More than half a century...
supplying measurement and pressure or temperature control instruments has enabled the GEORGIN team of engineers to acquire know-how and experience which are expressed throughout this site, beginning with the wide range of technologies used to provide solutions to each specific problem encountered by their customers.
Instruments for measurement
PRESSURE TRANSMITTERS
The principle used by GEORGIN for their product manufacture is the piezo-resistive effect sensor : under the effect of pressure, a distortion provokes proportional variations in a resistance bridge which are converted into an electric signal.
At present, two types of gauges are used : • Silicium semiconductor strain gauges
• Strain gauges with thick layer plating onto a ceramic support which ensure long life and excellent resistance to corrosive environments.
TEMPERATURE TRANSMITTERS
An electronic module converts the signal transmitted by the probe into an analogue signal. Two types of probes are used : • Thermocouples which generate a voltage (mv)
• RTD which vary according to temperature.
Instruments for control and safety
PRESSURE - TEMPERATURE SWITCHES
The pressure or temperature to be controlled is applied to a sensor (diaphragm, bellows, manometric tube). Whenever there is a change of pressure or temperature, the sensor is distorted and acts on a force balance connected to a microswitch.
Opposite this sensitive element, an adjustable spring enables the working point to be adjusted : whenever the pressure on the sensor is sufficient to counter the spring pressure, the force balance changes position.
Adding a second adjustable spring permits greater or lesser increase of the hysteresis (dead-band) or to act on dislocation between the two contacts if the instruments is thus equipped.
MEASUREMENTS UNITS :
From a single box per serie (a number of series are available) one of the measuring units described below is adapted to the customer's particular application.
Relative pressure
• Bellows :
The most conventional sensitive element used in our pressure and temperature switches is a metallic bellows (bronze or stainless steel) made up of a corrugated tube fitted with two airtight rigid ends. Flexible by nature, it compresses or elongates axially under the effect of pressure and provides excellent transmission.
• Diaphragm :
For low pressure, bellows which are too rigid are replaced by an elastomer diaphragm which is hold in place by two metal plates. "Diaphragm" technology is also used in cases of excessively high pressure and pulsating phenomena.
• Manometric tube :
For very high pressures, the sensor used is a stainless steel tube curved into a C shape which is closed at one end and which changes position under the effect of pressure.
Differential pressure :
A differential pressure switch is fitted with two connections : one of them (HP) is connected to the highest pressure, the other (BP) to the lowest pressure which means, in the majority of cases, that it has to be fitted the right way round. These two connections correspond either to two sets of bellows fitted opposite one another or to the two sides of the diaphragm. The resultant of the two different pressures acts on the internal mechanism which then functions like a standard instrument.
Absolute pressure
The pressure switch is fitted with a differential measuring element with bellows, one of which is vacuum sealed so as not to be affected by atmospheric pressure.
Temperature
GEORGIN uses steam pressure law for their temperature switches : a liquid under pressure is enclosed within a vessel. Under the effect of heat, the temperature is transformed into pressure inside the bulb and is thus transmitted to a mechanical bellows converting this pressure into a force. This process has the advantage of not being influenced by ambiant temperature.
Two types of bulbs are used :
• The directly connected bulb,
• Capillary bulb allowing an installation away from the sensor.
Instruments for control and safety
Electrical safety provided by GEORGIN concerns industrial sites equipped with electrical systems where the formation of an explosive atmosphere is possible.
Several protection methods can be used for instrumentation installed in those hazardous areas with a high risk of explosion. GEORGIN offers its customers 3 of these methods, i.e. explosion-proof enclosures, increased safety and, in particular, intrinsic safety.
The latter is based on the principle of the "intrinsic safety electric circuit" as defined by the CENELEC European norm, as being "a circuit within which no temperature effect produced under the test conditions prescribed by the norm may cause the outbreak of fire in a given explosive environment".
There are two types of circuit :
Equipment known as "intrinsic safety equipment" destined to be placed in hazardous area (sensor, circuit indicator, flash-light indicator).
Equipment known as "associated equipment" where only circuits in direct contact with the hazardous area are intrinsically safe, and which are located in the safe area (signals conditioners, power supply...)
An intrinsic safety circuit can be designed in two ways :
Either completely earth insulated, called "galvanic insulation" ,
Or earth referenced, the so called "Zener barriers".
GEORGIN offers both solutions to their customers thus allowing them to make their choice.
If equipment design allows safety to be maintained even in the presence of a combination of two failures, it is considered to belong to the category known as "ia".
If it remains safe in the presence of a single failure, it is considered to belong to category "ib".
Throughout its site, GEORGIN offers category "ia" equipment which can be used in any area and in particular in hazardous areas with permanently dangerous conditions where only equipment meeting I.S. standard "ia" is permitted for use.
The principle used by GEORGIN for their product manufacture is the piezo-resistive effect sensor : under the effect of pressure, a distortion provokes proportional variations in a resistance bridge which are converted into an electric signal. 
The pressure or temperature to be controlled is applied to a sensor (diaphragm, bellows, manometric tube). Whenever there is a change of pressure or temperature, the sensor is distorted and acts on a force balance connected to a microswitch. 
