ß-Aerosolmonitor FHT 59 C

Transcription

1 Technical Specification ZT E

2 page 1/11 1. FHT 59C Moving Filter Aerosol Monitor 1.1 General The FHT 59 C is a unique moving filter aerosol monitor that can operate for one year or longer without an operator having to change the sample filter. Aerosol bound activity is collected on a moving filter tape and is simultaneously measured by the integrated detector. The detector, a proportional counter, measures both alpha and beta activity and applies the alpha/beta ratio technique to compensate for radon progeny collected on the filter. The moving filter mechanism is rugged and reliable and has proven performance in hundreds of installations worldwide. Filter tape advance can be controlled in a number of ways including when the pressure drop across the filter tape indicates high dust loading when a prescribed activity level is reached at a specified time interval If the filter tape is advanced once per day (which is equivalent to changing the filter in a fixed-filter monitor daily) then the FHT59C can operate for up to 3 years without changing the filter cartridge. Personnel exposure is greatly minimized. Measurement values are displayed both for the artificial beta activity concentration and the natural radon progeny. Two alarm thresholds are available on both measurement channels. 1.2 System Components The FHT 59 C aerosol monitor comprises the following components: particulate sampling unit with filter tape transport mechanics sealed proportional counter tube with lead shielding evaluation electronics with LC display and key panel 19" chassis 7U for all components (except pump) air flow gauge and control

3 page 2/ Features Automatic measurement of gross natural and artificial -aerosol activity Measuring range for artificial -aerosols app. 2 Bq/m³ Bq/m³ Automatic compensation of the natural activity concentration making use of the / -ratio method Monitoring function with fast alarming Extremely low cross sensitivity against ambient dose rate levels (app. 1 Bq( )/ Sv/h, related to Cs-137) 4 shielding of the detector and the particulate sampling chamber. Shielding thickness from above app. 1.5 cm, other directions 1 cm. Self control of the monitor with signalisation outputs Integrated software for the evaluation of all count rates 4 line LC display and 3 signalisation LED s Operation by 4 keys in menu technique Compact filter transport mechanics Air flow app. 2 m³/h by low-noise, low-maintenance rotary vane pump Interface for remote data transmission Analog outputs for activity and concentration Relays for alarm and error output to external signalisation units Long maintenance intervals by virtue of large reserve of filter tape Compact design in 19" chassis

4 page 3/ Detector Assembly The FHT 59 C aerosol monitor is fitted with a permanently filled proportional counter tube. The efficiency values of this detector related to 4 geometry (measured under operation conditions, distance source filter tape app. 7 mm, planchet source 16 mm in the particulate collection chamber) account to: radio nuclide [%] -channel [%] -channel -efficiency related to 90 Sr/ 90 Y -efficiency related to 241 Am The charge sensitive preamplifier has an integrated HV supply and a threshold amplifier. 1.5 Measuring Electronics The single board electronics of the FHT 59C is fitted with the following functional groups: Z80-processor for data acquisition and instrument control 64 Kbytes flash memory 8 Kbytes CMOS-RAM Battery buffer for the CMOS-RAM with voltage control 2 serial ports with RS232 interface Interface to LC display with keypad and LED s Hardware clock Analog inputs for the flow gauge Analog output for the artificial -activity concentration 3 status relays with protective circuits

5 page 4/11 Errors are indicated via the status word on the display and are output to a signalisation relay as collective error: break of filter tape - end of filter tape air flow below set minimum or pump failure error filter tape measuring head (no particulate sampling) detector fail rate Alarm limits can be set for each of the following values: artificial -activity on the filter artificial -activity concentration Passing through the limits is also indicated via the status word on the display and is output to a signalisation relay as a collective alarm. The status of the unit is signalled via 3 potential free relay contacts at the backplane of the monitor. Message Relay 0 Relay 1 Relay 2 Operational status Collective alarm Collective error 1.6 Set-up and Operation Software The measuring electronics comprises all functions and programs necessary for the monitoring operation. Hereby, the full operability of the monitor both in standalone and in network operation is achieved. Program modules for the following functions are included: start-up routines (setting of parameters) data acquisition and evaluation routines air flow measurement limit value control calibration measurement of background control of tape feed mechanics

6 page 5/11 STATUS: 0000 OPERATION ERROR: 00 CONCENTR: 1 Bq/m3 DISP BACK FORW Upon return of power the monitor starts up automatically. The root menu shown on the left appears. From here, the user can branch to any other function. CONCENTR: 1 Bq/m3 ART. ACT.: 2 Bq AIR FLOW: 1950 l/h BACK FORW The measured value menu displays the value of the artificial activity on the filter, the derived activity concentration and the related air flow. CALIBRATION EFFICIENCY BETA Eb1: 21 % DISP BACK FORW The calibration is also implemented as a menu-driven sequential procedure. Upon completion of all necessary steps of the calibration and the related operator feed back the resulting value of the efficiency is displayed and stored for future use. 1.7 Technical Data Measuring range for -aerosols: Activity: app. 2 Bq Concentration: app. 2 Bq/m³- 0, Bq/m³ h (1m³/h) Cross sensitivity against ambient doserate related to Cs-137 -background: Direction of incidence: from above: from above: from left/right: from below: < 1 s -1, at 100 nsv/h 0.25 s -1 /µsv/h 0.25 s -1 /µsv/h 0.15 s -1 /µsv/h 0.25 s -1 /µsv/h Detector: Detector size: permanently filled proportional counter tube 28 mm active detector window

7 page 6/11 Shielding thickness: Preamplifier: Electronics: COM1: COM2: Data protocol: lead 15 mm from above, other directions 10 mm charge sensitive detector coupling modular design for ease of replacement single board in SMD technology V24/RS232 serial interface 25 pin SUB-D socket V24/RS232 serial interface 9 pin SUB-D socket FAG/GEI-RS232 network protocol NetView compatible Address space: Relay outputs: Relay 0 Relay 1 Relay 2 Analog port: Particulate sampling unit: Criteria for filter feed: Duration of filter change: 3 ea for the signalisation to external alarm unit: - operational status - collective alarm - collective error max. load of relays: 60 V AC/DC, 0,5 A selectable assignment: natural -activity concentration or artificial -activity concentration or artificial -activity on filter linear scale, freely selectable output range 0/4-20 ma, 500 max. burden or 0/2-10 V 12 bit resolution, galvanically coupled filter tape mechanics with automatic programmable filter advance - exceeding the maximum filter activity - passing below the minimum air flow - exceeding the maximum pressure drop across filter - elapse of time cycle - absolute time The related operational parameters can be freely selected via menu. 120 sec. with no pump running update of background countrate

8 page 7/11 Cross sectional area of filter spot: app. 200 mm² Aerosol filter tape: 4 cm x 42 m; grade S; acc. to DIN 24184; step width 37 mm app filter spots per full tape length. (With a daily filter change a long term operation of 3 years is possible) Degree of retention: Air flow: Flow gauge: > % test aerosol with particle diameter < 1 µm > % radioactively induced aerosol < 0.3 µm non-regulated: app. 2 m³/h through fresh filter down to 1 m 3 /h through particulate loaded filter (app. 24 h) regulated: 1 m 3 /h independent of filter load orifice plate with differential pressure measurement measuring range 1-3 m 3 /h Ambient and operation temperature: - 5 C to + 50 C Sample air: - 5 C to + 45 C Pressure range of sample air: Pressure difference between sample and ambient air: Climatic conditions: Mains supply of monitor: Power consumption without pump: Power consumption of pump: 700 hpa to 1100 hpa < 200 hpa 10 to 95 % rel. moisture, non condensing VAC, 50/60 Hz 15 W approx. 200 W fitted with power cord and mating plug to be connected to the backplane of the monitor

9 page 8/11 Dimensions (without pump): width: 480 mm depth (incl. connectors): 480 mm height (7 U): 315 mm Installation in 19 rack: additionally 2 U: 89 mm Weight: Weight of pump: 26 kg (without pump) 5 kg 2. Pump Ref. no RPM regulated pump VT4.4, Controlled Air Flow Rotary vane pump fitted with a variable frequency converter. The pump frequency is set via the 0-10V output of the central unit. A PID control loop maintains a constant air flow at a growing pressure drop across the filter tape. Remark: This pump has to be used in conjunction with the PM-10 inlet necessitating a constant air flow to maintain its particulate transmission characteristics. Supply Voltage: Supply Current: Power consumption: Operating temperature: C Control voltage: V 230 VAC, switchable to 115 VAC 230 V: typical 0.2 A, max. 1A 115 V: typical 0.1A, max. 2A 0.2 kw 3. Sampling Inlets and Tubes Ref. no TSP Sampling Head, 1m 3 /h Non-fractionating inlet for the sampling of the total suspended particulate (TSP) in accordance with VDI guideline 2463, part 3. EU: ISO/CD inhalable convention

10 page 9/11 Ref. no PM-10A Inlet, 1 m 3 /h PM-10 size selective inlet for the sampling of the inhalable particulate fraction with a median of 10 m aerodynamic diameter. Remark: This inlet can only be used in conjunction with a flow controlled pump. USA: EPA equivalent method EU: ISO/CD thoracic convention Ref. no Adapter for PM-10 necessary to mount the PM-10 inlet to a sampling tube. Ref. no PM-2.5 Inlet, 1 m 3 /h PM-2.5 size selective inlet for the sampling of the respirable particulate fraction with a median of 2.5 m aerodynamic diameter. Only to be used as a second stage after a PM-10 inlet. EU: ISO/CD respirable convention Ref. no Sampling Tube, 3000 mm Ref. no Sampling Tube, 800 mm Ref. no Sampling Tube, 400 mm The sampling tubes are internally polished to minimize particulate loss due to surface roughness. Inner diameter: Outer diameter: 12 mm 16 mm Ref. no. P Hose Nipple with Lock Nut to connect a flexible sampling hose to the air inlet of the monitor. Inner diameter: Outer diameter: 12 mm 16 mm

11 page 10/11 4. Options Ref. no Bit I/O Extension Board fitted with 6 relays to signal the following events: Alarm ½ artificial -activity on filter Alarm ½ artificial -activity concentration Alarm natural -activity on filter Alarm natural -activity concentration The related alarm limits can be freely selected via menu. Ref. no RS485 Interface for fieldbus operation of the unit via COM1. Address space: Ref. no Filter Tape Printer Upon filter change, time and date are printed to the tape besides the particulate sampling spot. This facilitates keeping track of the sampling time for later laboratory analysis. 5. Reference Sources Ref. no. SM Reference Source Sr-90/Y-90, 1 kbq Ref. no. SM Reference Source Am-241, 1 kb Ref. no. P Source Holder

12 page 11/11 6. Consumables Ref. no. KT Glass Fiber Filter Tape GF 10 Technical data: 4 cm x 42 m; grade S; acc. to DIN 24184; step width 37 mm app filter spots per full tape length. (With a daily filter change a long term operation of 3 years is possible) Degree of retention: > % test aerosol with particle diameter < 1 µm > % radioactively induced aerosol < 0.3 µm Ref. no. KT Carbon Vanes (1 set = 5 pcs) The typical stand time of a set of carbon vanes accounts to one year of permanent operation. Ref. no. KT Pump protection filter

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