Casella CEL Thermohygrograph deluxe User Manual

THERMOHYGROGRAPH deluxe	June 2000
User Manual

THERMOHYGROGRAPH deluxe

User Manual

HB 3143-02

COPYRIGHT

The copyright in this document which contains information is vested in CASELLA CEL LIMITED. The contents of this document must not be used for purposes other than that for which it has been supplied or reproduced or disclosed wholly or in part without the prior written permission of

CASELLA CEL LIMITED

CASELLA CEL LIMITED

Regent House

Wolseley Road
Kempston
Bedford
MK42 7JY
Telephone:	[phone]
Fax:	[phone]
E-mail	[e-mail]
Web:	www.casella.co.uk

Contents	THERMOHYGROGRAPH deluxe
	User Manual

TABLE OF CONTENTS

CONTENTS . . . . . . . . . . . . . . . . PAGE

1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. PRINCIPLE OF OPERATION . . . . . . . . . . . . . . . . . . . . . 4

2.1 Humiditity Measurement . . . . . . . . . . . . . . . . . . 4

2.2 Temperature Measurement . . . . . . . . . . . . . . . . 4

2.3 General . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3. PREPARATION FOR USE . . . . . . . . . . . . . . . . . . . . . . 5

3.1 Removing/Replacing the Drum . . . . . . . . . . . . . . . 5

3.2 Fitting/Replacing the Battery. . . . . . . . . . . . . . . . . 5

3.3Setting the Clock speed. . . . . . . . . . . . . . . . . . . 5

3.4 Fitting/Replacing the Chart. . . . . . . . . . . . . . . . . . 6

3.5 Fitting/Replacing the Pens. . . . . . . . . . . . . . . . . . 6

4.	OPERATING THE INSTRUMENT . . . . . . . . . . . . . . . . . .		8
5.	MAINTENANCE & SPARES . . . . . . . . . . . . . . . . . . . . .		9
	5.1	Routine Care . . . . . . . . . . . . . . . . . . . . . . . .	9
	5.2	Quarz Clock . . . . . . . . . . . . . . . . . . . . . . . . .	9
	5.3	Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . .	9
	5.4	Service . . . . . . . . . . . . . . . . . . . . . . . . . . .	9
	5.5	Spare Parts. . . . . . . . . . . . . . . . . . . . . . . . .	10
6.	SPECIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . .		11

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THERMOHYGROGRAPH deluxe	Introduction
User Manual

1.INTRODUCTION

This handbook introduces you to the basic operation and features of the

CASELLA deluxe THERMOHYGROGRAPH.

Thermohygrographs are used to produce a continuous record of the variation of both the temperature and relative humidity of the atmosphere against time, by drawing coloured traces on a chart.

Variations in relative humidity can affect many manufacturing processes, storage of raw materials, weights of items such as wool, paper, tobacco, confectionery, and computer operation, as well as being an important factor in human comfort. Since temperature is often linked to changes in relative humidity, this instrument records both on a single chart.

The THERMOHYGROGRAPH deluxe model may be ordered with or without a calibration certificate.

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Principle	THERMOHYGROGRAPH deluxe
	User Manual

2 PRINCIPLE OF OPERATION

2.1Humidity Measurement

The element that senses relative humidity is made from several strands of specially treated human hair, which shorten as relative humidity decreases and lengthen as it increases. The relative humidity element is connected through a linkage to the pen arm so that changes are recorded as an ink line on the chart. The linkage is designed to give a near linear movement over most of the chart range.

2.2Temperature Measurement

The temperature element is a bi-metal coil that expands and contracts with changes in temperature, causing its free end to move. The free end is connected via a spindle to the pen arm so that changes are recorded on the chart.

2.3General

Relative humidity and temperature are recorded on the same chart, so to distinguish between the two traces, the temperature pen is red while the relative humidity pen is black.

To allow the pens to pass each other without colliding, the black relative humidity arm is shorter than the temperature arm, so that the two traces are displaced in time with respect to each other.

Fibre tipped pens are supplied which contain sufficient ink in the body to write for approximately 9 months. Replace the pen when the trace grows too faint to read.

Relative humidity is always scaled from 0 - 100%.

The temperature span for the THERMOHYGROGRAPH deluxe is 50oC, and this can be set to cover two alternative ranges: -10 oC to +40oC or 0oC to +50oC.

When the instrument is dispatched, a special chart is fitted that gives instructions for changing the temperature offset to match the range of the chart selected. The unit is factory calibrated for 0 oC to +50oC.

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