Innovative pressure sensor for plastic extrusion

The HARSHMAX optical pressure sensor is designed to allow measurements of pressure for different applications. It was born from the experience of Laser Point R&D, applying the criteria and technologies of laser measurement to new areas, such as optical sensing of physical parameters like pressure.

The HARSHMAX optical pressure sensor works according to a totally new patented principle in which no mechanical part is in relative contact.
No poisonous means of transmission (e.g., mercury or oil) are used, resulting in an intrinsically safe device, ideal for all materials, including food and medical products.

Since the pressure signal is an optical signal transmitted via optical fiber, the sensor head can be installed virtually hundreds of meters away from the signal processing box, making installation simpler and smoother. In addition, the sensor head can be easily replaced in case of diaphragm wear or if a different full scale is required for a new extrusion process. The head is designed to operate reliably at high temperatures, so it can be placed directly in contact with extruded materials without the need for the aforementioned pressure transmission parts such as oil, mercury or push rod. This is done without compromising accuracy and hysteresis.

APPLICATIONS
The HARSHMAX pressure sensor (HPS) is primarily designed for use in extrusion or compounding machines where melt conditions are mandatory for a reliable and consistent process. The measurement of melt pressure and temperature, when connected to the machine control system, greatly improves the consistency of the production. It also acts as a protection for the equipment against high pressure bursting or mold breakage.

Furthermore, as there is no contaminating material inside the sensor head (such as mercury, oil etc.), it is ideal for applications such as medical products and food packaging.

HARSHMAX key specifications and advantages are:
- Patented (granted in US, Canada, Europe, Brazil, China, Japan): pressure measurements performed by optical means without contact between internal mechanical parts, allowing no mechanical stress for superior reliability; 
- Eco-friendly: fully RoHS compliant, no need for mercury, oil or other toxic elements, typically found in piezoelectric sensors;
- Passive head: no electronics inside the sensor head for better reliability; the head is made of stainless steel and optical fiber, all suitable for operation in HARSH environments with high temperature and high pressure conditions (up to 1 kBar, up to 300°C). Insensitive to Electro-Magnetic Interference (EMI); 
- Remote electronics: an Optical Fiber is used to transmit the pressure signal far from the HARSH environments such as extrusion machines. Electronics can be placed in a safe distance up to dozens of kilometers from the sensor head; 
- Low maintenance cost: thick deformable pressure sensing diaphragm allows for longer operating lifetime. Absence of toxic materials in the sensor head guarantees no contamination in the extrusion chamber. No need for electronics replacement when changing the sensor head.

For further information www.harshmax.com or [email protected]