Rototherm C105 User Manual

C105 Circular Case Recorder

Operating Instructions

Fig. 1.

CONTENTS

	Page No.		Page No.
INTRODUCTION	2	MAINTENANCE	11
Identification	2	Cutting a programme cam	11
Specification	3	Pen Adjustment	11
INSTALLATION	4	Calibration	11
		Servicing	12
Mounting	4	Wet and Dry Bulb Water Bath	13
Access to Recorder	5
Process Connections	5	SPECIAL INSTRUCTIONS & DIAGRAMS	14
Electrical Connections	5
OPERATION	6	FAULT FINDING	15
Mechanical Clock	6	SPARES LIST	15 & 16
Fitting a Chart	6
Set Pointer Adjustment	6
Inking System	6
Zero Adjustment	7
Start-up Check	7
Start-up Procedure	7
Description of Operation	8
Electrical alarm/control system	10
Programme Control	10

The chart drive and control system on this instrument may be operated from a mains voltage supply. The mains must be switched off before making any mechanical adjustments other than of the set pointers or carrying out any maintenance or fault finding procedures. When making electrical adjustments observe the warning notes in the text.

instrumentation and control

INTRODUCTION

The C105 series of instruments is designed to measure, record and control process variables such as temperature, pressure and humidity. A maximum of two measuring systems is provided in each instrument; a fluid expansion type or bimetallic system is used for temperature recording, a hygroscopic element or a wet and dry bulb system for humidity and a Bourdon tube or diaphragm for pressure measurement. The measured values are continuously recorded on a calibrated circular chart which is rotated at a constant speed by a mechanical or electric clock. Control of the process variable is provided electrically.

Each Pen

Basic

No. of

Alarm or Control Mode

Set Points

Programme

Type

Measuring

Measured

Control Cam

No. 1

No. 2 Nos. 3 & 4

(Single Pen

Number

Points

Variable

only)

C10

5 One

1 Temperature

17

Record only

–

–

–

–

–

Recorder

pen

(Fluid

with

expansion

Electric Alarm/Control

Position of Pen in relation to

105mm

6 Two

system)

with Relay Output

Set Point when Relay is energised

pen

00

Two Step

Above

–

None, or any

– or C

travel

pen

2 Pressure

on

(‘C’ Spring–

01

Two Step

Below

–

combination

– or C

circular

316 st.steel)

05

Three Step

Below

Below

applicable

–

chart

3 Pressure

06

Three Step

Above

Above

to Set Points

–

09

High-low

Above

Below

No. 1 & 2

–

(Spiral

03

Double 2 Step

Above/Above

–

– or C

Bourdon –

04

Double 2 Step

Below/Below

–

– or C

phosphor

bronze)

Contact Action at Set Point

4 Pressure

Electric Alarm/Control

when Pen moves towards

Contacts only – no Relay

outside of Chart

(Spiral

Bourdon –

60

Two Step

–Contact Mode C

Make

–

– or C

321 st.steel)

61

Two Step

–Contact Mode A

Break

–

None, or any

– or C

5 Pressure

65

Three Step

–Contact Mode AA

Break

Break

combination

–

66

Three Step

–Contact Mode CC

Make

Make

applicable

–

Capsule

69

High-Low

–Contact Mode CA

Make

Break

to Set Points

–

Stack –

63

Double 2 Step

–Contact Mode D

Make/Make

–

No. 1 & 2

– or C

beryllium

64

Double 2 Step

–Contact Mode B

Break/Break

–

– or C

copper)

6 Pressure

(Diaphragm

Stack –

beryllium

copper)

7 Relative Humidity

(Goldbeater skin)

– External

9 Pressure

(Coiled Tube –

316 st.steel

Notes:

Code No. is built up thus:

Single Pen	C105/1 1 63 C
	(

One Pen

Temperature

Double 2 Step –

Contacts only (no relay)

Programme Cam

Two Pen	C 1 0 6 / 3 0 0 / 1	1 7
	(	(

Two Pens

No. 1 Pen – Pressure (Bourdon)

– 2 Step Elec. Alarm

with Relay

No. 2 Pen – Temperature

– Record only

2

Specification

General:

Chart diameter

Writing width

Intrinsic error

Operating temperature limits

Operating humidity limits

Zero error due to ambient temp. variations Chart speeds

Chart drive

Power supply voltage and frequency Mounting

Temperature measuring instruments: Measuring systems

Maximum length capillary

Minimum span

Maximum span

Span limits

Pressure measuring instruments:

Measuring system

Minimum span

Maximum span

Span limits

Connection size

Humidity measuring instruments:

Measuring systems

Spans

Operating temperature limits

Operating humidity limits

Maximum length of capillary

(wet and dry bulb system) Electric alarm or control:

Instrument contacts

Contact action

Relays

Relay action

Overall dimensions

Panel cut-out

Maximum panel thickness

Weight

255mm

105mm

± 1% span maximum (±2% R.H. for hygroscopic membrane system)

–10o to +50oC	678	Except for
0 to 80% R.H.		humidity recorders

±0.05% span/oC typical

1 rev every 12 hours, 24 hours or 7 days

Synchronous electric motor or mechanical clock

200/250V or 100/120V, 50 or 60Hz

Wall or panel

Fluid expansion

30m

40oC

500oC

– 30oC to +600oC

Capsule stack, Bourdon tube or coiled tube

0 to 1 bar vacuum or pressure.

1200 bar

–1 bar to 1200 bar

Ranges up to 40 bar: a inch B.S.P.) with nut and tail Ranges over 40 bar: 2 inch B.S.P.) piece for 8mm tube

Sensitive hygroscopic membrane and fluid filled system for temperature measurement, or wet and dry bulb fluid expansion systems.

20 to 100% R.H. (hygroscopic membrane);

0 to 40oC (fluid filled systems)

0 to 40oC

30 to 85% R.H.

30m (each bulb)

20mA inductive or 30mA non-inductive load max.

Make above or below set point as required

Delayed action double pole change-over, 5A, 240V 50Hz non-inductive load, as standard

(Refer to wiring Diagram, p.14).

Energised above or below set point as required.

350mm wide; 137mm deep; 350mm high (Temp & R.H. 582mm high)

318mm diameter

25mm

10kg

3

INSTALLATION

Mounting

The instrument can be wall or panel mounted using the same fixing brackets. Do not install near any very hot apparatus, e.g. ovens, steam pipes or flues. Mount the recorder vertically in a position free from vibration and excessive temperature.

For panel mounting remove the fixing screws and rotate the fixing brackets so that the instrument can be inserted in the hole in the panel. Return the brackets to their original position and insert the fixing screws. Tighten the screws until they bear against the back of the panel.

Hygroscopic measuring instruments have external measuring elements requiring a clearance of 240mm below the case, and must be wall mounted.

Temperature Recorder	Pressure Recorder	Panel Mounting
		41 mm 83 mm

350 mm

	Cable gland for	a” or 2” B.S.P. union with nut,
	w” conduit
		and tailpiece

Temperature and Relative Humidity Recorder

Wall Mounting

Three holes at 120º on 340 mm p.c.d. to take 6.4 mm diam. screws

for wall mounting

Panel cut-out dia. 318 mm

Fig. 2.

4

Access to Recorder

To open the door, unlock, and turn the latch anticlockwise. As the door is opened the pen lifter raises the pen (or pens) away from the chart. Remove the chart (see page 6).

If the instrument is connected to the mains, switch off the mains supply before dismantling further.

For access to the terminal blocks remove the lower plastic plate from behind the chart by undoing the one retaining screw.

For access to the relays and measuring systems, first remove the chart. Unhook the pens from their mounting (see Fig. 3.). Remove the three screws from the outside edge of the chart plate. (The pen lifter is secured by one of these screws and must also be removed). Lower the chart plate carefully. The chart motor is mounted on the back of the chart plate and if the motor is an electric one it remains connected to the terminal block in the lower part of the case.

When replacing the chart plate reverse the above procedure. The coil on the pen lifter should be against the side of the case when the retaining screw is tightened.

Process Connections

To avoid confusion on instruments with more than one measuring system, setting pointers are labelled and Bourdon tube capillary connections to the instrument are painted with the same colours as the inks used for the corresponding pens.

Process connections – temperature measuring instruments:

Install the sensing element (bulb) of the instrument in the apparatus where the temperature is to be measured. The circulation around this element should be good and it should not be too close to any heating or cooling coil or other controlling medium. Fasten the capillary tubing at frequent intervals to rigid supports avoiding sharp bends of less than 50mm. radius anywhere along its length. The tubing must not touch or run close to any hot apparatus and should take the path least subject to temperature variation. If the temperature source is likely to move or vibrate allow one or two coils of 100mm. diameter of the capillary tube to eliminate stress of the tubing.

If the atmosphere around the capillary tube is likely to be corrosive, paint the tube with anti-corrosive paint and ensure this is maintained.

Process connections – pressure measuring instruments:

Connect the Bourdon tube sensing element to the measuring point on the apparatus using pressure tubing of the same or similar material as the Bourdon tube and of sufficient pressure rating. Slope the run of the tubing so that any condensate is drained away from the instrument and does not affect the accuracy of measurement. For measurement of steam pressure or other hot vapours, form a condensate trap below the instrument.

Process connections – humidity measuring instruments (wet and dry bulb):

Install the sensing elements (bulbs) where the humidity is to be measured as described for temperature measuring instruments. The wet bulb (red pen system) is kept moist by a fabric covering, forming a wick which dips into a constant level water bath. A distilled water supply tank should be connected to the inlet feed pipe with a head of between 1 and 6 metres.

It is important to install the bulbs in a position where the air speed is 3.6 metres per second or more. Below this speed inaccuracies of bulb depression may occur. The air should pass over the bulbs in such a direction that the water evaporating from the wet bulb does not pass over the dry bulb. The water must be kept clean and free from impurities. The temperature of the bath and all piping must not fall below 0oC. See also page 13.

Electrical Connections

Before making any connections to the instrument switch off the mains supply to be connected.

All electrical connections are made to terminal blocks in the lower part of the case behind the lower section of the chart plate.

Insert the leads through the cable gland in the underside of the case (see Fig. 2.) and make the connections as shown on the terminal labels or Wiring Diagram (page 14). The live line should be switched and fused with a 2 amp fuse. If the instrument is mounted on an insulated panel the case should be earthed.

5