7
300544652_002_C1 - 11/2016 - © Leybold
Description
The TTR 91 N and TTR 96 N THERMOVAC series vacuum transmitters offer a wide measuring range from 5×10
-5
to 1000 mbar and are based on the measurement of thermal conductivity in a small cavity on a MEMS Pirani silicon
chip sensor.
The TTR 91 N and TTR 96 N THERMOVAC transmitters can be used in a variety of applications as standalone
units or with Graphix controllers (P/N: 230680V01, 230681V01, 230682V01) and the Display controllers (P/N:
230001, 230024, 230025). All THERMOVAC transmitters are backward compatible with Graphix, Display and
Center controllers.
Each transmitter is individually tested throughout the measuring range before leaving the factory. A test report is
included in the package. In addition, each transmitter pressure reading is individually temperature-compensated
within the specified operating temperature range.
The transmitters have up to three mechanical relays which can be used for process control, for example
interlocking valves or pumps. The analog voltage output can be interfaced to external analog equipment for
pressure readout or controlling.
Sensor technology
The transmitters have a single MEMS Pirani (MEMS = Micro-Electro-
Mechanical-System) sensor element whose measurements are based
on measurement of thermal conductivity. The MEMS Pirani sensor
consists of a silicon chip with a heated resistive element forming one
surface of a cavity. A cover on top of the chip forms the other surface of
the cavity. Due to the geometry of the sensor, convection cannot take
place within the cavity and consequently the sensor is insensitive to
mounting position. Gas molecules are passed by diffusion only to the
heated element where the heat loss of the gas is measured. The
sensor element is very robust and can withstand high G-forces and
instant air inrush.
Applications
The transmitters can be used in many different vacuum applications within e.g. the industrial application, research
and development, semiconductor, analytical and coating industries:
General vacuum pressure measurement
Fore line and roughing pressure measurement
Gas backfilling measurement and controlling
Mass spectrometer control
Activation of UHV gauge
System process control
Sense abnormal pressure and take appropriate security measure using relay set points
Control system pressure
P/N: 230045V02 and 230047V02 contain Parylene-HT® coated sensors.
Parylene-HT® is a conformal coating with excellent gas barrier properties with no outgassing. Sensors coated with
Parylene-HT® offer better resistance against various corrosive gases compared to the standard MEMS Pirani. The
coating covers the entire sensor chip, including wiring. Hence the only material exposed to the process gas is the
Parylene-HT® coating.
Please contact Application support for further information.
Disposal
The TTR 91 N and 96 N transmitters are manufactured according to the RoHS directive.
For the benefit of the environment, at the end of life of the transmitter, it should not be disposed in
the normal unsorted waste stream. It should be deposited at an appropriate collection point or
facility to enable recovery or recycling.
Temperature measurement
resistors Rt
Silicon cover
Silicon cover
Measuring
resistors Rm
Attention
!
Parylene-HT® is a trademark of Specialty Coating Systems, Inc
