Casella CEL Thermohygrograph deluxe User Manual

THERMOHYGROGRAPH deluxe
User Manual

THERMOHYGROGRAPH

COPYRIGHT

June 2000

deluxe

User Manual

HB 3143-02

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

3.3 Setting 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

Page 2 of 12

THERMOHYGROGRAPH deluxe
User Manual

Introduction

1. INTRODUCTION

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

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.

deluxe

THERMOHYGROGRAPH.

The THERMOHYGROGRAPH
calibration certificate.

deluxe

model may be ordered with or without a

Page 3 of 12

Principle

THERMOHYGROGRAPH deluxe

User Manual

2 PRINCIPLE OF OPERATION

2.1 Humidity 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.

2.2 Temperature 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.

2.3 General

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
this can be set to cover two alternative ranges: -10oC to +40oCor0oCto

o

+50

C.

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

Page 4 of 12

deluxe

o

C to +50oC.

is 50oC, and