VQ1 Combustible Gas Detector Elements To be read in conjunction withIntroduction to Pellistor Gas MARKING Sensor and Pellistor Application Notes 1, 2, 3, 4, 6 and 7. Each element carries a serial number sleeve, fitted to one of the flexible leads. The number is in standard colour code (see INTRODUCTION table), reading from the base towards the free end of the lead. The VQ1 consists of two matched elements which are used for ColourCode the detection of combustible gases, particularly methane in air Black 0 Yellow 4 Grey 8 mixtures in concentrations from 0.1% upwards. There is no Brown 1 Green 5 White 9 interference from water vapour or carbon dioxide. Using the Red 2 Blue 6 recommended bridge circuit (see below) and the mounting Orange 3 Violet 7 arrangement shown on page 2, the minimum sensitivity is 20 mV/% methane. The detector bead is dark in colour and has a red sleeve on the second lead. This sleeve carries a letter code which, together GENERAL DATA with the serial number, fully identifies a pair of elements. The compensator bead is white and carries a black sleeve on Electrical the second lead. The information given below relates to the VQ1operating in the recommended circuit shown. NOTES Operation (see note 1) ......... continuous 1. Operation may be under either direct flow or diffusion Bridge supply ........... 2.0+ 0.1 V conditions in appropriate mountings (see page 2). Bridge power consumption ....... 0.75 W max 2. With open-circuit conditions at the bridge output. Minimum sensitivity (see note 2) . 20 mV/% methane Linearity ......... linear up to 3% methane 3. The response time is a function of the type of mounting 1 1 Response time to register 1 /%ina2 / % 4 2 used. concentration (see notes 2 and 3) .... 2 seconds 4. If the VQ1 is exposed to greater than 5% methane Maximum methane concentration concentration, the calibration of the instrument should be (see note 4) .......... 10 % checked. 5. The elements are supplied as a matched pair with a Mechanical trimming resistor R of the correct value which is between Mounting.............. see page 2 39 and 120 O. The trimming resistor is to be connected Outline............... see page 2 across the compensator element as shown below. Shock test ....... 250g,5 blows in each plane 6. The elements must be protected from certain organic and Vibration test.... 20g,24 cycles from 100 to 3200 Hz silicone vapours by suitable filtering, and caution should be exercised when operating in close proximity to hot, oily machinery. BRIDGE CIRCUIT COMPENSATOR 2309C (BLACK SLEEVE) SEE R NOTE 5 27O 1kO 2V ZERO SET 27O DETECTOR (RED SLEEVE) OUTPUT SGX Sensortech(IS) Ltd Registered in England No.08067077 A1A-VQ1 Issue 4, March 2007OUTLINE (All dimensionswithoutlimits arenominal) 2311B F D Ref Inches Millimetres E 1B A 0.435+ 0.010 11.05+ 0.25 C B 0.240+ 0.010 6.10+ 0.25 C 0.140+ 0.005 3.56+ 0.13 D 2.500 min 63.5 min 1G 1A E 0.040 1.02 F 0.230+ 0.020 5.84+ 0.51 G 0.323 max 8.20 max H 0.375 9.53 J O-RING INSULATOR METAL J 0.060 1.52 FLANGE H SEE NOTE Millimetre dimensions have been derived from inches. Note No bends may be made in this length. RECOMMENDEDMOUNTING ARRANGEMENTS 2310C AA LEAKPROOF Ref Inches Millimetres JOINT AA 0.750 max 19.05 max AB 0.375+ 0.005 9.53+ 0.13 AC 0.328+ 0.005 8.33+ 0.13 AD 0.323 min 8.20 min AB AE 0.750 max 19.05 max AF 0.375+ 0.005 9.53+ 0.13 AG 0.323 min 8.20 min 60 MESH STAINLESS Millimetre dimensions have been derived from inches. 1AD STEEL GAUZE AC 3 FLOW RATE 500 cm /min AE AF FILTER PAPER AND 1AG 60 MESH STAINLESS STEEL GAUZE SGX Sensortech(IS) Ltd Registered in England No.08067077 A1A-VQ1 Issue 4, March 2007