Compact pressure transducer reduces downtime through high stability
10 August 2006
The 3100 series of thin film metal pressure transducers from Gems Sensors & Controls offers very high stability, reducing downtime and saving engineering resource. The unit features a very small package size, as little as 25mm in length, significantly smaller than other sensors. This in turn allows oems to reduce the size of their own products.
The stainless steel sensor of the 3100 is welded to a pressure port using a gas laser weld technique that gives a high strength, fatigue-free joint. Both components of this simple two-piece construction are manufactured from high-strength precipitation-hardened stainless steel, ensuring a durable construction and mechanical integrity. The thin film gauges are deposited on to the diaphragm surface using sputtering techniques, which helps to eliminate drift and ensure repeatable performance. As a result, long-term stability is believed to be 3-4 times better than transducers that are based on traditional technology.
Long term drift for the series is 0.1% of full scale per year non-cumulative. This eliminates recalibration, which can be required every 6-12 months on other sensor types, taking up to 30 minutes per sensor. This saving in downtime and engineering resource can be significant when added to the cost of the unit. The all-welded construction also eliminates leakages which can occur on sensors which use o-ring seals, and means that the sensor itself is very robust.
The 3100 covers a very broad pressure range, from 10 up to as high as 2200 bar. This means that manufacturers can use same model type for different applications. For example, medical gas distribution measures bottle pressure at 250 bar and line pressure at 16 bar. Both ranges are available in the3100 series with the same accuracy and stability.
Operating temperatures for the units can be as high as 135ºC, making the 3100 a very cost effective option for high temperature applications.
The thin film gauges are electrically isolated from the diaphragm surface by a layer of silicon dioxide, whilst the sensing element is wire bonded to the pcb by aluminium wire with bond strength not less than 150 grams, offering the benefit of improved cyclic pressure reliability. The unit is constructed with a single PCB which also incorporates filtering and transient suppression components. This provides both a high level of RFI protection and resistance to voltage spikes.
3100 sensors are available with a choice of 6 electrical connections and 9 pressure ports, which means that the unit is suitable for most applications without modification. In many cases existing sensors can be replaced without any need for re-engineering.
Within the range, the 3200 heavy duty pressure transmitter features a thicker diaphragm, and a pressure snubber, a small orifice which directs pressure away from the sensor surface, thus enabling the unit to withstand the rigours of cavitation or extreme pressure spikes - very important in mobile hydraulics.
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