Valco Instruments Co. Inc. Pulsed Discharge Detector Model D-2-IM Instruction Manual D2-IM.p65 ©2011 9/11 Printed in USA Valco Instruments Co. Inc. Valco International 800 · 367 · 8424 sales 713 · 688 · 9345 tech 713 · 688 · 8106 fax valco@vici.com Schenkon, Switzerland Int + 41 · 41 · 925 · 6200 phone Int + 41 · 41 · 925 · 6201 fax info@vici.
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Table of Contents Introduction Description and Operating Principles .......................................................................................... 1 Safety Notes and Information ......................................................................................................... 2 Symbols Installation Category Safety Maintenance Components of the Detector System .......................................................................................... 4 Description of Controls ..............
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1 Introduction Description and Operating Principle The pulsed discharge detector Model D-2-IM is a universal helium photoionization detector optimized for trace level work with micropacked and capillary columns. A schematic representation is shown in Figure 1. As the name implies, a stable, low power, pulsed DC discharge in helium is utilized as the ionization source.
Introduction 2 The PDHID response is universal except for neon, which has an ionization potential of 21.56 eV. Since this potential is close to the energy of the He* metastable (19.8 eV) but greater than the photon energy from the He2 continuum, neon exhibits a low ionization efficiency and low detector response. (NOTE: Valco makes an enhanced mode detector for neon. Consult the factory for information.
Introduction 3 Safety This instrument has been designed and tested in accordance with the product safety standard, EN61010. It has left the factory in a safe condition. This instruction manual contains important information and warnings which must be followed by the user to insure safe operation and to retain the instrument in a safe condition. The case, chassis, and measuring terminals are connected to the protective earth contact of the mains inlet.
Introduction 4 Description Quantity Product number Detector cell, PDHID D2 Mini ionization 1 PD-D2-IM Pulse supply module 1 PD-M2 1 I-23477 1 PD-C2 Cable, computer (unattenuated) output 1 I-23136 Cable, recorder (attenuated) output 1 I-23483 Helium purifier, miniature version 1 HPM Helium purifier, standard 1 HP2 Instruction manual 1 MAN-PDD-M Fittings kit 1 PD-KIT-IM 1/16" gold-plated ferrule 5 ZF1GP 1/32" Vespel ferrule 5 ZF.
Introduction 5 TEMPERATURE control and indicator Sets the temperature (°C) of the detector heater block. The indicator is steadily on when maximum power is being applied to the heater, steadily off when no power is applied, and regularly blinking on/off when the set temperature has been established. Note that due to the fail-safe mechanism designed into the temperature controller, the heater will not operate if mains power is applied before the heater is connected or if the detector is too cold (< 0°C).
Introduction 6 MODE SWITCH 200 CURRENT SWITCH 16 32 64 128 256 4 512 1024 2 1 240 160 TEMPERATURE CONTROL RANGE SWITCH 8 280 120 PDECD 1X INCREASE 320 80 ATTENUATION CONTROL 360 40 400 DETECTOR TEMP. PDHID 10X DECREASE MODE RANGE CURRENT ATTENUATION TEMPERATURE INDICATOR DISCHARGE INDICATOR V ECD nA HID DISCHARGE SWITCH DISCHARGE ZERO PUSH BUTTON PULSED DISCHARGE CONTROLLER ZERO DISPLAY MAINS INPUT FUSE MAINS SWITCH VALCO INSTRUMENTS CO. INC.
Introduction 7 ATTENUATED OUTPUT connector Normally connected to a strip chart recorder. This output has an unattenuated range of 0 - 10V, and an internal signal reference (-) at zero volts. For best noise performance, the shield (earth) and signal reference (-) should not be connected together. The signal from this output is scaled by the attenuation factor set on the front panel. UNATTENUATED OUTPUT connector Normally connected to a data acquisition system or other recording means.
8 System Requirements Components Not Included with the Detector System • • • • Helium (99.999% purity) and other support gases Ultra high purity grade gas pressure regulator with stainless steel diaphragm Any special adapters required for connection to the gas regulator Flow measuring device System Purity Discharge/Carrier Gas Considerations The performance of the detector is adversely affected by the presence of any impurities in the gas streams (carrier, discharge, or dopant).
System Requirements 9 Specifications Mains (line): 115/230 V~50/60 Hz, 175 VA Fuse: 2 A, time-delay, 5 x 20 mm Pressure: 6.9 kPa (1 psi) operating, 6.9 MPa (1000 psi) max. working Max temperature: 400°C Heater power: 60 W max., 48 V, PWM Sensitivity 10X range: 1X range: 1.0 V/nA 0.1 V/nA ± 1%* Range 10X: 1X: 10 nA full-scale 100 nA full-scale* Noise 1X: 10X: 20 fA/√Hz (referred to the input), 0.1 - 10 Hz* 5 fA/√Hz (referred to the input), 0.
System Requirements 10 GC Column Selection To prevent detector contamination, we strongly recommend disconnecting the column from the detector during column bakeout procedures. The PD-D2-IM is optimized for micropacked (1/16" and smaller) and capillary /PLOT columns. The column tubing must be thoroughly cleaned and baked before the column is packed.
11 Installation The detector is usually mounted on top of the GC column oven. The cabling as supplied requires the discharge module to be located within 0.6 m (2') of the detector and the controller to be within 1 m (3.5') of the detector and discharge module. The power cord for the controller is 1.8 m (6') long, and the signal output cables (attenuated and unattenuated) are 1.2 m (4') long. General Precautions • Do not use plastic/polymer or copper tubes for gas handling and interconnectons.
Installation 12 Gas Connections Remember these three points discussed earlier: (1) all surfaces that contact the gas stream must be glass or stainless steel; (2) do not use copper tubing or brass fittings; and (3) all tubes must be thoroughly cleaned and baked before use. The installation instructions below assume that the detector discharge will be supplied from a nearby cylinder of helium of the proper purity. If your installation is different, you may need to modify the instructions appropriately.
Installation 13 CAUTION: Never use leak detecting fluids on any part of this system. Installing and Purging the Helium Purifier 1. If the pressure regulator has a 1/8" male cone-type outlet port, install the Valco 1/8" external to 1/16" internal reducer (EZR21); if it has a 1/4" male cone-type outlet port, install the Valco 1/4" external to 1/16" internal reducer (EZR41). For other regulator outlet fittings, a wide variety of Valco adapters are available. EZR21 2.
Installation 14 Connecting the Discharge Gas to the Detector 1. If you are supplying the GC from the helium purifier, use the Valco tee (ZT1). Otherwise, use one of the Valco 1/16" unions (ZU1) to connect the outlet tube of the purifier to the inlet of the supplied discharge gas restrictor (TGA-R-10F60P). 2. Connect the outlet end of the restrictor to a flow measuring device and adjust the helium pressure to obtain a flow of and ~10 mL/min for the PD-D2-IM. 3.
Installation 15 Electrical Connections CAUTION: Do not use a wrench to tighten the SMC connectors on the bias and electrometer cables. Connections should be fingertight only. 1. Referring to Figure 4 as necessary, connect the bias and electrometer cables as follows: the BIAS-B cable to the top electrode (closest to the discharge electrodes), the electrometer cable (ELECT) to the middle, and the BIAS-A cable to the bottom electrode. 2.
Installation 16 Initial Power-Up 1. If it is not already there, set the MODE switch on the front of the controller to PDHID. 2. Set the discharge gas flow as specified in on page 14 in the section entitled “Connecting the Discharge Gas to the Detector”. CAUTION: Always make sure that discharge gas is flowing before powering up the detector. 3. Apply power to the helium purifier. 4. Turn on the MAINS switch located on the back of the controller. 5.
Installation 17 From this point, the standing current should be observed and logged after any system change. In addition, logging the standing current (with and without the column) on a regular basis is an effective monitor of system integrity (leaktightness and cleanliness). We also recommend tracking the internal standard (quantity on column/area count) for sensitivity continuity.
18 Warranty This Limited Warranty gives the Buyer specific legal rights, and a Buyer may also have other rights that vary from state to state. For a period of 365 calendar days from the date of shipment, Valco Instruments Company, Inc. (hereinafter Seller) warrants the goods to be free from defect in material and workmanship to the original purchaser.
19 Detector Performance Log In addition to the occasions indicated in the Comments area of the table below, (see Initial Power-Up, page 16), the standing current should be observed and logged after any system change. Logging the standing current (with and without the column) on a regular basis is also an effective monitor of system integrity (leaktightness and cleanliness). To check sensitivity continuity, we recommend tracking the internal standard (quantity on column/area count).
