PRODUCT MANUAL
HT10X
HEAT TRANSFER SERVICE UNIT
HT10X
ISSUE 6
OCTOBER 2008
NOTE: Compatibility of HT10X with HT14 & HT16
In February 2006 a component becoming obsolete forced Armfield Ltd to
change the mains outlet connector (OUTPUT 1) at the rear of the HT10X
console and the corresponding plug on the mains lead of the HT14 and HT16.
No other accessories to the HT10X are affected by this change.
An adaptor ‘ADAPTOR1–HT10’ is available from Armfield Ltd that allows a
current HT10X to be used with an original HT14 or HT16. If the mains plug
on your HT14 or HT16 has exposed pins that do not mate with OUTLET 1 on
HT10X then ‘ADAPTOR1–HT10’ is required.
Similarly ‘ADAPTOR2-HT10’ is available from Armfield Ltd that allows an
original HT10X to be used with a current HT14 or HT16. If the mains plug on
your HT14 or HT16 has pins protected by a shrouded cover that does not
mate with OUTLET 1 on HT10X then ‘ADAPTOR2-HT10’ is required.
If you need an adaptor please contact Armfield Ltd at the address below
specifying if ‘ADAPTOR1-HT10’ or ‘ADAPTOR2-HT10’ is required for
correct functioning of the equipment:
Armfield Ltd
Bridge House
West Street
Ringwood
Hampshire
England
BH24 1DY
Telephone number:
+44 (0)142578781
Fax number:
+44 (0)1425470916
Email address:
support@armfield.co.uk
ARMFIELD LTD
PRODUCT MANUAL
HT10X
PAGE NO.
SAFETY
1
INTRODUCTION
5
RECEIPT OF EQUIPMENT
7
DESCRIPTION
9
INSTALLATION REQUIREMENTS
14
ASSEMBLY
15
CONNECTION TO SERVICES
16
COMMISSIONING
17
GENERAL OPERATING NOTES
18
ROUTINE MAINTENANCE
22
GENERAL SAFETY RULES
a
SAFETY IN THE USE OF EQUIPMENT SUPPLIED BY ARMFIELD
Before proceeding to install, commission or operate the equipment described in this
product manual we wish to alert you to potential hazards so that they may be avoided.
Although designed for safe operation, any laboratory equipment may involve processes or
procedures which are potentially hazardous. The major potential hazards associated with
this particular equipment are listed below.
l
INJURY THROUGH MISUSE
l
INJURY FROM ELECTRIC SHOCK
l
INJURY FROM INCORRECT HANDLING
l
BURNS FROM COMPONENTS AT HIGH TEMPERATURES
l
DAMAGE TO CLOTHING
Accidents can be avoided provided that equipment is regularly maintained and staff and
students are made aware of potential hazards. A list of general safety rules is included in
this manual, to assist staff and students in this regard. The list is not intended to be fully
comprehensive but for guidance only.
Please refer to the notes overleaf regarding the Control of Substances Hazardous to Health
Regulations.
1
The COSHH Regulations
The Control of Substances Hazardous to Health Regulations (1988)
The COSHH regulations impose a duty on employers to protect employees and others
from substances used at work which may be hazardous to health. The regulations require
you to make an assessment of all operations which are liable to expose any person to
hazardous solids, liquids, dusts, vapours, gases or micro-organisms. You are also required
to introduce suitable procedures for handling these substances and keep appropriate
records.
Since the equipment supplied by Armfield Limited may involve the use of substances
which can be hazardous (for example, cleaning fluids used for maintenance or chemicals
used for particular demonstrations) it is essential that the laboratory supervisor or some
other person in authority is responsible for implementing the COSHH regulations.
Part of the above regulations are to ensure that the relevant Health and Safety Data Sheets
are available for all hazardous substances used in the laboratory. Any person using a
hazardous substance must be informed of the following:
Physical data about the substance
Any hazard from fire or explosion
Any hazard to health
Appropriate First Aid treatment
Any hazard from reaction with other substances
How to clean/dispose of spillage
Appropriate protective measures
Appropriate storage and handling
Although these regulations may not be applicable in your country, it is strongly
recommended that a similar approach is adopted for the protection of the students
operating the equipment. Local regulations must also be considered.
2
USE OF EARTH LEAKAGE CIRCUIT BREAKER AS AN ELECTRICAL SAFETY DEVICE
The equipment described in this Product manual operates from a mains voltage electrical
supply. The equipment is designed and manufactured in accordance with appropriate
regulations relating to the use of electricity. Similarly, it is assumed that regulations
applying to the operation of electrical equipment are observed by the end user.
However, to give increased operator protection, Armfield Ltd have incorporated a
Residual Current Device or RCD (alternatively called an Earth Leakage Circuit Breaker ELCB) as an integral part of this equipment. If through misuse or accident the equipment
becomes electrically dangerous, an RCD will switch off the electrical supply and reduce
the severity of any electric shock received by an operator to a level which, under normal
circumstances, will not cause injury to that person.
At least once each month, check that the RCD is operating correctly by pressing the TEST
button. The circuit breaker MUST trip when the button is pressed. Failure to trip means
that the operator is not protected and the equipment must be checked and repaired by a
competent electrician before it is used.
3
HT15
HT11
armfield
HT12
HT10X HEAT TRANSFER SERVICE UNIT
MAINS
VOLTAGE CONTROL
/O
PORT
V/A/W/m /Lux/M/sec/L/min
2
R
L
Ua
MANUAL
V
Fw
REMOTE
TEMPERATURE ░C
INSTRUMENTATION
T12
T1
T11
T2
T3
T10
T9
ZERO
R
0V
T1
L
Ua
T4
T8
Fw
T5
T7
T6
TEMPERATURE OUTPUT 10mV/░C (6V MAX)
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
T12
0V
HT10X
HT16
HT14
HT17
HT13
4
INTRODUCTION
The Armfield range of heat transfer laboratory teaching equipment comprises seven small
scale accessories which demonstrate the three basic modes of heat transfer (conduction,
convection and radiation) which result from differences in temperature. The factors which
affect the rate of heat transfer can be investigated and some of the practical problems
associated with the transfer of heat can be clearly demonstrated.
The seven heat transfer accessories may be individually connected to a common bench top
service unit (HT10X) which provides the necessary electrical supplies and measurement
facilities for investigation and comparison of the different heat transfer characteristics.
The ability to change the type of demonstration quickly, without the use of tools, and the
fast response of the system (where practicable) to changes in heat input, temperature etc.
allows the relevant teaching exercises to be carried out in a relatively short period of time.
A singular advantage of the modular approach to the HT10X series is that the service unit
will allow students to carry out project work in heat transfer either by constructing their
own thermal models or by making additions to one of the original accessories.
The following heat transfer accessories are available:
HT11
HT12
HT13
HT14
HT15
HT16
HT17
Linear heat conduction
Radial heat conduction
Laws of radiant heat transfer and radiant heat exchange
Combined convection and radiation
Extended surface heat transfer
Radiation errors in temperature measurement
Unsteady state heat transfer
This product manual describes the function of the HT10X 'Heat Transfer Service Unit'.
Each of the individual heat transfer accessories (HT11 to HT17) is supplied with a
combined product and teaching manual. The product manual describes the operation of
the particular accessory when used in conjunction with the HT10X service unit in relation
to those functions normally associated with the laboratory technician. The teaching
manual describes the individual accessory in relation to those functions normally
associated with the student or operator, namely how to perform the Laboratory Teaching
Exercises appropriate to the accessory. Each exercise includes detailed instructions on how
to record the appropriate readings and which calculations to perform to analyse the
performance.
Appropriate Operational Procedures are included in the teaching manual to provide the
operator with pertinent information about how to operate the equipment.
The HT10X 'Heat Transfer Service Unit' is essential equipment which provides a regulated,
variable DC supply to the heating element on the appropriate heat transfer accessory.
Instrumentation on the service unit comprises a digital indicator with selector switch to
display the temperatures at relevant positions on the heat transfer accessory and a second
5
digital indicator with selector switch to indicate other relevant variables. All
measurements are available as voltage signals for direct connection to a PC via an optional
interface device (a PC interface and WindowsTM based software is supplied for each of the
heat transfer accessories with the Optional Educational Software/Data Logging
Accessory.)
The service unit is housed in a robust steel enclosure and designed for bench mounting.
Note that accessories HT11C, HT12C, HT14C and HT16C are designed to be used in
conjunction with the HT10XC Heat Transfer Service Unit and cannot be used with HT10X
because of additional functions included only on the HT10XC.
6
RECEIPT OF EQUIPMENT
1.
SALES IN THE UNITED KINGDOM
The apparatus should be carefully unpacked and the components checked against
the Advice Note. A copy of the Advice Note is supplied with this product manual
for reference.
Any omissions or breakages should be notified to Armfield Ltd within three days of
receipt.
2.
SALES OVERSEAS
The apparatus should be carefully unpacked and the components checked against
the Advice Note. A copy of the Advice Note is supplied with this product manual
for reference.
Any omissions or breakages should be notified immediately to the Insurance Agent
stated on the Insurance Certificate if the goods were insured by Armfield Ltd.
Your own insurers should be notified immediately if insurance was arranged by
yourselves.
7
A
B
C
D
armfield
E
HT10X HEAT TRANSFER SERVICE UNIT
MAINS
VOLTAGE CONTROL
/O
PORT
V/A/W/m /Lux/M/sec/L/min
2
R
F
L
Ua
MANUAL
V
P
Fw
REMOTE
TEMPERATURE ░C
INSTRUMENTATION
T12
T1
T11
T2
T10
T3
T9
ZERO
R
L
Ua
O
T4
T8
Fw
T5
T7
T6
TEMPERATURE OUTPUT 10mV/░C (6V MAX)
0V
T1
T2
T3
T5
T4
T6
T7
T8
T9
T10
T11
0V
T12
G
N
H
M
H
L
K
J
Front View of HT10X
Q
R
OUTPUT 1
A.C. ~ 4A MAX
O/P 3
X
OUTPUT 2
A.C. ~ 1A MAX
R.C.C.B
O/P 1
O/P 2
MAINS INPUT
A.C.~
OUTPUT 3
24V D.C. 10A MAX
W
V
U
T
S
Rear View of HT10X
8
DESCRIPTION
Refer to the diagrams on page 8.
The HT10X 'Heat Transfer Service Unit' is essential equipment designed to support the
operation of the seven Armfield small scale heat transfer accessories:HT11
HT12
HT13
HT14
HT15
HT16
HT17
Linear heat conduction
Radial heat conduction
Laws of radiant heat transfer and radiant heat exchange
Combined convection and radiation
Extended surface heat transfer
Radiation errors in temperature measurement
Unsteady state heat transfer
which may be purchased singly.
The appropriate heat transfer accessory is located on the bench top alongside the service
unit and connected to the service unit, as appropriate, using the leads incorporated on the
accessory.
The service unit provides a stabilised, variable low voltage DC supply to the heat transfer
accessory under evaluation. It incorporates the necessary instrumentation to measure the
variables associated with heat transfer, namely:
- temperatures
- heater power (voltage & current)
- heat radiated
- light radiated
- air velocity
- cooling water flowrate
The service unit requires a single phase electrical supply. A cold water supply is also
required for several of the accessories (cold water supply and drain connected directly to
the appropriate accessory).
The service unit is designed for safe operation as follows:
REAR OF SERVICE UNIT
The following facilities are provided on the rear panel of the service unit:The Residual Current Circuit Breaker (V) is a device for the protection of personnel in the
event of an electrical fault or short to earth. All electrical circuits inside the service unit
and all accessories connected to it are protected by this device. The operation, purpose and
testing of the Residual Current Device are explained in more detail on page 3. Normal
operation of the equipment is achieved with the switch in the UP position.
9
The service unit is provided with a 4 metre length of mains cable which is fitted with a
plug to suit the mains power input socket (W). The cable allows connection of the unit to
an appropriate electrical supply (refer to the section Connection to Services).
The mains power output socket OUTPUT 1 (Q) is a mains power source used for driving
external ancillary equipment up to 4 Amps maximum but specifically the accessories HT14
and HT16 which incorporate a mains powered centrifugal fan.
A circuit breaker (U) limits the current available from this socket and protects the service
unit and wiring in the event of a short circuit. The mains supply from OUTPUT 1 is at the
same voltage and frequency as the electrical supply to the service unit.
The mains power output socket OUTPUT 2 (X) is a mains power source used for driving
external ancillary equipment up to 1 Amp maximum but specifically to power the
Armfield IFD5 Interface Device, supplied with the Optional Educational Software/Data
Logging Accessory.
A circuit breaker (T) limits the current available from this socket and protects the service
unit and wiring in the event of a short circuit. The mains supply from OUTPUT 2 is at the
same voltage and frequency as the electrical supply to the service unit.
The low voltage DC export socket OUTPUT 3 (S) is used to provide variable DC voltage
from 0 to 24 V to the heater on the appropriate heat transfer accessory and provides
immunity from fluctuations in the mains electrical supply.
This supply is also used to operate the circulating pump when using the HT17 accessory.
The electrical lead and matching plug are integral with the appropriate accessory.
A thermal circuit breaker marked O/P 3 (R) limits the current available from this socket
and protects the service unit and wiring in the event of a short circuit.
Normal operation of the equipment is achieved with the switch on each of the above
breakers in the UP position (button depressed in the case of O/P 3). If any of the above
breakers are activated, this indicates a fault in the particular circuit and if the breaker will
not reset, further investigation will be required by a competent electrician.
FRONT OF SERVICE UNIT
The following facilities are provided on the front panel of the service unit:A mains switch (A), located on the front of the service unit allows the service unit to be
turned on and off as required and isolates all of the individual electrical circuits inside the
enclosure when switched off.
The variable DC voltage supplied to the heat transfer accessory, via socket OUTPUT 3 at
the rear of the service unit, is adjusted using the multi-turn potentiometer (C) marked
VOLTAGE CONTROL. The range of the output voltage is continuously adjustable from 0
Volts to 24 Volts DC using the multi-turn potentiometer. The selector switch (B), adjacent
10
to the potentiometer, should be set to the MANUAL position to allow adjustment using
the potentiometer. The selector switch is only set to the REMOTE position if the voltage is
to be controlled from an external signal via the 50 way I/O Port connector (F).
The actual voltage supplied can be monitored using the top panel meter (D) when the
measurement selector switch (E) is set to position V. The readout is calibrated directly in
Volts with a range of 0 to 24 VDC and a resolution of 0.1 Volts.
Similarly the current can be monitored when the selector switch (E) is set to position I. The
readout is calibrated directly in Amps with a range of 0 - 9 A and a resolution of 0.01 A.
Other relevant parameters on the heat transfer accessories can be measured as follows:
Thermal radiation R
A radiometer is incorporated on the HT13 to measure the thermal radiation. This
instrument is connected to the socket marked R (O) on the front of the service unit. The
thermal radiation is read on the top panel meter (D) when the measurement selector
switch (E) is set to position R.
The thermal radiation is indicated directly in units of Watts/metre2 over the range 0 - 333
W/m2 with a resolution of 1 W/m2.
A zero potentiometer (P) to the left of the radiometer socket allows any offset in the
reading from the radiometer to be corrected.
Light illumination L
A light sensor is incorporated on the HT13 to measure the light illumination. This
instrument is connected to the socket marked L (N) on the front of the service unit. The
light illumination is read on the top panel meter (D) when the measurement selector
switch (E) is set to position L.
The light illumination is indicated directly in units of Lux over the range 0 - 234 Lux with a
resolution of 1 Lux.
11
Air Velocity Ua
A vane type anemometer is incorporated on the HT14 and HT16 to measure the velocity of
the air passing through the duct. This instrument is connected to the socket marked Ua
(M) on the front of the service unit. The air velocity is read on the top panel meter (D)
when the measurement selector switch (E) is set to position Ua.
The air velocity is indicated directly in units of metres/second over the range 0 - 10 m/s
with a resolution of 0.1 m/s.
Cooling Water Flowrate Fw:
When the optional flow sensor is used in conjunction with the heat transfer accessories
HT11 or HT12 the sensor is connected to the socket marked Fw (L) on the front of the
service unit. The flow of cooling water is read on the top panel meter (D) when the selector
switch (E) is set to position Fw.
The flowrate is indicated directly in units of litres/min over the range 0 - 1.50 l/min with a
resolution of 0.01 l/min.
Where cooling water is required for the heat transfer accessory under evaluation, the
water and drain connections are made directly to the appropriate accessory.
Temperatures T1 - T12:
Temperatures on the various heat transfer accessories are measured using up to 12 type K
thermocouples installed in appropriate tappings on the accessory (thermocouples are
supplied with the accessory). Each thermocouple lead is numbered to allow connection to
the appropriate thermocouple socket (K) at the bottom of the front panel on the service
unit.
The required temperature reading is selected via a switch (G) and displayed on the
adjacent panel meter (J). Temperature readings are displayed directly on the meter in units
of °C.
Thermocouples T1 - T9 are connected using miniature plugs/sockets. Readings are in the
range 0 to 200°C with a resolution of 0.1°C.
Thermocouples T10 - T12 are connected using standard plugs/sockets. Readings are in the
range 0 to 600°C with a resolution of 1°C. (The sockets are polarised by size to prevent
high temperature thermocouples from being connected to low temperature channels.)
A row of banana sockets (I) on the front of the service unit allow any of the temperature
signals to be connected to a suitable chart recorder. The output voltage from these sockets
is 10 mV/°C (1 Volt corresponds to 100°C). The chart recorder input is connected to one of
the black 0 Volt common sockets (H) and the appropriate red socket (T1 - T12) as required.
12
A 50 way IDC socket (F) on the right hand side of the front panel (The Data I/O Port)
allows all of the temperatures and other measurements to be connected simultaneously to
a PC via an optional Armfield IFD5 interface device which is supplied with the Optional
Educational Software/Data Logging Accessory.
Educational and Data Logging Software is available for all of the HT10X range of Heat
Transfer equipment. Used in conjunction with the Armfield IFD5 interface device, which
connects the HT10X Service Unit to the parallel printer port of a PC, this provides a
comprehensive educational software environment within which the heat transfer
investigations can be performed. Refer to Armfield for further information on the
computer software available.
13
INSTALLATION REQUIREMENTS
ELECTROMAGNETIC COMPATIBILITY
This apparatus is classified as Education and Training Equipment under the
Electromagnetic Compatibility (Amendment) Regulations 1994. Use of the apparatus
outside the classroom, laboratory or similar such place invalidates conformity with the
protection requirements of the Electromagnetic Compatibility Directive (89/336/EEC) and
could lead to prosecution.
FACILITIES REQUIRED
Installation may be completed using a basic tool kit.
The 'Heat Transfer Service Unit' is designed for installation on a firm, level work surface,
such as a laboratory bench. Space should be allowed alongside the service unit for the
installation of appropriate heat transfer accessories.
As some of the heat transfer accessories require a permanent cold water supply during
operation the location should be adjacent to a sink unit or cold water supply with
appropriate drain. Where cooling water is required for the heat transfer accessory under
evaluation, the water and drain connections are made directly to the appropriate
accessory.
Several of the teaching exercises, when using the HT13 accessory, involve the
measurement of visible light. A darkened room will be required to allow accurate
measurements to be taken.
MAINS ELECTRICAL SUPPLY
The 'Heat Transfer Service Unit' requires connection to a single phase fused electrical
supply. Four metres of cable is supplied with the equipment, terminated with a plug to
suit the mains input connector (W) on the rear panel. Two versions of the service unit are
available:
HT10X-A
HT10X-B
220/240V/1ph/50Hz @ 10 Amps
120V/1ph/60Hz @ 20 Amps
No other services are required.
Overall dimensions of the HT10X are:
Width
Depth
Height
320 mm
390 mm
240 mm
The service unit requires one of the available heat transfer accessories (HT11, HT12, HT13
HT14, HT15, HT16 or HT17) to be connected to it to be fully operational.
14
ASSEMBLY
The 'Heat Transfer Service Unit' is delivered fully assembled and ready for use with one of
the heat transfer accessories HT11 - HT17.
15
CONNECTION TO SERVICES
Refer to the diagrams on page 8.
ELECTRICAL SUPPLY FOR VERSION HT10X-A
Before connecting the electrical supply ensure that the RCD/RCCB (V) and two miniature
circuit breakers O/P 1 (U) and O/P 2 (T) are in the OFF (down) position.
The equipment requires connection to a single phase, fused electrical supply. The standard
electrical supply for this equipment is 220/240V, 50Hz. Check that the voltage and
frequency of the electrical supply agree with the label attached to the supply cable on the
equipment. Connection should be made as follows:GREEN/YELLOW
BROWN
BLUE
Fuse rating
-
EARTH
LIVE (HOT)
NEUTRAL
6 AMP
ELECTRICAL SUPPLY FOR VERSION HT10X-B
Before connecting the electrical supply ensure that the RCD/RCCB (V) and two miniature
circuit breakers O/P 1 (U) and O/P 2 (T) are in the OFF (down) position.
The equipment requires connection to a single phase, fused electrical supply. The standard
electrical supply for this equipment is 120V, 60Hz. Check that the voltage and frequency of
the electrical supply agree with the label attached to the supply cable on the equipment.
Connection should be made as follows:GREEN/YELLOW
BROWN
BLUE
Fuse rating
-
EARTH
LIVE (HOT)
NEUTRAL
10 AMP
16
COMMISSIONING
Refer to the diagrams on page 8.
The following procedure is used for checking that the service unit is operating correctly.
A full commissioning procedure is given in the individual product manuals for each of the
heat transfer accessories. The following procedure relates to the HT10X 'Heat Transfer
Service Unit' only:Ensure that the service unit has been set up in accordance with the previous sections of
this manual.
1.
Ensure that the mains on/off switch (A) on the front panel is in the OFF position.
2.
Ensure that the mains electrical supply is connected and switched on.
Check the operation of the RCD/RCCB (V) by pressing the TEST button. The RCD
must trip when the button is pressed. If the RCD does not trip or it trips before
pressing the test button then it must be checked by a competent electrician before
the equipment is used.
3.
Ensure that the RCD/RCCB (V) and the two miniature circuit breakers O/P 1 (U)
and O/P 2 (T) on the rear panel are in the ON (up) position. Ensure that the thermal
circuit breaker O/P 3 (R) on the rear panel is latched (pressed in).
4.
Set the mains on/off switch (A) on the front panel to the ON position. Observe that
the two digital panel meters are both illuminated. As sensors are not fitted at this
stage the temperature display will indicate ambient temperature.
5.
Set the voltage control switch to MANUAL. Set the measurement selector switch
(E) to position V. Adjust the multi-turn potentiometer to zero (release the clamp
and turn the adjusting knob fully anticlockwise) then check that the reading
indicated on the panel meter D) is approximately 0 Volts. Gradually turn the
potentiometer clockwise and check that the reading Voltage indicated on the panel
meter increases. When the potentiometer is fully clockwise the reading should be 24
Volts.
6.
Switch off the service unit using the mains switch (A) on the front panel.
Further checks on the function of the service unit cannot be carried out unless an
appropriate heat transfer accessory is connected. The basic operation of the service unit
has been confirmed. Refer to the section GENERAL OPERATING NOTES in this manual
or the teaching manual supplied with each optional heat transfer accessory for further
information.
17
GENERAL OPERATING NOTES
SETTING THE HEATER VOLTAGE
(All accessories except HT17)
When operating the equipment manually using the front panel controls ensure that the
selector switch (B) is set to the MANUAL position. This allows the voltage supplied to the
heater to be adjusted using the multi-turn potentiometer (C) marked VOLTAGE
CONTROL.
The selector switch is only set to the REMOTE position if the voltage is to be controlled
from an external signal via the 50 way I/O Port connector (F).
The range of the output voltage is continuously adjustable from 0 Volts to 24 Volts DC
using the multi-turn potentiometer. (Ensure that the clamp on the side of the knob is
released before turning the knob.)
Note: The 24 volt DC supply is used to operate the circulating pump on the accessory
HT17. The pump is connected to the DC outlet socket (OUTPUT 3) on the rear
panel of the service unit. The speed of the pump can be adjusted by varying the
setting of the multi-turn potentiometer in the same way as changing the voltage to a
heater.
MEASURING THE POWER TO THE HEATER
(All accessories except HT17)
While adjusting the heater voltage the actual voltage supplied to the heater can be
monitored by setting the selector switch (E) to position V. The reading is displayed
directly in Volts on the top panel meter (D).
The current drawn by the heater in the accessory can be monitored by setting the top
measurement selector switch (E) to position I. The reading is displayed directly in Amps
on the top panel meter (D).
As the electrical supply to the heater is Direct Current the power supplied to the heater is
simply obtained from the product of the Voltage and Current, ie.
Heater Power Q = Voltage V x Current I
eg.
If V = 15.0 Volts and I = 2.00 Amps then Q = 2 x 15 = 30.0 Watts
Note: Some of the accessories incorporate a thermostat to limit the maximum operating
temperature. If the heater voltage is set too high, resulting in excessive temperature,
the current to the heater will be disconnected until the thermostat resets when the
temperature falls. If the display shows no current when voltage is applied to the
heating element check that the relevant temperature on the accessory is not
excessive. If the temperature is excessive set the Voltage Control to zero and allow
the thermostat to reset (Refer to the Operational Procedures in the teaching manual
supplied with the accessory for further information).
18
If the temperature of the accessory is not excessive but the display shows no current
when voltage is applied to the heating element check the following:
Check that the thermal breaker O/P3 (R) at the rear of the service unit is latched
(pressed in).
Check that the heater lead on the accessory is connected to the socket marked O/P3
(S) at the rear of the service unit.
MEASURING TEMPERATURES
(T1 - T12 as appropriate on all accessories)
To monitor any of the thermocouples installed on one of the heat transfer accessories
simply set the temperature selector switch (G) to the required position and read the
corresponding value on the lower panel meter (J).
Temperatures T1 to T9 are indicated in the range 4.0 - 200.0°C with a resolution of one
decimal place.
Temperatures T10 to T12 are indicated in the range 4 - 600°C with a resolution of no
decimal places.
MEASURING THERMAL RADIATION
(Radiometer on HT13)
When the radiometer is connected to the socket (O) marked R then the thermal radiation
can be read on the top panel meter (D) with the selector switch (E) set to position R.
The thermal radiation is indicated directly in units of Watts/metre2 (maximum 333
W/m2).
A zero potentiometer (P) to the left of the radiometer socket allows any offset in the
reading from the radiometer to be corrected.
MEASURING LIGHT ILLUMINATION
(Lightmeter on HT13)
When the lightmeter is connected to the socket (N) marked L then the illumination can be
read on the top panel meter (D) with the selector switch (E) set to position L.
The light illumination is indicated directly in units of Lux (maximum 234 Lux).
19
MEASURING AIR VELOCITY
(Anemometer on HT14 and HT16)
When the anemometer is connected to the socket (M) marked Ua then the air velocity can
be read on the top panel meter (D) with the selector switch (E) set to position Ua.
The air velocity is indicated directly in units of metres/second (maximum 10.0 m/s).
MEASURING COOLING WATER FLOW RATE
(Optional flow sensor on HT11 and HT12)
If the optional flow sensor SFT2 is connected to the socket (L) marked Fw then the
flowrate can be read on the top panel meter (D) with the selector switch (E) set to position
Fw. The cooling water flowrate is indicated directly in units of Litres/min (Maximum 1.50
l/min).
USING A CHART RECORDER
Each of the temperature measurements is available as a voltage signal suitable for
connection to a suitable chart recorder. The signals are accessible via a row of banana
sockets (I) on the front panel of the service unit.
Each thermocouple is conditioned to produce an output signal of 10 mV per °C.
For example the Voltage output is 0.5 VDC at 50°C.
The signal is obtained by connecting the chart recorder between the appropriate red
channel socket (I), eg. T1 and one of the black 0V common connections (H).
Note: Channels T1 to T9 are restricted to operation over the range 0 - 200°C (0 - 2 Volts
output). Channels T10 - T12 operate over the range 0 - 600°C (0 - 6 Volts output)
USING THE OPTIONAL EDUCATIONAL SOFTWARE/DATA LOGGING ACCESSORY
An I/O Data Port connector (F) on the right hand side of the front panel allows the voltage
signals from each of the measurements to be connected to the parallel port of a suitable PC
using an Armfield IFD5 interface device. This interface device together with the
appropriate WindowsTM based software is available as an optional accessory to
accompany the HT10X and heat transfer accessories HT11 to HT17. The operation of the
interface is described in the instruction manual supplied with the IFD5. The operation of
the WindowsTM based software is described in the help text included as part of the
software.
20
CONNECTIONS TO THE I/O DATA PORT
To allow access to the measurement signals in applications other than when using an
Armfield IFD5, the connections to the 50 way connector (F) are listed below for
information:PIN NO
CHANNEL NO
SIGNAL FUNCTION
Analog Outputs (0-5 V dc exported from socket):
1
Ch 0 signal
Temperatures T1 to T12 via analog switch
Temperatures T1 - T9 (0 - 200°C)
Temperatures T10 - T12 (0 - 600°C)
2
Ch 0 return
3
Ch 1 signal
Voltage V (0 - 24 Volts DC)
4
Ch 1 return
5
Ch 2 signal
Current to heater I (0 - 10 Amps)
6
Ch 2 return
7
Ch 3 signal
Thermal Radiation R (0 - 333 W/m2) HT13
8
Ch 3 return
9
Ch 4 signal
Light illumination L (0 - 234 Lux) HT13
10
Ch 4 return
11
Ch 5 signal
Velocity of air Ua (0 - 10 m/s) HT14 and HT16
12
Ch 5 return
13
Ch 6 signal
Flowrate of water Fw (0 - 1.5 l/min) HT11 and HT12
14
Ch 6 return
15-21
Not used
Analog Inputs (0-5 V dc input to socket):
22
DAC0 signal
Voltage output V (Remote operation of 0 - 24 Volts)
23
DAC0 ground
24-25
Not used
Digital Outputs ( 0/5 V dc):
26-37)
Not used
Digital Inputs (0/5 V dc):
38
Ch 0
39
Ch 1
40
Ch 2
41
42
43
44-46
47
48-50
Ch 3
Digital ground
Ch 4
Not used
Digital ground
Not used
Analog switch
Analog switch
Analog switch
Analog switch
Inhibit analog switch
21
ROUTINE MAINTENANCE
To preserve the life and efficient operation of the equipment it is important that the
equipment is properly maintained. Regular servicing/maintenance of the equipment is the
responsibility of the end user and must be performed by qualified personnel who
understand the operation of the equipment.
In addition to regular maintenance the following notes should be observed:1.
The 'Heat Transfer Service Unit' should be disconnected from the electrical supply
when not in use.
2.
The heat transfer accessory under evaluation should be disconnected from the
service unit and drained (if appropriate) after use.
3.
The thermocouple conditioning circuits (which provide readings from the
thermocouples fitted to each of the heat transfer accessories) are located on a PCB
inside the electrical console. These circuits are calibrated before despatch and
should not require recalibration. However, should recalibration become necessary
the appropriate zero and span potentiometers can be located using the diagram on
page 27.
This exercise should only be carried out by a competent electrician since live
electrical circuits inside the electrical console will be exposed when the lid is
removed.
A Type K thermocouple simulator should be connected to each socket in turn on
the front of the service unit and the corresponding zero and span potentiometers
adjusted to calibrate the circuit. Calibration at 0°C and 100°C is recommended on
channels 1 to 9, calibration at 0°C and 500°C is recommended on channels 10 to 12.
If a thermocouple simulator is not available then a type K thermocouple from one
of the optional heat exchangers can be used with crushed ice and boiling water as
the reference points.
4.
Test the RCD/RCCB by pressing the TEST button at least once a month. If the RCD
does not trip when the TEST button in pressed then the equipment must not be
used and should be checked by a competent electrician.
NOTE:
Maintenance of the HT10X 'Heat Transfer Service Unit' does not require
access to the electrical circuits or components located inside the metal
enclosure. However, in the event of an electrical problem or recalibration of
the thermocouple circuits being necessary, it may be necessary for a
competent electrician to gain access to the inside of the enclosure as follows:
Ensure that the service unit is disconnected from the electrical supply (not
just switched off).
Disconnect any accessory connected to the service unit.
22
Unscrew the four socket headed screws on the sides of the enclosure.
Carefully lift the top metal panel from the enclosure taking care to
disconnect the earth connection between the top and bottom sections of the
enclosure.
The electrical circuits inside the enclosure are accessible for working on.
A circuit diagram showing the mains and DC electrical circuits inside the
enclosure is included on page 25 to assist in fault finding.
Should it be necessary to remove the I/O PCB from inside the enclosure then
the I/O PCB Connections diagram on page 27 shows the location and
function of the electrical connectors on the PCB to aid reassembly
Reassembly of the service unit is the inverse of the above instructions.
Ensure that the earth connection between the top and bottom panels is
remade before replacing the top metal panel.
Details of the connections between the service unit and any of the accessories
is given in the appropriate product manual supplied with each accessory.
Note:
The 24 Volt DC power supply inside the enclosure (mounted on the base)
incorporates a 10 Amp fuse to protect the DC output from the supply. If no
output is available from the socket OUTPUTS (S) when thermal breaker
O/P3 is depressed then this fuse should be checked for continuity. The fuse
is located in an in-line holder adjacent to the smoothing capacitors on the
power supply.
The instrumentation switch mode DC power supply inside the enclosure
(mounted on the rear panel) incorporates a 2 Amp fuse to protect the mains
input to the power supply. If the panel meters on the front of the console do
not illuminate when the RCD and mains switch are on then this fuse should
be checked for continuity. The fuse is located in a holder at the bottom of the
PCB.
23
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24
25
This page left blank intentionally.
26
0V
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10 T11 T12 0V
TEMPERATURE OUTPUT 10mV/°C (6V MAX)
Fw
R
L
Ua
PSU
CONN 1
VOLTAGE CONTROL
CONN 11
CONN 6 CONN 8
CONN 2
CONN 7
CONN 5
+T11 - +T9 - + T7- + T5 - + T3 - + T1 -
CONN 16
T11 T9
T7
T2
T4
T6
VR3V
T8
VR1M
T11
VR1K VR2V
VR1D
VR1B VR2S
T1
T9
VR1F VR2T
T7
VR2R
VR1C
T3
T12
VR3T
VR3S
T5
T5
T10
T8
VR1H
T6
VR1A
VR1G VR2P
T3
VR1E
VR2N
ZERO
VR1J
T1
SPAN
VR3R
T4
VR3P
VR3N
T2
T10 T12
Location of Temperature
Calibration Potentiometers
on PCB
27
TEMPERATURE °C
V/A/W/m/Lux/M/sec/L/min
+ T2 - +T4- + T6 - +T8 - + T10 -+ T12 -
PCB Connectors
VR1L
V
R
CONN 9 CONN 12
CONN 13
I
T12 T1
T2
T11
T10
T3
T9
T4
T8
T5
T7 T6
L
Ua
Fw
PSR
CONTROL
PCB
CONN 10
GENERAL SAFETY RULES
1
Follow Relevant Instructions
a
Before attempting to install, commission or operate equipment, all
relevant suppliers’/manufacturers’ instructions and local regulations
should be understood and implemented.
It is irresponsible and dangerous to misuse equipment or ignore
instructions, regulations or warnings.
Do not exceed specified maximum operating conditions (eg.
temperature, pressure, speed etc).
b
c
2
Installation
a
Use lifting tackle where possible to install heavy equipment. Where
manual lifting is necessary beware of strained backs and crushed toes.
Get help from an assistant if necessary. Wear safety shoes where
appropriate.
Extreme care should be exercised to avoid damage to the equipment
during handling and unpacking. When using slings to lift equipment,
ensure that the slings are attached to structural framework and do not
foul adjacent pipework, glassware etc. When using fork lift trucks,
position the forks beneath structural framework ensuring that the
forks do not foul adjacent pipework, glassware etc. Damage may go
unseen during commissioning creating a potential hazard to
subsequent operators.
Where special foundations are required follow the instructions
provided and do not improvise. Locate heavy equipment at low level.
Equipment involving inflammable or corrosive liquids should be sited
in a containment area or bund with a capacity 50% greater than the
maximum equipment contents.
Ensure that all services are compatible with the equipment and that
independent isolators are always provided and labelled. Use reliable
connections in all instances, do not improvise.
Ensure that all equipment is reliably earthed and connected to an
electrical supply at the correct voltage. The electrical supply must
incorporate a Residual Current Device (RCD) (alternatively called an
Earth Leakage Circuit Breaker - ELCB) to protect the operator from
severe electric shock in the event of misuse or accident.
Potential hazards should always be the first consideration when
deciding on a suitable location for equipment. Leave sufficient space
between equipment and between walls and equipment.
b
c
d
e
f
g
a
3
Commissioning
a
Ensure that equipment is commissioned and checked by a competent
member of staff before permitting students to operate it.
4
Operation
a
Ensure that students are fully aware of the potential hazards when
operating equipment.
Students should be supervised by a competent member of staff at all
times when in the laboratory. No one should operate equipment alone.
Do not leave equipment running unattended.
Do not allow students to derive their own experimental procedures
unless they are competent to do so.
Serious injury can result from touching apparently stationary
equipment when using a stroboscope to `freeze´ rotary motion.
b
c
d
5
Maintenance
a
Badly maintained equipment is a potential hazard. Ensure that a
competent member of staff is responsible for organising maintenance
and repairs on a planned basis.
Do not permit faulty equipment to be operated. Ensure that repairs are
carried out competently and checked before students are permitted to
operate the equipment.
b
6
Using Electricity
a
At least once each month, check that ELCB's (RCCB's) are operating
correctly by pressing the TEST button. The circuit breaker must trip
when the button is pressed (failure to trip means that the operator is
not protected and a repair must be effected by a competent electrician
before the equipment or electrical supply is used).
Electricity is the commonest cause of accidents in the laboratory.
Ensure that all members of staff and students respect it.
Ensure that the electrical supply has been disconnected from the
equipment before attempting repairs or adjustments.
Water and electricity are not compatible and can cause serious injury if
they come into contact. Never operate portable electric appliances
adjacent to equipment involving water unless some form of constraint
or barrier is incorporated to prevent accidental contact.
Always disconnect equipment from the electrical supply when not in
use.
b
c
d
e
b
7
Avoiding fires or explosion
a
Ensure that the laboratory is provided with adequate fire extinguishers
appropriate to the potential hazards.
Where inflammable liquids are used, smoking must be forbidden.
Notices should be displayed to enforce this.
Beware since fine powders or dust can spontaneously ignite under
certain conditions. Empty vessels having contained inflammable
liquids can contain vapour and explode if ignited.
Bulk quantities of inflammable liquids should be stored outside the
laboratory in accordance with local regulations.
Storage tanks on equipment should not be overfilled. All spillages
should be immediately cleaned up, carefully disposing of any
contaminated cloths etc. Beware of slippery floors.
When liquids giving off inflammable vapours are handled in the
laboratory, the area should be ventilated by an ex-proof extraction
system. Vents on the equipment should be connected to the extraction
system.
Students should not be allowed to prepare mixtures for analysis or
other purpose without competent supervision.
b
c
d
e
f
g
8
Handling poisons, corrosive or toxic materials
a
Certain liquids essential to the operation of equipment, for example
mercury, are poisonous or can give off poisonous vapours. Wear
appropriate protective clothing when handling such substances. Clean
up any spillage immediately and ventilate areas thoroughly using
extraction equipment. Beware of slippery floors.
Do not allow food to be brought into or consumed in the laboratory.
Never use chemical beakers as drinking vessels.
Where poisonous vapours are involved, smoking must be forbidden.
Notices should be displayed to enforce this.
Poisons and very toxic materials must be kept in a locked cupboard or
store and checked regularly. Use of such substances should be
supervised.
When diluting concentrated acids and alkalis, the acid or alkali should
be added slowly to water while stirring. The reverse should never be
attempted.
b
c
d
e
9
Avoiding cuts and burns
a
Take care when handling sharp edged components. Do not exert
undue force on glass or fragile items.
Hot surfaces cannot, in most cases, be totally shielded and can produce
severe burns even when not `visibly hot´. Use common sense and think
which parts of the equipment are likely to be hot.
b
c
10
Eye protection
a
c
Goggles must be worn whenever there is a risk to the eyes. Risk may
arise from powders, liquid splashes, vapours or splinters. Beware of
debris from fast moving air streams. Alkaline solutions are particularly
dangerous to the eyes.
Never look directly at a strong source of light such as a laser or Xenon
arc lamp. Ensure that equipment using such a source is positioned so
that passers-by cannot accidentally view the source or reflected ray.
Facilities for eye irrigation should always be available.
11
Ear protection
a
Ear protectors must be worn when operating noisy equipment.
12
Clothing
a
Suitable clothing should be worn in the laboratory. Loose garments
can cause serious injury if caught in rotating machinery. Ties, rings on
fingers etc. should be removed in these situations.
Additional protective clothing should be available for all members of
staff and students as appropriate.
b
b
13
Guards and safety devices
a
Guards and safety devices are installed on equipment to protect the
operator. The equipment must not be operated with such devices
removed.
Safety valves, cut-outs or other safety devices will have been set to
protect the equipment. Interference with these devices may create a
potential hazard.
It is not possible to guard the operator against all contingencies. Use
common sense at all times when in the laboratory.
Before starting a rotating machine, make sure staff are aware how to
stop it in an emergency.
Ensure that speed control devices are always set at zero before starting
equipment.
b
c
d
e
14
First aid
a
If an accident does occur in the laboratory it is essential that first aid
equipment is available and that the supervisor knows how to use it.
A notice giving details of a proficient first-aider should be prominently
displayed.
A `short list´ of the antidotes for the chemicals used in a particular
laboratory should be prominently displayed.
b
c
d