Shear rate – Shear rate is a term from kinematics. It describes the spatial change of the flow rate in liquids. As there are frictional forces in flowing media, various flow rates at various positions of a liquid also mean that a transmission of energy takes place. The shear rate is used in rheology to define the viscosity. It is the coefficient of proportionality between shear stress and shear velocity. The layered flow in laminary flowing media is observed here. The unit of measurement is s-1. This parameter also plays a big role in the design specification of static mixers as the characteristics of several media may change decisively at high shear rates.
Standard cubic metre – A question which often leads to incorrect calculation results is whether the volumes specified by the customer are standard or operating cubic metres.
The standard volume (particularly standard cubic metres, standard litres, etc.) is a volume unit common in pneumatic, process engineering and gas technology. It is used to compare gas volumes which are present in different pressures and temperatures (operating condition, operating volume). To do this, the gas volumes are converted to the respective standard condition, for instance by using the conversion factor.
As early as 1940, the following standard conditions were defined in DIN 1343 and have become established across the globe under the term “physical standard state”:
– standard pressure pn = 1013.25 hPa = 1.01325 bar
– standard temperature Tn = 273.15 K = 0 °C
The operating cubic metre describes the gas volume which is present under the actually prevailing operating conditions (operating pressure and operating temperature). Under operating conditions, important parameters like density and dynamic viscosity which have to be closely examinated, do change.
Static mixers – Static mixers from STRIKO guarantee continuous operation in closed piping systems. They do not have any movable parts and so are virtually wear-free. All mixer variants from STRIKO are maintenance-free, can be cleaned in-line, sterilised/steamed and slightly detached if required.
Sterile bursting discs – STRIKO sterile bursting discs made of metal are outstanding particularly due to their unique, minimal dead space design on the side in contact with the product – a feature customers from the pharmaceutical or food industry attach great importance to. Sterile bursting discs are usually inserted in Tri-Clamp®-connections. All available versions of sterile discs guarantee a fragment-free opening which is especially important for these types of applications. STRIKO sterile bursting discs are ideal for safeguarding gases, liquids or two-phase flows as well as media tending towards caking. STRIKO sterile bursting discs are available in a multitude of different designs, be it vacuum proof or with integrated burst indication, made of standard or special materials.
Surface roughness – Surface roughness is a term from surface physics and refers to the unevenness of the surface height. The quantitative characterisation of roughness can be determined by means of various calculation methods which take into account the specific properties of the surfaces. The surface roughness can for instance be changed by means of polishing, grinding, lapping, honing, pickling, sand blasting, bristle blasting, etching, vaporising or corrosion.