"Krystal Bond™ Technology is the latest MEMSMicro Electro-Mechanical System pressure sensor technology. Using a single piece of metal and MEMS strain gages, this technology provides accurate, repeatable measurements." - Karmjit Sidhu, Vice President Business Development, AST Co-Founder, and Material Science PhD candidate at the New Jersey Institute of Technology (NJIT).
The strain gages are molecularly diffused onto the metal diaphragm surface using inorganic materials and high temperatures. As the temperature is reduced, the inorganic bonding material solidifies and secures the silicon strain gauge into position above the center of the sensor, thus creating the one piece sensing element.
With an operating strain at less than fifteen percent (15%) of the metal's yield point, pressure sensors using Krystal Bond™ Technology have less fatigue, higher proof/burst pressure capability, and excellent long term stability. A simple example of this is inflating and deflating a balloon several times. The stretching and distortion depends on the thickness of the balloon. The principles of pressure measurement are the same. As a diaphragm is pressurized closer to the yield point, a transformation in the shape occurs, changing the output over time. Krystal Bond™ Technology would be similar to inflating the tires on a bicycle or car with the same method.
By using inorganic materials in the process bonding the strain gages to the diaphragm, there is virtually an infinite shelf life to the pressure sensing element. AST's strain gages also yield a high output signal with low thermal errors. For certain applications, AST can create solutions with extremely high proof and burst pressure ratings. Pressure transducers and transmitters are available with pressures up to 60,000 PSI (4,000 bar).
The typical pressure sensor includes a threaded process connection, hex or flats for installing the thread and a diaphragm. For sensors with Krystal Bond™, all three components are a single element. A bar of metal has the outside shape machined and the inside hole bore. The liquid or gas is completely contained within the sensing element's process connection. Other sensor technologies can clamp a ceramic diaphragm with an O-ring, use an oil-filled cavity to transfer pressure, or weld a diaphragm onto the process connection. Krystal Bond™ simplifies any system design with one material and no leak paths. By designing the pressure sensor with one piece of material, AST has eliminated weak points and contamination risks.
Sensors with Krystal Bond™ Technology are designed with high electrical isolation and low leakage rates at 500VAC, making it ideal for process control applications, including CSA certification.
Krystal Bond™ Technology can be used on a variety of materials including 17-4PH, 316L, Inconel718, Hastelloy C276 and Titanium, which are designed in different package sizes to meet customer demands. From sour gas in the oil patch to medical pumps in the human body, our MEMSMicro Electro-Mechanical System technology can be matched to a variety of liquid and gas requirements.
For pressure ranges of 15 PSI and below, AST utilizes a stainless steel diaphragm with silicone oil-filled pressure sensor to compliment Krystal Bond™ Technology. LP technology enhances AST's ability to offer a complete range of solutions, with gauge and bi-directional pressures as low as 1 PSI. LP technology sensors are approved for explosion-proof, intrinsically safe and non-incendive areas for pressure and level measurement and offer accurate, stable output signals. Although not suitable for hydrogen, LP sensors are available with 316L stainless steel or Hastelloy C276 material.