575A Portable Oxygen Analyser

Instruction Manual

Ref No. 00575/001A/0Order as Part No : 00575 001A

I

GENERAL SAFETY INFORMATION

Servomex Oxygen Analysers are sophisticated devices intended for use by qualified personnel only. Itis necessary that this manual be read and understood by those who will install, use and maintain thisequipment.

DESCRIPTION OF SAFETY TERMS IN THIS MANUAL

DANGER - Used when there is a possibility of serious personal injuryor death.

WARNING - Used when there is a possibility of personal injury.

CAUTION - Used when there is a possibility of damage to theequipment.

NOTE - Used to alert the user to pertinent facts and conditions.

Oxygen USP Verification Measurements

Analysers used for Oxygen USP verification, must be set up inaccordance with Section 2.2 and calibrated and used in accordance withthe relevant part of Section 3.2

II

NOTES

The 575A portable paramagnetic oxygen analyser complies with the European Community“Electromagnetic Compatibility Directive” 89/336/EEC by the application of the following standards:

IEC 61326-1; 1997 (BS EN 61326-1: 1997) Emissions Class B

The mains powered transformer supplied with the 575A analyser complies with the EuropeanCommunity “Low Voltage Directive” 73/23/EEC.

The 575A portable analyser is excluded from the scope of the European Community “Low VoltageDirective” 73/23/EEC.

The 575A is CE marked for the European Community “Electromagnetic Compatibility Directive”89/336/EEC only.

III

LIST OF CONTENTS

Section Page

1 DESCRIPTION AND SPECIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3 Sampling System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.4 Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2 INITIAL SET-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2.1 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42.2 Calibration Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3 OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3.1 Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63.2 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63.2.1 Setting the Zero . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63.2.2 Setting the Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63.2.3 Calibration for Oxygen USP Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63.3 Taking the Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.4 Effect of background gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.5 Vent Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93.6 Routine Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4 REPAIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4.1 Servicing the Oxygen Transducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104.1.1 Replacement of Transducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104.1.2 Replacement of Measuring Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124.1.3 Adjusting the Transducer Zero . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144.1.4 Adjusting the Transducer Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144.2 Leak Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5 PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

5.1 Recommended Spares (minimum) List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175.2 Complete Spare List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

IV

LIST OF ILLUSTRATIONS

Figure Page

3.1 Analyser Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74.1.1 Replacement of Transducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114.1.2 Replacement of Transducer Measuring Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124.1.4 Adjusting the Transducer Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

1

SECTION 1. DESCRIPTION AND SPECIFICATION

1.1 General.

This manual describes the Servomex 575A Portable Oxygen Analyser used to determine theoxygen content of a gas sample in the range 0 to 100% O2.

A power supply/adaptor unit is supplied as standard.

A 4 ½ digit liquid crystal display indicates the oxygen content to 0.01% resolution and to 0.1%intrinsic error (accuracy)

WARNING

This analyser is not suitable for use in hazardous areas or formeasuring flammable sample gases.

Medical UsesThis analyser is not an approved medical device and is not approved

for use in direct patient monitoring.

1.2 Principles of Operation.

The 575A oxygen analyser measures the paramagnetic susceptibility of the sample gas bymeans of a magneto-dynamic type measuring cell.

Oxygen is virtually unique in being a paramagnetic gas, this means that it is attracted into amagnetic field. In the Servomex measuring cell the oxygen concentration is detected bymeans of a dumb-bell mounted on a torque suspension in a strong, non-linear magnetic field. The higher the concentration of oxygen the greater this dumb-bell is deflected from its restposition. This deflection is detected by an optical system and twin photocells connected to anamplifier. Around the dumb-bell is a coil of wire. A current is passed through this coil to returnthe dumb-bell to its original position. The current is measured and is proportional to theoxygen concentration.

2

1.3 Sampling System.

The sampling system of the analyser includes a combination filter/automatic flow controldevice, designed to keep a constant sample flow through the measuring cell under varyingsample input pressures, and to prevent the entrance of particulate matter into the measuringcell. Excess flow at the analyser inlet is vented to the by-pass vent at the rear of the analyser.

1.4 Specification.

General

Display: 4 ½ digit LCD reading 0.00 to 100.00% oxygen with over rangecapability.

Environmental Limits.

Operating ambient 0 to +50 °C (32 to 122 °F)temperature:

Storage Temp. Range: -20 to +60 °C (-4 to 140 °F)

Relative humidity: 5-80%, non-condensing.

Intrinsic Error (accuracy)

There are various effects that will influence the accuracy of the analysers as follows (typicalvalues):

Temperature: Effect at 0% O2: <0.03% O2 / °C.

Effect on span: <0.1% O2 / °C.

Over the temperature range 10 to 30 °C.

Pressure: Directly proportional. A change of 1% in barometric pressure will causea 1% change of reading.

Tilt: <0.1% O2/15 degrees from the horizontal

Repeatability: <0.1% O2.

Linearity: <0.1% O2.

3

Sample Requirements.

Condition: Clean, dry gas with dew point 10°C (18°F) below ambient temperature.

Pressure: Minimum inlet 0.5 psiMaximum inlet 10 psi

Note: Deviation of <0.1% O2 over specified sample pressure range.

Flow rate: 1 to 6 l/min approx for inlet pressures from 0.5 to 10 psi.

Response time T90: Less than 7.5 seconds at a sample pressure of 10 psi.

Materials in contactwith sample: Stainless steel

VitonGlassPlatinumPolypropyleneGlass fibre filter

Physical Characteristics.

Case classification: IP40

Dimensions: Width 158mm (6.2 in)Height 186mm (7.3 in)Length 305mm (12.0 in)

324mm (13.0 in) including sample connectors

Weight: 2.8kg (6.16 lbs)

Gas connections: 6.3mm (1/4 in) ID tube, push-on.

Electrical.

Power supply unit: 230V ac ±15%, 48-62 Hz, with UK moulded plug.120V ac ±15%, 48-62 Hz, with US moulded plug.230V ac ±15%, 48-62 Hz, with European moulded plug.

Automobile cigar lighter adaptor: Universal 12V dc, 3A fused plug, with 2.1mm Jackplug.

4

NOTES

5

SECTION 2. INITIAL SET-UP

2.1 Power Supply.

A power supply unit for nominal 120V ac or 230V ac (±15%), 48 to 62 Hz is supplied. Alwayscheck that the voltage rating on the unit corresponds with your local electrical supply voltage.

A fused automobile lighter adaptor unit for a negative earth 12V dc automobile supply is alsoavailable.Always check that the adaptor is fully inserted into the lighter socket and that the LED is lit.

2.2 Calibration Gases.

The following calibration gases must be available:-

(a) Oxygen-free Nitrogen - Zero Gas

The minimum purity of this nitrogen must be 99.9%

When the 575A is used for medical oxygen testing, this must be a certified standardaccompanied by its certificate of analysis.

WARNINGNITROGEN IS AN ASPHYXIANT AND MUST NOT BE USED IN

CONFINED SPACES WITHOUT ADEQUATE VENTILATION.

(b) Instrument Quality Air

Instrument quality air meeting the requirements of ISA Standard S-7.3

- Dew Point Temperature: 10°C (18°F) below the lowest expected ambient temperature.

- Particle size: (maximum) <3 micron.

- Oil Vapour: <1ppm.

WARNING

NEVER USE THE ANALYSER TO MEASURE A GAS WITH A HIGHOXYGEN CONTENT FOLLOWING USE ON AIR WITH AN OIL VAPOURCONTENT EXCEEDING THE ABOVE STANDARD. THE OIL VAPOURWILL CONTAMINATE THE TUBING AND MAY RESULT IN A FIRE ONCONTACT WITH HIGH OXYGEN LEVELS.

If instrument quality air is not available, either dry bottled air or ambient air with optional handaspirator and drying tube may be used.

6

CAUTION

All gas cylinders used in conjunction with 575A Analysers must be fittedwith a regulator whose delivery pressure can be limited to between 0.5and 10 psig (70 kPa) and an appropriate output pressure gauge. This willprevent serious over-pressuring of the analyser and resulting damage tothe measuring cell. Adjustable filter flow regulators can deliver excessivepressures and cause analyser damage if the analyser vent is restricted.

c) Certified Oxygen Cylinder

A certified cylinder of high purity oxygen 99.2% minimum, for analyser span when verifyinghigh purity oxygen. The cylinder must be fitted with either a pressure regulator with gauge or anadjustable litre flow regulator. Use of high purity oxygen for span gas negates the requirementdor either instrument air or dried ambient air in (b).

WARNING

PURE OXYGEN REPRESENTS A POTENTIAL FIRE HAZARD ANDMUST BE HANDLED ACCORDINGLY.

7

SECTION 3. OPERATION

3.1 Controls.

Refer to figure 3.1

The analyser is live whenever power is applied to the rear power socket (no on/off switch).

Remove the protective plastic caps from the gas inlet, cell outlet and bypass outlet connectors.

3.2 Calibration.

Refer to figure 3.1

3.2.1 Setting the Zero.

Introduce zero gas (normally high purity nitrogen) at a pressure between 0.5 to 10 psig to thegas inlet on the front panel. Adjust the zero control on the front panel to give an indication of00.00 on the display. If the range of zero adjustment is inadequate then refer to section 4.1.3.for setting transducer coarse zero.

3.2.2 Setting the Span.

Introduce span gas - see Section 2.2(b) and (c), at a pressure between 0.5 to 10 psig to thegas inlet on the front panel. Adjust the span control on the front panel to give an indication onthe display within 0.01% of the span gas oxygen concentration.

When using clean dry air as the span gas, set the display to read 20.95%

When the oxygen content of the measured sample gas is above 21%, high purity oxygen isnormally used to set the analyser span. Set the span control so that the digital display readsthe known concentration of the span gas.

If the range of span adjustment of the span control is inadequate, the transducer coarse spanmay need adjustment. Refer to section 4.1.4.

3.2.3 Calibration for Oxygen USP Verification

In accordance with Title 21, section 211.194(c) of the Code of Federal Regulations, allcalibration standards must be accompanied by their manufacturer’s Certificate of Analysis(COA). The analyser zero gas must be 99.9% (minimum) nitrogen and the analyser span gasmust be 99.2% (minimum) oxygen. A drying tube is not required since the zero, span, andsample gases are all clean, dry cylinder gases. The sample filter may be checked quarterly.There are no requirements to have instrument quality air on hand.

8

Figure 3.1 Analyser Controls

9

3.3 Taking a reading.

After calibration the analyser is ready for use. Connect the gas sample at a pressure of 0.5 to10 psig to the gas inlet on the front panel. After a few seconds the oxygen concentration of thesample is displayed on the front panel. Wait for the value to stabilize before taking the reading.

WARNINGThis analyser is not suitable for use in hazardous areas or for

measuring flammable sample gases.

For most accurate results, the analyser should be used at the same ambient temperature andpressure at which it was calibrated. It should not be used where there are high levels ofvibration.

Depending on the ambient conditions, it is not always necessary to re-calibrate the analyserhaving moved it from one location to another. (ie Room to room within the same building) Theanalyser will only need re-calibration if it is placed on a surface which would take it outside itsaccuracy/tilt specification. (<0.1% O2/15 degrees from the horizontal)

The silica gel drying agent supplied with the analyser will absorb moisture and possibly someof the background/carrier gas resulting in inaccurate oxygen readings. Select an alternativedrying agent or consult Servomex if these inaccuracies are unacceptable. A dryer is not usedwhen testing dry cylinder gases.

WARNING

Never use the analyser to measure a gas with a high oxygen contentfollowing use on air with an oil vapour content. The oil vapour willcontaminate the tubing and may result in a fire on contact with high

oxygen levels.

3.4 Effect of background gases.

The composition of the background gas in the sample may have a small effect on the oxygenreading. For an analyser zeroed with nitrogen and spanned with oxygen the cross sensitivityerrors resulting from 100% of some common gases are shown below:

Argon -0.2% Krypton -0.5%Carbon dioxide -0.3% Neon 0.2%Halothane -1.9% Nitrous oxide -0.2%Helium 0.3% Xenon -0.9%

The effect is directly proportional to the concentration of the gas in the sample being measuredand in most cases can be ignored. Values for other gases are listed in Servomex ApplicationsNote No. 7986-0073.

10

3.5 Vent pressure

The pressure at the analyser sample (lower) vent connection is the same as that in themeasuring cell. The analyser determines the partial pressure of oxygen. Barometric pressurechanges occurring since the last calibration will cause a proportional change in the oxygenreading. Tubing connected to the vent must be sized to avoid back pressure at the samplevent.

3.6 Routine maintenance.

The frequency of calibration required will depend upon the operating requirement for accuracyand upon environmental conditions. The following is a guide which may be modified in the lightof your particular operating experience.

Daily: Adjust the Span.

Weekly: Adjust the Zero then the Span.Check the filter if the analyser is in frequent use.Note: For transfilling applications using clean dry cylinder gases, the filter need onlybe checked every three months.The filter element is removed by unscrewing the large filter knob on the back panel ofthe analyser. Discard the old element if dirty or wet and fit a new filter element (partno. 2337-3608).

CAUTION

The analyser must not be operated without the filter elementin place since dust and other particulates in the sample willdamage the measuring cell.

11

SECTION 4. REPAIR

Note: Repair of the analyser should be done by qualified personnel who are familiar with goodworkshop practice.Certified factory training is available from Servomex.

Any spare parts which are used should be as specified by Servomex.

4.1 Servicing the Oxygen Transducer

Note: Due to the strong magnetic field which exists around the transducer it isadvisable to remove wrist watches if worn.

Prior to commencing make a visual check of the analyser and transducer. Repair any broken,disconnected or shorted wires and tubing.

4.1.1 Replacement of Transducer

Refer to figure 4.1.1

1. Remove top half of the analyser case by unscrewing the four socket screws. Refer tofigure 3.1.

2. Disconnect the sample connections to the cell either by removing the push-on tubingor by undoing the pipe connections. Make a note of their positions for re-assembly.

3. Disconnect the display PCB ribbon cable to the transducer.

4. Remove the oxygen transducer by unscrewing the 4 screws on the base plate, thenundo the 3 screws on the underside of the base plate.

5. Replacement of the new transducer is the reverse of the removal process.

6. Check the pipework and wiring, ensuring nothing has been trapped during re-assembly.

7. Check pipework is leak tight. See Section 4.2.

8. Calibrate the analyser as in Section 3.2.

12

Figure 4.1.1 Replacement of Transducer

13

4.1.2 Replacement of Measuring Cell.

Refer to figure 4.1.2

Note: Due to the strong magnetic field which exists around the transducer it isadvisable to remove wrist watches if worn.

1. Remove transducer as described in section 4.1.1

2. Unsolder the yellow and black wires from the front of the measuring cell.

3. Using an allen key loosen the cell locking clamp.

4. Holding the magnet frame firmly with one hand, grip the measuring cell by the sideswith the other hand and pull the cell clear of the pole pieces.

CAUTION

Do not pull the cell out by its pipe.

14

Figure 4.1.2 Replacement of Measuring Cell

5. Remove the connecting tubes from the cell. Note the orientation of the tubes as there-assembly will require the tube orientated to their original positions.

6. Replace the connecting tubes onto the new cell using the two 'O' ring seals supplied with the new cell. Tighten the gas connections not more than 3 flats (½ turn) beyondfinger tight.

7. Replacement is a reversal of the removal process.

8. Check the cell is refitted the correct way up. Insert cell as shown in Fig 4.2 withyellow spot at the top as shown.

9. Check the electrical connections on resoldering, ensuring the Yellow wire goes to thepin marked with a Yellow spot and the Black wire to the other pin. Take care not tooverheat the terminals.

10. Check the pipework and wiring, ensuring nothing has been trapped during re-assembly.

11. Check pipework is leak tight. See Section 4.4.

12. Reset the coarse zero. See Section 4.1.5.

13. Calibrate the analyser as in Section 3.2

15

4.1.3 Adjusting the Transducer Zero

The 575 analyser uses a transducer with a large zero adjustment. If the front panel zerocannot achieve a display zero reading the analyser or transducer will need servicing orreplacement.

4.1.4 Adjusting the Transducer Span

Refer to figure 4.1.4

It may be necessary to adjust the Span of the transducer if the altitude at use is greater thanabout 1200m (4000ft) above sea level. It may also be necessary after fitting a new measuringcell.

1. Remove top section of case to gain access to the transducer adjustments. (Refer tofigure 3.1)

2. Check that the TRANSDUCER FINE SPAN is fully clockwise. The potentiometer will‘click’ when it reaches the end. (Note that the default position for this should alreadybe fully clockwise - for new transducers)

3. Adjust the FRONT PANEL SPAN fully clockwise.

4. Connect air (or oxygen) to the gas inlet at a pressure of less than 2psig.

5. Adjust the TRANSDUCER COARSE SPAN so that the front panel displays a nominal120% of air, approx. 25.14% O2 (or 120% of pure oxygen, approx. 120.00% O2)

6. Finally, adjust the FRONT PANEL SPAN to display to correct air, 20.95% O2 (oroxygen 100.00% O2) measurement.

7. Reassemble analyser and calibrate analyser to section 3.2

16

Figure 4.1.4 Adjusting Transducer Span

17

4.2 Leak Testing

Refer to figure 3.1

1. Connect together the 'Bypass' and 'Sample Out' gas connections on the rear of theanalyser and connect a water manometer to the sample 'In' gas connection on thefront panel.

2. Pressurize the sample system to 500mm Water Gauge and measure the leak rate onthe manometer. It should be less than 1mm/2min.

3. If leak rate exceeds the above value then check analyser pipework for leaks using asoap solution. This testing should also include the cell fitting and window.

4. Rectify leaks and recheck, and remove all residual soap solution.

18

NOTES

19

SECTION 5. PARTS LIST

The headings are:

Item: Reference list.

Description: The description is that of the item identified by the Part Number.

Part number: This is the number to quote when ordering a replacement. It describescompletely the item as set out in description.

The spare parts listed in the next section may be ordered from your nearest Servomex salesoffice. Please see the rear page of this manual for contact details.

5.1 Recommended Spares (minimum) List.

The list is a recommendation of minimum spares to keep on site. Your requirement for spare partswill depend upon your reliance upon the analyser, and the time required to order and receive sparesfrom your nearest Servomex spares offices.

Item Description Spare Part Number Quantity

6 Oxygen transducer tube ‘o’ rings 2323-1014 2

8 Automatic flow control device filters 2377-3608 4

12 Zero or Span potentiometers 10K/10T 2726-4133 1

21 Automobile lighter adaptor 3A fuse 2531-8917 3

20

5.2 Complete Spares List.

Item Description Spare Part Number

1 Case and rear panel assembly 00575991

2 Front panel assembly 00575992

3 Display PCB 00575901

4 Oxygen transducer assembly 01158000

5 Oxygen transducer cell 00325000

6 Oxygen transducer tube ‘o’ rings 2323-1014

7 Automatic flow control device 00570915A

8 Automatic flow control device filters 2377-3608

9 Gas connector 6mm 00570448

10 Gas connector 3mm 00570427

11 Power socket 2.1mm 2535-1143

12 Zero or Span potentiometers 10K/10T 2726-4133

13 Upper case moulding 3912-2409

14 Lower case moulding 3912-2416

15 Viton tube 2.2mm ID 1817-6012

16 Viton tube 5mm ID 1817-6029

17 230V ac with UK plug 2821-4597

18 120V ac with US plug 2821-4605

19 230V ac with European plug 2821-4612

20 12V dc Automobile cigar lighter adaptor 00575994

21 Automobile lighter adaptor 3A fuse 2531-8917

22 Hand aspirator 2387-0514

23 Drying tube 00101901

24 Instruction manual - English only 00575001A

21

NOTES

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NOTES