SKC chek-mate User manual

www.skcltd.com
chek-mate Air Flowmeter
Operating Instructions
This manual covers the following models:
375-00205 / 375-0550

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Purchase Details and Service Record
Thank you for choosing an SKC product. Your purchase is covered by our warranty, details of which can
be found inside the rear cover of this manual.
Product Model Number Product Serial Number Date of Purchase
SKC recommends a minimum service interval of one year for this product. The first service is due one
year from the date of purchase, and then at yearly intervals on this date. However, it is the responsibility
of the user to perform a risk assessment to determine the necessary frequency of servicing that is
required.
Service Date Service Date Service Date
159
2 6 10
3 7 11
4 8 12
Please note that SKC Ltd is the only authorised service centre in the UK, guaranteeing you access
to the full range of genuine SKC replacement parts. For all other areas a full list of SKC-approved
distributors and service centres can be found at www.skcltd.com
SKC UK service centre - Tel: [phone] Fax: [phone] Email: [email protected]

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Contents
Specifications................................................................................................................2
Introduction to the chek-mate Flowmeter........................................................................4
General Information .......................................................................................................6
Diagram of the chek-mate Flowmeter .............................................................................8
Using the chek-mate Flowmeter ...................................................................................10
Battery Care................................................................................................................14
Calibration of the chek-mate Flowmeter........................................................................16
Notes..........................................................................................................................18
Warranty .....................................................................................................................20

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Specifications
Parameter Model 375-00205 Model 375-0550
Airflow range 20 ml/min to 500 ml/min 0.5 litre/min to 5.0 litre/min
Airflow display resolution < 100 ml/min : 0.01 ml/min
>= 100 ml/min : 0.1 ml/min 0.001 litre/min
Airflow accuracy
20 to 50 ml/min : ±2.5% of
reading
50 to 500 ml/min : ±1% of
reading
0.5 to 0.75 litre/min : ±2.5% of
reading
0.75 to 5.0 litre/min : ±1% of
reading
Weight 232 g (8.2 oz) 236 g (8.3 oz)
Operating temperature range 0 °C to 40 °C (32 °F to 104 °F)
Operating atmospheric
pressure range 700 mbar to 1090 mbar (20.7 inHg to 32.2 inHg)
Operating altitude Sea level to approximately 3050 m (10000 ft) above sea level
Enclosure IP rating IP40
Battery 9V alkaline disposable PP3 / 6LR61 / 1604A or equivalent, or
8.4V NiMH rechargeable PP3 / 6HR61 / 8.4H5 or equivalent
Automatic power off timer 15 minutes

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Specifications
83.5mm ( 3.3”) 33.5mm ( 1.3”)
178.5mm ( 7.1”)
Note:
SKC Ltd reserves the right to make changes to the specification and design of this product at any time
without prior notice to the end user.
The chek-mate flowmeter is manufactured by SKC Ltd under a sole license from Graham Blatchford.

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Introduction to the chek-mate Flowmeter
The chek-mate flowmeter is designed specifically for use in the occupational health and
safety industry for the purpose of calibrating the air flow rate into air sample trains. Its flow
range makes it suitable for use across a broad range of air sampling methods and with a
broad range of air samplers, sample media and air sample pumps.
Operating Principle
The chek-mate is an orifice type flowmeter. Its reading is determined by measuring the
pressure drop across the orifice caused by the flow of air through the orifice, using a
differential pressure sensor. This type of flowmeter gives a mass flow reading meaning
that the pressure drop across the orifice will be constant for a given mass flow of gas
independent of the density of the gas.
The chek-mate also incorporates an ambient temperature sensor and an atmospheric
pressure sensor and uses the readings of these sensors to correct the mass flow reading
generated by measuring the pressure drop across the orifice to the current ambient
temperature and atmospheric pressure. This correction provides an indicated flow reading
that is equivalent to a volumetric flow reading when the inlet of the flowmeter is open to
atmosphere.
CalChek Pump Calibration
The 375-0550 chek-mate model incorporates a CalChek serial interface which enables it to
communicate directly with SKC AirChek 2000, AirChek 3000 and AirChek Touch pumps, in

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Introduction to the chek-mate Flowmeter
order to perform automatic flow calibration of these pumps.
The chek-mate is connected to the pump using a CalChek communication cable (P/N 375-
200) which plugs into a socket on the right hand side of the chek-mate, and to the serial
interface port on the pump.
The chek-mate automatically outputs its flow rate reading via the CalChek serial interface at
3.5 second intervals when airflow through the chek-mate is present.
Refer also to the specific pump user manual for detailed instructions on performing CalChek
calibration.

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General Information
1) Care of the chek-mate Flowmeter
• Use only the specified disposable or rechargeable battery types.
• Ensure that discharged batteries are not left in the battery compartment for long periods
to prevent damage caused by electrolyte leakage.
• Avoid extended use of the flowmeter in areas with high levels of airborne particulates.
An external inlet filter (not SKC supply) can be used with the chek-mate flowmeter if
this cannot be avoided. Any filter used should have high collection efficiency (collect the
majority of all dust particles) and low back pressure.
• Ensure that fluids do not enter the flowmeter inlet or outlet ports.
• If the flowmeter has been stored in a cold location and is immediately taken to a hot,
humid location, do not use the flowmeter until it has stabilised to the higher ambient
temperature to prevent condensation forming inside the flowmeter.
• The flow meter case is IP40 rated: it is not rated as waterproof or splashproof and,
therefore, must not be used where it is possible for water to enter the casing.
• There are no user serviceable parts within chek-mate flowmeter. Opening of the chek-
mate case will void the product warranty and could affect the instrument calibration. An
anti-tamper warning label is fitted to the case which will identify that the case has opened.
Warning - Failure to follow these guidelines will void the product warranty.

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General Information
2) The WEEE Directive
This product is marked with the crossed out wheelie bin symbol, which identifies that it falls
within the scope of the European Directive 2002/96/EC on waste electrical and electronic
equipment (WEEE). At the end of it’s useful life, this product must be disposed of in an
environmentally sound way as detailed in the Directive. Note that the battery must be
separated from the product and disposed of as detailed in the Batteries Directive (see
below). Please contact your local distributor or SKC Ltd for further details on how to comply
with the requirements of the WEEE Directive. SKC Ltd’s producer registration number is
WEE/KH0054TQ.
3) The Batteries Directive
The alkaline disposable battery supplied with this flowmeter and any spare
batteries purchased for it, fall within the scope of the European Directive
2006/66/EC on batteries and accumulators and waste batteries and
accumulators. At the end of the battery’s life it must be disposed of in an
environmentally sound way as detailed in the Directive. Please contact
your local distributor or SKC Ltd for further details on how to comply with
the requirements of the Batteries Directive. SKC Ltd’s batteries producer
registration number is BPRN00454.

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2 1 5 4
367
8
Diagram of the chek-mate Flowmeter

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Key to Flowmeter Diagram
1. LCD screen
2. Low battery indicator
3. On/Off button
4. Inlet port
5. Outlet port
6. Battery compartment cover
7. Battery
8. CalChek interface socket (375-0550 model only)

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1) Setting an Air Sample Train Flow Rate
a. Ensure that the chek-mate flowmeter has been in the location where it is to be used for
enough time for its temperature to stabilise to the ambient temperature. A minimum of
10 minutes is recommended. Shield the flowmeter from exposure to direct sunlight to
prevent heating of the case by the sunlight.
b. Switch on the flowmeter by pressing the on/off button on the front. The LCD screen will
cycle through the startup messages ‘On’ followed by the flow meter range (‘0.5 L’ for the
375-00205 model and ‘5.0 L’ for the 375-0550 model), and will then indicate the current
flow rate or ‘- - - -’ if there is no airflow or the flow rate is below the minimum display
value. The minimum display value is dependent on the atmospheric conditions, but at
20 °C and 1013.25 mbar (1atm) the values are 5 ml/min for the 375-00205 model and
0.3 litre/min for the 375-0550 model. The minimum display value will be higher when the
chek-mate is used at higher altitudes and temperatures.
Note: The chek-mate flowmeter does not perform a zero of the flow reading at startup
therefore it is also possible to switch on the flowmeter with the air sample train already
connected and airflow passing through the flowmeter without affecting the accuracy of
the flow reading.
c. Connect the flowmeter outlet hosetail to the inlet of the air sample train using a length
of flexible tubing (1/4” or 6.5mm bore tubing is recommended) and calibration adapter
if required.
Using the chek-mate Flowmeter

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Using the chek-mate Flowmeter
d. Start the air sample pump and observe the reading of the flowmeter until it achieves
a steady value. The reading may fluctuate by a small amount either side of the steady
value (up to ±0.5 ml/min on the 375-00205 model and ± 0.005 litre/min on the 375-0550
model).
If the flow is fluctuating there are two suggested options to determine the average flow
value -
• Observe the highest and lowest readings and calculate the average of these two
readings, or
• Note 10 chek-mate readings and calculate the average of the 10 readings.
Note: It is recommended to allow the pump to run for a minimum of 5 minutes to
stabilise before adjusting the flow rate.
e. Adjust the air sample pump to give the desired sample airflow rate.
f. Disconnect the tubing from the flowmeter outlet hosetail taking care to pull the tubing
in line with the axis of the hosetail and not to twist the tubing. Switch off the flowmeter
using the on/off button.
2) Automatic Power Off Timer
The chek-mate flowmeter will remain on indefinitely provided that an airflow rate above the
minimum display value is indicated. With an airflow rate lower than the minimum display

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Using the chek-mate Flowmeter
value or no airflow (‘- - - -’ indicated on the screen) the flowmeter will automatically switch
off after 15 minutes to preserve battery power.
3) CalChek Flow Calibration
a. To perform automatic flow calibration of SKC AirChek 2000, AirChek 3000 and AirChek
Touch pumps using the 375-0550 chek-mate, the optional CalChek communication
cable (P/N 375-200) is required. Plug one end of the cable into the socket on the right
hand side of the chek-mate flowmeter and the other end of the cable into the serial
interface socket on the pump (the socket is mounted on the charging cradle for the
AirChek Touch pump and the pump must be fitted to the charging cradle to perform
CalChek calibration).
b. When performing a single point CalChek calibration of a complete sample train connect
the outlet port of the chek-mate to the inlet of the sample train (using a calibration
adapter if required).
c. A full CalChek calibration, which automatically calibrates the pump across its entire
operating range, is performed with no sample train connected between the chek-mate
and the pump. A pulsation dampener (P/N 375-100) is therefore required to be connected
in place of the sample train between the chek-mate outlet port and the pump inlet port.
d. The CalChek function is initiated on the pump. Refer to the specific pump users manual
for detailed instructions on this. When airflow through the chek-mate is detected the

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Using the chek-mate Flowmeter
chek-mate automatically outputs its flow readings via the CalChek interface at 3.5
second intervals.
e. The pump will automatically read in the chek-mate flow readings as required to complete
the CalChek process, and completion of the process will be indicated on the pump
display.

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Battery Care
• SKC recommends the use of quality alkaline primary (disposable) batteries to ensure
long battery life and prevent damage due to leaking battery electrolyte. A quality primary
battery such as the Duracell Industrial model supplied with the flowmeter should provide
as much as 30 hours of operation.
• When the battery voltage drops below 8V as it nears the end of its life, the flowmeter
LCD indicates ‘LOW BATTERY’. It is recommended to replace the battery at this point
to ensure uninterrupted use of the flowmeter. When the battery voltage drops further
to below 7V the LCD ‘LOW BATTERY’ indication will flash on/off and the flowmeter will
automatically switch off. If the flowmeter is switched on again with the battery in this
condition, the LCD will indicate ‘bAtt’ ‘LO’ ten times and then automatically switch off.
• To replace the battery, unfasten the two captive screws securing the battery compartment
cover using a Pozi-drive size 1 screwdriver and remove the battery compartment cover.
Lift the old battery straight up out of the battery compartment. Fit the replacement
battery ensuring the correct orientation of the terminals as detailed on the label at the
bottom of the battery compartment. Fit the battery compartment cover and secure with
the two captive screws taking care not to overtighten the screws.
• The SKC replacement primary (disposable) battery part number is P37500.
• NiMH secondary (rechargeable) batteries may also be used (not available from SKC), but
it must be ensured that the battery used is an 8.4V nominal type, and not a 7.2V nominal
type which are also manufactured.

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Battery Care
• The European Batteries Directive and equivalent legislation in other countries requires
that all batteries are disposed of correctly at the end of their working life. This means that
they must be collected and treated separately from other waste.
• It is recommended to remove the battery from the battery compartment if the flowmeter
is not to be used for an extended period of time. Deep discharge of alkaline batteries
can result in the eventual leakage of battery electrolyte even from quality batteries and
can cause corrosion of the battery compartment terminals and potentially the flowmeter
printed circuit board.

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Calibration Interval
SKC recommend a minimum calibration interval of one year for this product. However, it is
the responsibility of the user to determine the most suitable interval in order to meet their
quality assurance system requirements. Consideration should also be given to the frequency
of use and operating environment when determining the calibration interval.
Calibration Method
The chek-mate is primarily designed to perform flow calibration of air sample trains which
incorporate an air sample pump to provide the airflow, therefore the airflow is pulled through
the chek-mate by the vacuum generated by the air sample pump.
To ensure that the SKC factory flow calibration is representative of how the chek-mate
is actually used the flow calibration is performed under vacuum. Factory calibrations are
performed by applying the airflow alternately to the chek-mate and reference flowmeters.
SKC recommend that subsequent flow calibrations of the chek-mate flowmeter are also
performed under vacuum and applying the airflow alternately to the chek-mate and reference
flowmeters. However, positive pressure flow calibration using compressed laboratory air or
nitrogen gas is also acceptable, and series connection of the chek-mate and reference
flowmeters under either vacuum or positive pressure are also acceptable.
Calibration of the chek-mate Flowmeter

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Calibration of the chek-mate Flowmeter
Important notes for third party flow calibrations:
1. It is strongly recommended to send a copy of this instruction manual with the chek-mate
unit when sending to a third party calibration laboratory.
2. It is recommended to fit a new battery prior to sending the chek-mate for third party
calibration.
3. The chek-mate indicates air flow in ml/min on model 375-00205 and litre/min on model
375-0550, at the current ambient temperature and atmospheric pressure, therefore the
reference flow measurement must be corrected to these conditions for comparison with
the chek-mate indicated flow reading.
4. The factory flow calibration is performed under vacuum therefore the calibration gas
used is ambient air with relative humidity of 50% ±20% RH. When performing positive
pressure flow calibrations using compressed dry laboratory air or nitrogen gas, the
difference in gas density must be corrected for.
5. When performing flow calibration under vacuum with the chek-mate connected in series
with the reference flow meter the chek-mate should be connected with its inlet port open
to atmosphere.
6. When performing flow calibration under positive pressure with the chek-mate connected
in series with the reference flow meter the chek-mate should be connected with its outlet
port open to atmosphere.

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Notes