Temperature Switches
Rototherm/HNL manufacture a wide range of temperature switches with both electrical outputs and pneumatic outputs. These include ATEX certified temperature switches suitable for use in hazardous areas.
Series 700 is a mechanical temperature switch - the Series 800 temperature switch is an electronic device that also functions as a temperature indicator and transmitter. Both are available with aluminium or stainless steel housings and either direct or capillary mounting.
Series 700
• Ranges from -50 to +400 Deg C
• Wide range of output switches
• Direct and remote mounting versions available
• Field Adjustable
• Excellent accuracy and reliability
Rototherm/HNL’s most popular temperature switch Mechanical Temperature Switching / Wide selection of Ranges and Outputs / Electrical & Pneumatic outputs.
For each of these both Electrical and Pneumatic outputs are available.
The electrical outputs are available for switches to be used in Hazardous (potentially explosive atmosphere) areas (Exd, ExnC & ExtD, Exia or I.S. compatible) or for Standard (non-hazardous) areas.
Due to the wide range of options available, a Series 700 switch can be supplied for most applications. In addition to the standard options detailed here HNL can design a switch to your own specification if required.
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Series 700 Standard Version
These temperature switches are designed
to provide electrical output switching for
non-hazardous area applications.
A large selection of output switches are
available providing the options
listed below:-
Fixed or Adjustable Differential
Single (S.P.D.T.) or Twin Switch (2 off
S.P.D.T. effectively D.P.D.T.)
Gold or Silver Contacts
Series 700 Pneumatic Version
Pneumatic Output Temperature Switches
provide the switching
of a compressed gas supply (generally air)
at a pre-determined
temperature.
The different pneumatic output
switching options are listed below:-
Code 61 - the pilot supply is used to
operate a 3 port changeover valve.
This switch has a fixed switching
differential.
Code 64 - as code 61 above but with
an adjustable switching differential.
Code 67 - primarily used when the
pilot supply is natural gas as it does
not have a continuous consumption of
pilot gas. This switch has only two
bulkhead connections - the pilot
supply and the output. The output
pressure is zero below the switch setpoint
and equal to the supply pressure above it.
Code 68 - as code 67 above but with the
reverse output - the output pressure is
equal to the supply pressure below the
switch setpoint and zero above it.
Code 71 - Primarily used for providing an
input into low pressure (1.4 bar / 20
p.s.i.) logic systems. This switch has only
two bulkhead connections - the pilot
supply and the output. The output switch
can be configured to provide an output on
either a rising or falling pressure.
Code 81 - as code 61 above but for lower
pressure operation.
Series 700 EExd Version
These temperature switches are designed
to provide electrical output switching for
Potentially Explosive Atmosphere
applications.
The Certifications available are listed
below:-
Exd Switches
(Cert. No: Baseefa07ATEX0055X)
Enclosures are certified Exd IIC T4/
T5/T6 to EN60079-0 & EN60079-1.
ExnC & ExtD Switches
(Cert. No: HNL07ATEX0001X)
Enclosures are certified EExnC IIC T4/
T5/T6 & ExtD A22 IP66 100°C to
EN 60079-0, EN 60079-15, EN 61241-
0 & 61241-1.
Exia Switches
(Cert. No: Baseefa06ATEX0231X)
Enclosures are certified Exia IIC T5/T6
to EN 60079-0 & EN 50020.
I.S. Compatible
Series 700 switches are classified as
simple apparatus, allowing use
in an I.S. circuit without individual
certification.
Series 800
The Series 800 Smartstat is a microprocessor controlled switch, transmitter and indicator, which enables several instruments to be replaced with a single device. Smartstats are available for the measurement of pressure / differential pressure (P & DP) and temperature (T).
Replacing a transmitter, switches and a gauge with a single Smartstat reduces equipment costs. Additionally there are reductions in documentation, installation time/ fittings/cabling, and calibration/maintenance costs.
Increased Accuracy/Repeatability
The Smartstat provides greater accuracy and repeatability than a conventional mechanical switch. Very large and very small switching differentials can be achieved without compromising accuracy.
Ease of Calibration
Pushbutton calibration of switch setpoints and 4-20mA calibration can be carried out on site without additional test equipment or tools.
Additional Features
Because the Smartstat is microprocessor based additional features are easily provided through the software including:
• Programmable switching delays - the switching on or off (or both) of the relays may be delayed from 0.5 seconds to 15 minutes. This is particularly useful for preventing unwanted switching due to pressure transients.
• Display of MAXimum and MINimum pressures recorded by the Smartstat.
• Display of transmitter output in mA.
• Reversal of transmitter output 20-4 mA instead of 4-20 mA.
• Square-root extraction to provide 4-20mA output proportional to flow using a DP Smartstat.
• Displayed units of measurement - can be changed by the user as required.
Series 800 Smartstat Temperature Switch
There are some temperature switching
applications that are very demanding due
to the need for:
• Very high (or low) temperatures.
• High accuracy and repeatability.
• Very large (or small) switching differentials.
• High frequency switching operation.
• Low frequency switching operation (once per year).
• Regular need to change switching temperatures.
These requirements may exceed the
capabilities of conventional mechanical
temperature switches, the Smartstat was
designed to overcome these problems.
• Smartstat RTD elements can be used to provide ranges from -200°C to 400°C.
• Typical repeatability is 0.1%.
• Two independent single-pole, double-throw (SPDT) relays are fitted in the Smartstat, the operating points of which can be set anywhere within the range. The switching differential can be set from 1 digit to 100.0% of range without loss of accuracy.
• Being almost entirely ‘solid state’ the Smartstat can provide up to 100,000,000 switching operations. It can respond to changesin temperature more rapidly than a mechanical temperature switch.
• With a mechanical switch testing the operation regularly is the only way to ensure that it is operating correctly. With the Smartstat the continuous temperature display serves to indicate that the device is operating correctly and will switch when required.
• Pushbutton calibration of switch setpoints can be carried out on site without additional test equipment or tools.
• In addition to its function as a high accuracy temperature switch the Series 800 Smartstat also functions as a temperature transmitter and temperature indicator enabling significant cost savings as several instruments can be replaced with a single device.