Rototherm CLEARSCAN RECORDER User Manual

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Rototherm CLEARSCAN RECORDER User Manual

user manual

installation, setup, operation & calibration

With over sixty years of experience, British Rototherm continues to be a world leader in the manufacture of industrial instrumentation for measuring, monitoring and controlling Temperature, Pressure, Humidity, Flow and Level.

British Rototherm products are manufactured in its modern factory located in the South Wales region of the United Kingdom. Sited on 6 acres of land at Kenfig Industrial Estate, the company operates from a modern 6,030 square metre (65,000 square feet) factory.

Suitable for many industrial applications, Rototherm products are precision built to the highest quality.

Approved by major companies and contractors in the United Kingdom and throughout the world for the supply of instrumentation and associated products, Rototherm products are specified and installed wherever reliability and long lasting, accurate performance is demanded.

Rototherm’s high quality and performance is guaranteed by an uncompromising approach to quality.

Rototherm is supported throughout the United Kingdom by Technical Representatives and by distributor/Stockists, who can be relied upon for support, technical advice and service.

Rototherm also has representation in many countries throughout the world where technical support and advice may be sought.

Other products in the Rototherm range of instrumentation include:

Mechanical Recorders & Recorder Controllers

Pneumatic Indicators & Recorder Controllers

Thermometers

Digital Thermometers

Pressure Gauges

Digital Pressure Gauges

Thermowells

Temperature Sensors & Assemblies

Orifice & Restriction Orifice Plates

Recorder Charts, Pens & Spares

Issue 1:2005

British Rototherm Company Limited

Kenfig Industrial Estate, Margam, Port Talbot, SA13 2PW United Kingdom

Telephone: +44 (0) 1656 740 551 Facsimile: +44 (0) 1656 745 915

E-mail: sales@rototherm.co.uk Web Site: www.rototherm.co.uk

ISO9001:2000

FM11958

In keeping with British Rototherm’s policy for contuned product development and improvement, we reserve the right to amend specifications without notice. © 2005 British Rototherm Co. Ltd. All rights reserved.

Trademarks: All brand names and product names used in this manual are trade names, service marks, trademarks or registered trademarks of their respective owners.

CONTENTS

Page

 

 

 

Introduction

2

Description of Operation of Gas Pressure Recorder

2

 

 

Description of Operation of Temperature Recorder

2

Description of Operation of Differential Pressure Recorder

2

 

 

Receipt of Recorder

3

Receipt of Temperature Recorder

3

 

 

Installation and Mounting - wall or panel mounting

3

Installation and Mounting - 2” pipe or post mounting

4

 

 

Installation and Mounting - Differential Pressure Recorder complete with 2” pipe or post mounting

5

Process Connections - Pressure

6

 

 

Process Connections - Temperature

6

Process Connections - Differential Pressure Recorder

7

 

 

Access to the Recorder

7

Internal Features

8

 

 

Recorder Start-up Check

8

Differential Pressure Recorder Initial Start-up

9

 

 

Differential Pressure Recorder General Practices

9

Fitting a Chart

9

 

 

Inking System

9

Replacement of Ink Pens

10

 

 

Pen Friction and Zero Adjustment

10

Tracking Adjustment to Chart Time Line

11

 

 

Chart Drives

11

Linkage and Pivot Attachments

11

 

 

Basic Fault Finding

13

Temperature Pen Calibration

18

 

 

Pressure Pen Calibration - for pressure ranges 2.5 bar to 40 bar

19

Pressure Pen Calibration - for pressure ranges 60 bar and above

19

 

 

Maintenance and Calibration - Differential Pressure Recorder

21

Calibration of Differential Pressure Pen

21

 

 

Spares List

23

Illustrations

 

 

 

Fig. 1a Outline Dimensions for 12 inch chart recorder (wall or panel mounting)

3

Fig. 1b Outline Dimensions for 12 inch chart recorder (2” pipe / post mounting)

4

 

 

Fig. 1c Outline Dimensions for 12 inch chart recorder (fitted with Differential Pressure Unit)

5

Fig. 1b Wall mounting dimensions using optional wall bracket kit

5

 

 

Fig. 2 Internal Features (with chart plate in place)

8

Fig. 3 Measuring and recording system details

10

 

 

Fig. 4 Linkage and pivot attachments

12

Fig. 5a Temperature recorder internal layout

14

 

 

Fig. 5b Pressure recorder internal layout (pressure ranges up to 40 bar)

15

Fig. 5c Pressure recorder internal layout (pressure ranges 60 bar and above)

16

 

 

Fig. 5d Differential pressure recorder internal layout

17

Fig. 6 Typical pressure calibration setup

20

Clearscan™ Recorder Series - Operating and Service Manual

INTRODUCTION

The Clearscan™ Series of circular chart recorders is designed to measure and record process variables such as temperature, pressure and flow.

A maximum of three measuring systems can be provided in each instrument, a fluid or gas expansion system is used for temperature recording, a bourdon tube or diaphragm/capsule for pressure measurement and a differential pressure cell for flow reading.

The measured values are continuously recorded on a calibrated circular chart of 12 inches nominal diameter, which is rotated at a constant speed by a chart drive mechanism.

DESCRIPTION OF OPERATION OF GAS PRESSURE RECORDER

On medium and high-pressure ranges, (i.e. approx. 2.5 bar to 2000 bar) pressure is applied at the recorder connection through capillary tubing to a spiral wound bourdon tube.

An increase in pressure partially uncoils the bourdon tube to which is fitted a take-off assembly arm converting the rotational movement into linear movement.

A horizontal adjustable linkage is pivoted from the take-off arm to a pen mechanism bracket, incorporating a pivot mounted onto an adjustable ratio post, locked into position on the pen bracket.

The ratio post provides span adjustment; it's position setting the pivot distance of the centre of rotation of the pen arm itself.

Adjusting the ratio post upwards nearer the centre of rotation increases the pen travel whilst conversely adjusting the ratio post downwards will result in less travel of the pen for the same amount of deflection from the bourdon tube

take-off arm.

The top of the pen bracket carries the pen arm mounted onto a separate adjustment plate which provides fine zero adjustment at the pen nib and adjustment to the amount of tension on the pen arm itself; thereby ensuring a smooth pen trace onto the chart paper.

The pen attached to the pen arm records the pressure on a calibrated chart.

A capsule stack is fitted for low-pressure ranges (i.e. below 2.5 bar) and the expansion of the system resulting from an increase in pressure is transferred by mechanical linkage to the pen arm in a similar way.

DESCRIPTION OF OPERATION OF TEMPERATURE RECORDER

As temperature rises, the fluid/gas in the thermometer bulb expands and partially uncoils the bourdon tube fitted inside the instrument.

This movement is transferred by a mechanical linkage to the pen arm which records the temperature on a calibrated chart.

The instrument is suitably compensated against normal ambient temperature variations by a bimetallic compensator arm forming part of the mechanical linkage.

DESCRIPTION OF OPERATION OF DIFFERENTIAL PRESSURE RECORDER

Differential pressure (produced by an orifice plate, Dall tube, Venturi or Pitot tube etc..) is measured by a bellows operated Differential Pressure Unit (DPU) mounted at the rear of the recorder.

The axial movement of the bellows is transferred by a torque tube within the unit to produce a rotational output which is transferred by mechanical linkage to the recording pen.

The measured value of differential pressure is displayed in red trace on a circular chart which is rotated at a constant speed by a mechanical, battery or electrical chart drive motor,

2

RECEIPT OF RECORDER

The Clearscan recorder complete with a packet of charts, door keys and pen pack(s) is dispatched in a protective casing which should preferably be replaced after inspection, as protection until the instrument is ready for installation.

The spare pen pack(s) and door keys are inside the protective case.

To assist with inspection, a label attached on the inside face of the case door states instrument serial number, chart number, range of each pen and the rotation speed of the chart drive.

Additional parts for pipe mounting versions are packed in the protective casing during transit.

RECEIPT OF TEMPERATURE RECORDER

The capillary tubing between the bulb and recorder is coiled for despatch purpose. Immediately prior to installation, this tubing must be uncoiled carefully in order to avoid twisting or kinking.

INSTALLATION AND MOUNTING - wall or panel mounting

Ideally the site chosen should be free from dust, corrosive fumes, vibration and extremes of temperature.

The instrument is suitably designed for outdoor weather conditions and protected against ingress of dust and water.

The recorder is suitable for wall or panel mounting using the brackets provided.

Refer to figure 1 for overall dimensions of the recorder and general installation.

371

41

114

312

490

483

420

56

 

53

PRESSURE CONNECTION

WALL MOUNTING

302

1/2" NPT STANDARD

 

OR 1/4" NPT OPTIONAL

 

327

CASE BREATHER

PANEL CUTOUT SIZE: 305 x 425

PANEL MOUNTING

Fig. 1a Outline Dimensions for 12 inch chart recorder (wall or panel mounting)

3

all dimensions are in mm

Clearscan™ Recorder Series - Operating and Service Manual

INSTALLATION AND MOUNTING - 2” pipe or post mounting

Ideally the site chosen should be free from dust, corrosive fumes, vibration and extremes of temperature.

The instrument is suitably designed for outdoor weather conditions and protected against ingress of dust and water.

The recorder is suitable for mounting onto a 60mm outside diameter post or pipe having a 2" nominal bore using the 'U' bolts provided.

Refer to figure 1 for overall dimensions of the recorder and general installation.

The post or pipe may be vertical or horizontal to the recorder but the recorder must be installed vertically.

371

41114

60mm O/D PIPE OR POST

490

65

483

420

56

53

PRESSURE CONNECTION 1/2" NPT STANDARD

116

302

CASE BREATHER

Fig. 1b Outline Dimensions for 12 inch chart recorder (2” pipe / post mounting)

all dimensions are in mm

4

INSTALLATION AND MOUNTING - Differential Pressure Recorder complete with 2” pipe/post or wall mounting

371

315

41

114

103

60mm O/D PIPE OR POST

1/4"NPT FEMALE

 

PORTS

HIGH

LOW

-VE

+VE

PRESSURE

PRESSURE

65

 

490

420

1/4"NPT FEMALE

PORTS

54

DIFFERENTIAL PRESSURE CELL

CASE BREATHER

STATIC

56

53

PRESSURE CONNECTION

1/2" NPT STANDARD

216

 

 

302

Fig. 1c Outline Dimensions for 12 inch chart recorder (fitted with Differential Pressure Unit)

all dimensions are in mm

60mm O.D. PIPE

 

TO MOUNT RECORDER

60

165

60mm O.D. PIPE TO MOUNT RECORDER

50

135

4 x 12 DIA. FIXING HOLES ON 50 x 72 CENTRES

4 x 12 DIA. FIXING HOLES ON 135 x 72 CENTRES

Fig. 1d Wall Mounting Dimensions using optional wall bracket kit

all dimensions are in mm

5

Clearscan™ Recorder Series - Operating and Service Manual

PROCESS CONNECTIONS - Pressure

To avoid confusion on instruments fitted with more than one measuring system, the connections are marked with the same colour as the corresponding recording pen colour.

The recorder is fitted with NPT threaded connection(s) and all pipelines attached to it must be secure and leak proof. PTFE sealing tape must be used to make a pressure tight join to the recorder connections.

Use pressure tubing of sufficient size and rating to make a connection from the measuring point in the flow pipe or vessel to the fitting(s) on the recorder.

Slope the run of the pipe-work in such a way that any condensate is drained away from the recorder, and fit an appropriate shut-off valve. For measurement of steam pressure and other hot vapours, form a condensate trap below the recorder.

It is recommended that a needle valve be installed in the pressure line close to the instrument to enable pressure to be admitted gradually. It can also dampen any pressure pulsation and/or fluctuation.

PROCESS CONNECTIONS - Temperature

Capillary tubing: The tubing between the bulb and recorder should be routed so that it is not subjected to large temperature changes and should be supported in cleats. Bends must not be less than 25mm (1inch) radius and under no circumstances must the tubing be cut.

Where the tubing is likely to be exposed to an extreme atmosphere, the exterior should be treated with corrosion resistant paint.

Location of Bulb (Detecting Element):

Immersion type bulb

The instrument bulb should be located where it is subject to the true temperature of the measured medium. Temperature gradient within the medium must be allowed for, and with bulbs allowing variable depth of immersion (compression gland type), the bulb position should be varied experimentally until the optimum position is found.

The full length of the sensitive portion must at all time be immersed in the medium, but direct contact with the source of heat to the medium must be avoided.

When securing the bulb in its location, it should be prevented from twisting.

Where a pocket is supplied, this should be securely installed before the bulb is inserted. It may be that the thermal response of a pocketed bulb is improved by filling the intervening space with a medium such as oil.

General Maintenance

keep the instrument clean and treat with care

where there is a risk of corrosion the bulb should be inspected periodically

if corrosion is evident, it should be removed by non-abrasive treatment

any contamination on the bulb should be removed

6

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