Michell Instruments PSD2, PSD4 Operating Manual

PSD2

Pressure Swing Dryer

User’s Manual

97031 Issue 13.1

September 2018

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Use this information when contacting Michell Instruments for service purposes.

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PSD2

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www.michell.com

This document is the property of Michell Instruments Ltd. and may not be copied or

otherwise reproduced, communicated in any way to third parties, nor stored in any Data

Processing System without the express written authorization of Michell Instruments Ltd.

PSD2 User’s Manual

Contents

Safety ................................................................................................................................ v

Electrical Safety ........................................................................................................... v

Pressure Safety ............................................................................................................ v

Toxic Materials ............................................................................................................. v

Repair and Maintenance ............................................................................................... v

Safety Conformity ........................................................................................................ v

Abbreviations ......................................................................................................................vi

Warnings ............................................................................................................................vi

1 INTRODUCTION ................................................................................................1

1.1 Overview ........................................................................................................... 1

1.2 Operating Principle .............................................................................................1

2 INSTALLATION ..................................................................................................2

2.1 Installing the Dryer ............................................................................................. 2

2.2 Electrical Connections .........................................................................................2

2.3 Gas Connections ................................................................................................. 2

3 OPERATION ......................................................................................................3

3.1 Operating the Dryer ............................................................................................ 3

4 MAINTENANCE ..................................................................................................4

4.1 Maintaining the Dryer ........................................................................................4

4.1.1 Desiccant Change .........................................................................................4

4.1.2 Adjusting the Purge Flow ............................................................................... 6

4.2 Fault Diagnosis ................................................................................................... 8

4.2.2 Flow, Pressure and Timing Calibration ............................................................8

Figures

Figure 1 System Layout Drawing ............................................................................13

Figure 2 Schematic Flow Drawing ...........................................................................14

Appendices

Appendix A Technical Speciﬁ cations ..............................................................................11

Appendix B System Drawings .......................................................................................13

B.1 System Layout Drawing ................................................................13

B.2 Schematic Flow Drawing ..............................................................14

Appendix C Quality, Recycling, Compliance & Warranty Information ................................16

Appendix D Return Document & Decontamination Declaration ........................................18

iv 97031 Issue 13, July 2018

PSD2 User’s Manual

Safety

The manufacturer has designed this equipment to be safe when operated using the procedures detailed in this manual. The user must not use this equipment for any other purpose than that stated. Do not apply values greater than the maximum value stated.

This manual contains operating and safety instructions, which must be followed to ensure the safe operation and to maintain the equipment in a safe condition. The safety instructions are either warnings or cautions issued to protect the user and the equipment from injury or damage. Use competent personnel using good engineering practice for all procedures in this manual.

Electrical Safety

The instrument is designed to be completely safe when used with options and accessories supplied by the manufacturer for use with the instrument.

Pressure Safety

DO NOT permit pressures greater than the safe working pressure to be applied to the instrument. The speciﬁ ed safe working pressure is 5 to 7 barg (70 to 100 psig).

Toxic Materials

The use of hazardous materials in the construction of this instrument has been minimized. During normal operation it is not possible for the user to come into contact with any hazardous substance which might be employed in the construction of the instrument. Care should, however, be exercised during maintenance and the disposal of certain parts.

Repair and Maintenance

The instrument must be maintained either by the manufacturer or an accredited service agent. Refer to www.michell.com for details of Michell Instruments’ worldwide ofﬁ ces contact information.

Safety Conformity

This product meets the essential protection requirements of the relevant EU directives. Further details of applied standards may be found in the product speciﬁ cation.

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Abbreviations

The following abbreviations are used in this manual:

AC alternating current atm pressure unit (atmosphere) bar pressure unit (=100 kP or 0.987 atm) °C degrees Celsius °F degrees Fahrenheit dp dew point kg kilogram Hz Hertz lb pound l/min liters per minute max maximum mm millimeter ppm

parts per million (by volume)

ppb

parts per billion (by volume)

scfh standard cubic feet per hour V Volts " inch(es) % percentage

PSD2 User’s Manual

Warnings

The following general warning listed below is applicable to this instrument. It is repeated in the text in the appropriate locations.

Where this hazard warning symbol appears in the following

sections it is used to indicate areas where potentially hazardous

operations need to be carried out.

vi 97031 Issue 13, July 2018

PSD2 User’s Manual

1 INTRODUCTION

1.1 Overview

The Michell PSD2 is a Pressure Swing Dryer in a compact rack mounting unit designed to remove moisture from compressed air down to trace levels of less than 1 part per million by volume.

The dryer operates by pressure swing regeneration of a desiccant column. Design is such that, with 2 columns operating in rotation, a constant ﬂ ow of very dry air (or other inert gas) can be produced for long periods without maintenance.

Heat is not supplied to the desiccant making the unit energy efﬁ cient and extremely reliable with the typical lifetime of the desiccant being 5 years.

1.2 Operating Principle

INTRODUCTION

The supply pressure is regulated by PR1, and indicated by either gauge PG1 or PG2, depending which column is active at that moment in time.

The gas then passes through the solenoid valves (SV1 & SV2), which direct it to the appropriate desiccant column (DC1 or DC2).

The desiccant columns are ﬁ lled with 4 Ångström molecular sieve. The column capacity is designed so that, as the molecular sieve absorbs water from the gas, the moisture content at the outlet of the cylinder is reduced to <1ppmV. This output is achievable regardless of the moisture content of the gas source. the only stipulation is that it must not contain liquid water.

The dried gas then passes through the non-return valve (NRV1) before reaching the outlet port.

The life expectancy of the molecular sieve is preserved by continual regeneration of the active column (purging of accumulated moisture). At the beginning of the regeneration cycle the bulk of the moisture is removed by rapidly reducing the pressure in the column, which desorbs moisture from the molecular sieve surface. Following this, the remainder of the moisture is removed by ﬂ owing a small proportion of the dried gas from the active column.

Once this cycle is complete, the system switches columns, and begins the cycle again. This regeneration process operates on 10 minute cycles, to provide uninterrupted dry gas output.

Michell Instruments 1

INSTALLATION

2 INSTALLATION

The PSD2 is supplied with a full accessory package. Please check that you have received all the items listed on the Packing Check List.

The factory set power supply voltage is indicated on the yellow label located on the rear panel of the unit. The power supply voltage setting cannot be changed by the user as this involves replacing internal electro-mechanical parts. Contact Michell Instruments’ Customer Service Department (contact details at www.michell.com) if a change is needed.

2.1 Installing the Dryer

The PSD2 requires an operating environment of 0 to +50°C (+32 to +122°F), 0 to 90% RH. Refer to Appendix B for outline dimensions.

The PSD2 case is designed for 19” 6U rack mounting. However, it can be used as a bench mounted device without any special preparation. When rack mounting, simply screw the unit front panel to the front of the rack using 4 M6 X 15mm screws and plastic inserts.

PSD2 User’s Manual

NOTE: A minimum depth behind the PSD2 front panel of 48cm (18.9”) is required for the unit, pipes and wiring.

2.2 Electrical Connections

Either 220/240 V AC, 50Hz or 100/20 V AC, 60Hz power supply is required to operate this instrument. Refer to the yellow label located on the rear panel of the unit for the correct supply voltage required.

The power supply connection is via the 3-pin IEC plug located on the rear panel of the unit. A 3-core power cable is provided, the free end of which should be wired to a suitable earthed plug or directly via a fused power spur.

Power cable conductors are colored according to the convention: Brown L (Live)

Blue N (Neutral) Green/yellow E (Earth)

2.3 Gas Connections

Gas connections are made via tube ﬁ ttings located on the rear panel of the unit marked ‘GAS INLET’ and ‘GAS OUTLET’.

The gas inlet connection is a Swagelok® stainless steel 6mm bulkhead union tube ﬁ tting. The gas outlet connection is a Swagelok® stainless steel 6mm bulkhead union face seal (VCR) ﬁ tting.

Ensure the supply inlet gas is of a suitable pressure - between 5.5 to 7 barg (80 to 100 psig), free of oil and at a dew point of typically <-40ºC (<-40ºF). If the supply inlet gas does not meet this requirement it will reduce the dryer’s efﬁ ciency and eventually lead to complete failure.

NOTE: An oil free compressor or bulk inert gas source must be used.

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