In the seven decades of its existence, Dynisco has accumulated almost 100,000 different configurations. So how do I choose the right one for me? A sensor is typically defined by the following main specifications:
- Print area
- Process connection
- Electrical output and connection
- Capillary configuration (rigid/flexible)
Typically, the pressure inside a plastics processing machine can be estimated sufficiently to determine a good pressure range for a sensor. The typical working pressure should be between 20% and 80% of the sensor's pressure range to achieve a good balance between accuracy and durability.
Over time, a standard has developed for threaded connections in plastics processing, the ½"-20UNF thread with a conical sealing surface. There may be situations where other thread sizes or a flanged connection are required. Dynisco offers numerous options to meet customer process connection requirements.
A pressure sensor is an electromechanical device that converts a mechanical effect into an electrical signal through a strain gauge (pressure applied to a thin piece of metal). The strain gauge changes its resistance by following the deflection of the piece of metal. In the simplest case, the signal coming from the strain gauge can be used directly to feed a reading device to display the pressure. To match industry standard devices such as process control equipment, Dynisco supplies sensors with various amplified output options such as 4-20mA or 0-10V.
A typical pressure sensor has a liquid-filled capillary that connects the process diaphragm (which is deflected by the process pressure) and the measuring diaphragm (where the strain gauge is bonded). This capillary is necessary to create a thermal barrier, since the strain gauge cannot withstand the typical process temperatures in plastics processing. The electronics of the sensor must also be kept as far away from heat sources as possible. In order to be able to find a good installation location for the electronics, countless combinations of rigid shaft and flexible connection lengths are available.
These four points provide a rough definition when selecting a suitable sensor for plastics production. Other points that are very individual would be:
- Membrane Materials
- Membrane Coatings
- Approvals and Certifications