Isotech 915 Specifications

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Stirred Liquid Baths

-65 to 300°C

915 Parallel Tube

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Three Models Covering -65°C to 300°C

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Excellent Uniformity

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Uncertainties to 0.0005°C

The 915 is, no question, the finest stirred liquid parallel tube
bath produced.

Using best practise ratio methods of comparison calibration
uncertainties of less than 1mK can be obtained. The bath
can also be used to realise ITS-90 Fixed Point Cells (Mercury to
Tin Points) with absolute uncertainties to less than 1mK.

The Isotech Parallel Tube Liquid Bath is a development of the
previous 815 model and has many features which enhance
its performance and enable ease of operation. It is suitable
for the calibration of Liquid in Glass Thermometers, Industrial
Platinum Resistance thermometers, Standard Platinum
Resistance Thermometers, Thermocouples and Industrial
Temperature sensors. It can also be used with fixed point cells.

The temperature range of the standard 915 liquid calibration
bath (915H) is 40°C to 300°C. When the 915 is used in
conjunction with our external chiller the low temperature limit
can be extended to -65°C.

The 915 has a wide temperature range using silicon oils and
other suitable liquids. All components in contact with the
liquid are of stainless steel and are insulated with materials
which are completely safe in use. The 915 used in conjunction
with a chiller, utilizes the latest ozone friendly gases.

Liquids are circulated by a propeller which mixes and forces
the liquid through a specially designed orifice in the rear of
the two parallel tubes. A variable speed motor optimizes the
flow as the viscosity of the liquid changes. Below the orifice
plate liquid is circulated over a mineral insulated heater and
temperature sensors which control the temperature of the bath.
The liquid flows up the calibration tube and weirs over the tube
into a collection tray where it returns to the rear tube for
recirculation. An angled side entry tube enables a refrigeration
cooling probe to be inserted in the rear of the two parallel tubes.

The standard temperature controller has resolution from 0.01°C
to 0.1°C which auto scales to suit the four digit display (all digits
can be read with the Cal NotePad Software).

The standard controller can be replaced with a model offering a
display resolution of 0.01°C over the whole range. This High
Stability controller (Option 915/E) also offers better short term
temperature stability, see table.

With the high cost of some silicon oils the 915’s seven litre
capacity makes it relatively inexpensive to fill compared to
many other baths.

The changing of liquid is easily enabled by using the fitted drain.
The design also allows for the expansion of liquids when being
raised to a particular calibration temperature.

Model 915LW 915MWE 915H

Temp Range -65°C – 40°C -30°C – 40°C 30°C – 300°C

Volume 100mm diameter, 400mm deep (7 litres)
or 100mm 530mm deep (Option 915D)

Absolute Stability:
High Stability Controller ±0.0006°C (Water, 50°C) ±0.002°C (Oil, 100°C)
Standard Controller ±0.004°C (Water, 50°C) ±0.007°C (Oil, 100°C)

Vertical Uniformity ±0.0002°C (Water, 50°C)

Communications Includes Serial Interface, PC Cable and Software

Dimensions 580mm wide, 640mm deep, 1020mm high

Weight 90kg 75kg 45kg

Safety Compliant to CE Regulations

Power 1kW (excluding Chiller) 108-130 or 208-240V, 50/60Hz

How to Order 915LW 915MWE 915H

Refer to Evaluation Report for Full Details

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For customers who require lower temperatures the range
of the 915 bath can be extended by the addition of a chiller
unit, see photograph below and the chart of model types
available.

Important

Chiller probes must be removed from the Calibration Bath
when used above their maximum temperature as stated
above.

The chiller unit’s probe (203mm long by 32mm diameter)
is inserted into the angled side entry tube, accessible from
the top of the cabinet, leaving the calibration volume of the
bath unchanged.

The following chiller options are available, we recommend
and supply the following:

Order Description Temperature
Code Range min/max

915/10 Single Stage Wide Range Chiller -30°C 40°C
915/11 Dual Stage Wide Range Chiller -65°C 40°C

These chillers have both good reliability and wide operating
ranges. They contain safe, ozone friendly gases.

The temperatures stated above assume an ambient within
the range of 20°C to 25°C.

Controller Note:

The standard and enhanced controllers include features
custom designed for Isotech by a world-leader in temperature
control technology. Power feedback is used to stabilise
against supply voltage changes, leading to greater
stability. A digital filter circuit ensures high integrity of
measurement correcting for drift, rejecting 50/60Hz
pick-up and filtering out other sources of input noise.

Health and Safety Notice

Rooms in which high temperature liquids are used should be
ventilated or have extraction facilities. Although the overall
temperature range of the bath is -65°C to 300°C the practical
temperature range which can be achieved is dictated by
the liquid being used and the ambient temperature.

Refer to ‘Liquid Selection Guide’ on page 73.

The High Stability Controller (Option 915/E) has a resolution of
better than 0.25µV which combined with powerful filtering
provides outstanding temperature stability.

915-05-38

915/05

(Block not

included)

915/03

915/11

915/02

915/01b

915/01a

Accessories

http://www.isotechna.com

915/01a Available for the Isotech Parallel Tube Bath is a variable depth aluminium equalising block containing

four drilled pockets 8mm diameter by 120mm deep in which temperature sensors can be placed and is
suitable for use with silicon oils.
The equalising block is suspended centrally within the calibration tube and is easily removed.

915/01b As an alternative to the above a copper equalising block, dimensionally the same as 915/01a, may be

supplied. This block is more suitable for use in water and other liquids.

915/D Increased depth Calibration Tube Assembly. Working volume is 100mm diameter by 530mm deep. This

variant allows for the calibration of very long thermometers, typically the calibration of long liquid in glass
thermometers. See also 915/02.

915/02 This assembly will hold up to 12 liquid in glass thermometers (maximum diameter 12.7mm) radially and

a centre mounted standard sensor. The assembly may be rotated allowing systematic calibration. The
assembly is designed for partial or full immersion of thermometers.

915/03 Monocular and Support. Useful for viewing and magnifying the liquid column within the thermometer

being calibrated. This ancillary piece of equipment is used in conjunction with 915/02 Liquid in Glass
Thermometer Support Kit.

915/05 Calibration Tube Cover. The cover consists of a square enclosure containing baffles and fits over the

calibration tube area insulating the circulating liquid from ambient air. Access for temperature probes
remains at the top of the enclosure. An equalising block may also be supported from this assembly.
Maximum operating temperature 180°C.

915/07 Medium Temperature Silicon Oil. Temperature Range 40°C to 180°C.

Flash Point 300°C.

915/08 High Temperature Silicon Oil. Temperature Range 150°C to 250°C.

Flash Point 315°C.

915/09 Very High Temperature Silicon Oil. Temperature Range 40°C to 288°C.

Flash Point 288°C.

915/E Controller provides 0.01°C resolution over the full temperature range with enhanced short term temperature

stability.

NOTE: Read all safety information concerning

liquids which you intend to use in the
bath and use only approved liquids.

Fixed Point Calibration ITS-90
Cell Basket Assemblies
(Excluding Cells)

915-05-43 Small Mercury Cell Kit
915-05-44 Large Mercury Cell Kit
915-05-41 Small Water Triple Point Cell Kit
915-05-40 Large Water Triple Point Cell Kit
915-05-39 Small Gallium Cell Kit
915-05-38 Large Gallium Cell Kit
915-05-42 Slim Cell Kit

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