Setra Blog

Hysteresis Defined

According to Merriam-Webster, hysteresis is the “lagging of a physical effect on a body behind its cause (as behind changed forces and conditions)”. When outside forces act on an object, that object will either immediately spring back to its original state, or more likely, it will somehow change or exhibit properties from previous deformations.

When first selecting a pressure transducer for a new project or piece of equipment, designers typically focus on key design parameters such as pressure range, electrical output, media compatibility and environmental conditions.  However, those parameters are not the only ones to consider when making a smart choice for an application. There are three design considerations that are often overlooked when selecting a pressure transducer: transfer medium (oil filled vs. non-oil filled), construction, and type of sensing technology.

Did you know that companies spend hundreds of millions of dollars on research and development for off-highway vehicle engines? A portion of the R&D goes into developing specialized engine test stands to ensure that the engines are functioning properly.

Stainless steel (SS) comes in all shapes, sizes, and compositions. It’s an alloy comprised of several different elements such as iron, nickel, and chromium with superior corrosion resistance compared to its constituent parts. Different applications require different material properties. In fact, there are dozens of individual grades of stainless steel alone, each with a unique proportion of ingredients, benefits, and . This article will focus on two types in particular: 17-4 and 316L stainless steel.

What is Water Hammer?

Water hammer is shock wave produced by the sudden stoppage or reduction of a fluid flow. This can cause sudden rises in pressure and damage instrumentation. In tank level measurement applications, high pressures can be generated by the sudden closure of a valve on an outlet line. Although it might seem to be a consistent flow, the water inside pipes tumbles as it moves through.

1. Pressure

The first and most important consideration is pressure. A number of questions must be answered to ensure the correct transducer is selected. What is the pressure range that the transducer will measure? What is the maximum pressure the transducer will encounter? What is the potential for over pressure in the system?

Pressure transducers today are more rugged and reliable than ever. Made of stainless steel construction, they provide abundant overpressure protection, improved total error band, and offer negligible orientation and vibration effects. They are ideal for long-term use even in harsh environments of extreme temperature, humidity, and vibration.

The accuracy of differential pressure transducers has greatly improved to provide better solutions for demanding applications. This article discusses why accuracy is an important consideration when selecting a pressure transducer for low-differential, critical pressure applications.

Can’t handle the pressure?

Can you believe that pressure transducers are not always able to handle high pressure? Overpressure, or proof pressure, is a major concern for engineers and OEM designers when assembling machinery and selecting a pressure transducer. Overpressure refers to the maximum pressure value a transducer can withstand without affecting performance; it can also refer to a situation where the pressure value exceeds the limits. Although it is not ideal, pressure transducers can withstand occasional pressures up to their overpressure rating, eventually returning to their natural state. However, pressures that reach burst pressure, the maximum pressure that may be applied to the positive pressure port without physically damaging the internal sensing component, can rupture the diaphragm and cause leakage. Pressures above overpressure but below burst pressure can result in permanent diaphragm deformation, causing an output shift affecting operational performance or accuracy readings.

Below are terms that are associated with use of transducers and electrical equipment in areas which are defined as hazardous by national rating agencies.