Michell Instruments SF52 User Manual

SF52 User’s Manual
Michell Instruments 7
OPERATION
3 OPERATION
Operation is very simple, assuming the following installation techniques are adhered to:
Sampling Hints
Be Sure the Sample is Representative of the Gas Under Test:
The sample point should be as close to the critical measurement point as possible. Also,
never sample from the bottom of a pipe as entrained liquids may be drawn into the
sensing element.
2
3
Figure 7
Installation Location
Minimize Dead Space in Sample Lines:
Dead space causes moisture entrapment points, increased system response times and
measurement errors, as a result of the trapped moisture being released into the passing
sample gas and causing an increase in partial vapor pressure.
Deadspace

Figure 8 Indication of Dead Space
Remove Any Particulate Matter or Oil from the Gas Sample:
Particulate matter may ‘blind’ the sensing element and reduce its response speed. If
particulate, such as degraded desiccant, pipe scale or rust is present in the sample gas,
use an in-line fi lter, as a minimum level of protection. For more demanding applications
Michell Instruments offers a range of sampling systems (for more information contact
www.michell.com).
Use High Quality Sample Tube and Fittings:
Michell Instruments recommends that, wherever possible, stainless steel tubing and
fi ttings should be used. This is particularly important at low dew points since other
materials have hygroscopic characteristics and adsorb moisture on the tube walls,
slowing down response and, in extreme circumstances, giving false readings. For
temporary applications, or where stainless steel tubing is not practical, use high quality
thick walled PTFE tubing.
Position Transmitter away from Heat Source:
It is recommended, as good instrumentation practice, that the transmitter is placed
away from any heat source to avoid adsorption/desorption.

Michell Instruments SF52 Specifications

General

Power Supply	12 to 28 V DC
Operating Temperature	-40 to +60°C
Protection Rating	IP65
Material	Stainless Steel
Output Signal	4-20 mA
Dew Point Range	-100 to +20 °C
Measurement Range	-100 to +20 °C (-148 to +68 °F) dew point 0 to 100 %RH

Summary

Introduction

SF52 Transmitter Features

Details the key features of the SF52 dew-point transmitter, including measurement range and output options.

Installation Procedures

Instrument Unpacking and Checks

Instructions for checking standard components included in the SF52 transmitter packaging.

Electrical Connections and Schematics

Diagrams showing voltage and mA 3-wire connections for the SF52 transmitter.

Transmitter Mounting Guidelines

Guidance on mounting the SF52 transmitter into sampling blocks or directly into pipes/ducts.

Sample Block Mounting

Procedure for installing the SF52 transmitter into an optional G 1/2" BSP sample block.

Direct Pipeline Mounting

Procedure for directly mounting the SF52 transmitter into a pipe or duct.

Operation and Usage

Sampling Best Practices

Recommendations for obtaining representative gas samples and minimizing measurement errors.

Maintenance and Calibration

Routine Calibration and Re-calibration

Information on routine re-calibration services and recommended intervals for the SF52.

Bonded Seal Replacement Procedure

Details on obtaining replacement bonded seals for the SF52 G1/2-BSP.

Technical Specifications (Appendix A)

Performance Metrics

Details on measurement range, accuracy, repeatability, and stability of the SF52.

Electrical and Mechanical Details

Information on output signal, supply voltage, housing, dimensions, and process connections.

Dimensional Drawings

Diagrams showing the physical dimensions of the SF52 transmitter and sample blocks.

Quality, Recycling, and Warranty (Appendix B)

Compliance Directives and Information

Overview of directives Michell Instruments complies with, including ATEX, RoHS2, and WEEE2.

Humidity Measurement Practices (Appendix C)

Relative Humidity Definition

Explains relative humidity and its common abbreviation RH.

General Measurement Recommendations

Practical advice for accurate humidity measurements and instrument care.

Sampling Environment and Material Guidelines

Guidelines for sampling environments, materials, and avoiding contamination.

Measurement Range Specific Advice

Specific advice for dew point and relative humidity measurements across different ranges.

Return and Decontamination (Appendix D)

Decontamination Certificate Process

Form for declaring the decontamination status of equipment before return or service.

EU Declaration of Conformity

Product Compliance Statement

Declaration stating SF52 compliance with EU directives and relevant standards.