pump (VP) ..............15 Installation of Control Cabinet (CC) ..............15...
  • Page 3 Intelligent MIC Control Unit (IMCU) ..............24 Maintenance and service ..............25 Periodic maintenance ..................25 Measuring Ionization Chamber (MIC) ..............25 Analog and Intelligent MIC Control Unit (AMCU and IMCU) .......27 Flow Control Unit (FCU) ..................27 Vacuum Pump (VP)....................28 Periodical calibration of the MIC .................29 Possible errors and hints ..................29...
  • Page 4 Flow Control Unit AMCU Analog MIC Control Unit IMCU Intelligent MIC Control Unit Control Cabinet Vacuum Pump Calibration Ground CH (C) Chamber Chamber, equilibrium input output C.W. Clockwise C.C.W. Counter clockwise Instruction Manual MIC type EC-912 Revision no.4 4 / 38...

  • Page 5: General Information

    Furthermore, the chamber is also specified in “ISO 7240-7 Fire detection and alarm systems” for point smoke detectors. The MIC instrument can be used alone or in combination with different types of optical smoke measuring equipment. CEN: European Committee for Standardization Underwriters Laboratories Inc.

  • Page 6: General Description

    (VP). The air passes the flow control unit (FCU) on its way from the MIC to the VP. In the FCU the air can be set to a flow rate with needle valve. An exchangeable filter is inserted before the flow meter in order to reduce smoke deposits in this instrument.

  • Page 7: Specifications

    System specifications Measuring accuracy: The overall measuring accuracy of the whole system is limited by the measuring accuracy of the MIC, which is better than ±4% of full scale reading (X = 1) for 0  X < 0.9. Mains supply: 115 to 230 Vrms, 50 to 60 Hz without switch-over.

  • Page 8: Analog Mic Control Unit (Amcu) Type Ec-912-20

    Measuring time delay   10 sec. where  is defined as the time from the moment when the MIC is subjected to a smoke step function to the moment when the output has reached 63% of its final value.

  • Page 9: Vacuum Pump (Vp), Thomas Vte 3, Type Ec-999-08

    Approx. 0.15 kW /h  58 l/min, 50 Hz Capacity: 3.5 m /h  70 l/min, 60 Hz 4.2 m Degree of protection: IP54 Weight: 6.5 kg To top of pipe branches Instruction Manual MIC type EC-912 Revision no.4 9 / 38...

  • Page 10: Installation

    Allen wrench, 1.5 mm metric P.V.C. hose (in the ordered length) Multicable (in the ordered length) Control Cabinet with Analog MIC Control Unit, type EC-912-20 or Intelligent MIC Control Unit, type EC-912-25) and Flow Control Unit, type EC-912-40. Mains cord with plug.

  • Page 11: Performance Check Using An Analog Mic Control Unit (Amcu)

    Check the performance of the smoke measuring equipment as follows: Interconnect the MIC and the Control Cabinet (CC) with the multicable, the MIC connectors have yellow insulation rings. Align the code marks and push the plug gently into the connector when fitting the cable.
  • Page 12 The Calibrate button should only be pressed, when the Measuring Ionization Chamber, MIC, is known to contain clean aerosol free air. When the calibration is done and the MIC system is ready for normal operation, the Last Calibrated time stamp is updated.

  • Page 13: Installation Of Measuring Ionization Chamber (Mic)

    Installation of Measuring Ionization Chamber (MIC) The MIC is intended for mounting on a plane surface (e.g. wall, ceiling, etc.) in the location in concern, as shown in Fig 2.2. A circular opening in the mounting surface 10-12 cm in diameter is adequate Keep a distance of min.
  • Page 14 MIC chamber mounting holes 4,5mm 152mm Fig. 2.3 MIC chamber mounting holes Instruction Manual MIC type EC-912 Revision no.4 14 / 38...

  • Page 15: Installation Of Vacuum Pump (Vp)

    Installation of Vacuum Pump (VP) The smoke measuring equipment EC-912 is delivered with a vane-type vacuum pump Thomas type VTE 3. The VTE 3 pump is quiet in operation (noise level 58 dBA with exhaust hose). The pump is provided with a factory-set bypass valve, which prevents damage in case the inlet is blocked.

  • Page 16: Operation

    X can be selected. CAL button: When the button is pressed indicator ON light up and the MIC is now ready for offset calibration by means of the offset trimmer. Instruction Manual MIC type EC-912 Revision no.4...

  • Page 17: Intelligent Mic Control Unit (Imcu)

    Rear panel (see Fig. A.1.4 in Annex 1) Air inlet: Pipe branch for hose to air outlet on MIC. Air outlet: Pipe branch for hose to air inlet on VP.

  • Page 18: Smoke Density Measurements

    Air hose between air outlet on MIC and air inlet on FCU. Air hose between air outlet on FCU and air inlet on VP. Multicable between MIC and the MIC connector on the rear of the CC. Cable to recorder from outputs at the rear of the CC (if used).
  • Page 19 Subject the MIC to the smoke exposure the density of which shall be measured. Subject the MIC to aerosol-free air and repeat point e) and f) before the next smoke density measurement. Also check the rate of air flow, point b).

  • Page 20: Theory Of Operation

    So, their contribution to the external current becomes negligible. Thus the external current is a function of the smoke particle density in the measuring volume. Instruction Manual MIC type EC-912 Revision no.4 20 / 38...

  • Page 21: Measuring Ionization Chamber (Mic)

    Measuring Ionization Chamber (MIC) Ionization chamber design The MIC has a parallel plate electrode configuration in which the radioactive source (Am 241) is part of one of the electrodes. This configuration provides a measuring volume in which the ionization is uniform and approx.

  • Page 22: Electronics For Impedance Transformation

    Fig. 4.2.2. The circuit converts the ionization current at a high impedance level to a proportional voltage at a low impedance level. So, the length of the connecting cable between the MIC and the CC becomes uncritical.

  • Page 23: Analog Mic Control Unit (Amcu)

    Analog MIC Control Unit (AMCU) The low impedance voltage from the MIC is first amplified 100 times by a differential amplifier. Then the voltage is inverted and the offset voltage set by the offset trimmer on the front of the MCU is added.

  • Page 24: Intelligent Mic Control Unit (Imcu)

    Fig. 4.2.3 Principle of AMCU analogue circuit Intelligent MIC Control Unit (IMCU) Please refer to separate IMCU user manual Instruction Manual MIC type EC-912 Revision no.4 24 / 38...

  • Page 25: Maintenance And Service

    The holder for the radioactive source may be unscrewed for cleaning, without dis-mounting other parts of the MIC, by loosening the locking screw (refer to Fig. A.1.2 in Annex 1) and unscrewing the source holder. Make sure that the serial number of the source corresponds to the ionization chamber (see note in Section 5.2).
  • Page 26 Allow the parts of the MIC to dry before assembling. Assembling: Be careful not to leave any fingerprints or other impurities on the internal parts of the MIC during assembling. Brand names: LEXAN, MAKROLON Instruction Manual MIC type EC-912 Revision no.4...

  • Page 27: Analog And Intelligent Mic Control Unit (Amcu And Imcu)

    Assemble the MIC by pressing down the housing and aligning the three distance pieces with the three holes in the housing and fasten the screws. Make sure that the alignment marks on the housing and mounting plate match. Screw the holder with radioactive source in the top of the housing and fasten the locking screw (Allen screw 1.5 mm, metric).

  • Page 28: Vacuum Pump (Vp)

    Vacuum Pump (VP) The Thomas type VTE 3 pump contains an inlet filter and rotor blades which should be checked regularly. The rotor blades may be replaced by new blades when necessary. Instruction Manual MIC type EC-912 Revision no.4 28 / 38...

  • Page 29: Periodical Calibration Of The Mic

    Before we deliver any MIC, the radioactive source is examined and checked for any leakage by executing a WIPE-test according to ISO 9978:1992, clause 5.3.1. The WIPE test of the radioactive source ensures that the MIC is safe to use for a period of up to 2 more years.

  • Page 30: Electrical Leakage

    The leakage current in the MIC is: The leakage current in the MIC should be less than 1 pA. If the leakage current in the MIC is greater than 1 pA the electrode assembly is probably covered with smoke de-posits and needs cleaning.

  • Page 31: Force Technology Contact Information

    FORCE Technology contact information If you need any assistance for calibration, spare parts or repair of your MIC, please contact: FORCE Technology Venlighedsvej 4 DK-2970 Hørsholm Denmark Tel. +45 72 19 40 00 e-mail: MICSales@forcetechnology.com WWW: http://MIC.madebydelta.com Instruction Manual MIC type EC-912 Revision no.4...

  • Page 32: References

    A. Scheidweiler, Cerberus AG: The ionization chamber as smoke-dependent resistance. A. Scheidweiler, Cerberus AG: Description of the Measuring Ionization Chamber (MIC). P.E. Burry: Standard Ionization Chambers. Tagungsbericht zum 7. internationalen Vortragsseminar über Probleme der automatischen Brandentdeckung, Aachen 5. und 6. März 1975.
  • Page 33 Figure A.1.1. Smoke measuring equipment EC-912 Measuring Ionization Chamber (MIC), type EC-912-10 Control Cabinet (CC), type EC-999-04 Analog MIC Control Unit (AMCU), type EC-912-20 or Intelligent MIC Control Unit (IMCU), type EC-912-25 Flow Control Unit (FCU) EC-912-40 Vacuum Pump, (VP) Thomas VTE 3, type EC-999-08 Instruction Manual MIC type EC-912 Revision no.4...
  • Page 34 Figure A.1.2. Measuring Ionization Chamber (MIC) EC-912-10 with chamber housing re-moved Measuring electrode Guard ring Wind shield Radioactive source holder Chamber housing Locking screw for radioactive source holder Distance pieces for chamber housing Holes for screws to distance pieces Instruction Manual MIC type EC-912 Revision no.4...
  • Page 35 Figure A.1.3. Analog MIC Control Unit (AMCU) type EC-912-20 a) 3.1 digit LCD display b) Mode selector button c) Mode indicators Uc and X d) Mode indicators Y and Y20 (not used) e) Calibration button f) Calibration relay ON indicator...
  • Page 36 Figure A.1.4. Intilligent MIC Control Unit (IMCU) type EC-912-25 a) LED “Power” The color of the LED is green under normal operation, red during power up and flashing red in case an error is detected. b) LED “Calibrating” The color of the LED is...
  • Page 37 Figure A.1.5. Flow control unit type EC-912-40 Flow meter needle valve Instruction Manual MIC type EC-912 Revision no.4 37 / 38...
  • Page 38 Analogue recorder output for chamber voltage Uc Analogue recorder output for smoke density X EMI filter with mains switch, mains socket and fuse holder Air inlet pipe branch for hose from MIC Finger screws for disassembling of filter unit Connector for multicable to MIC Instruction Manual MIC type EC-912 Revision no.4...

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