Of the wide variety of equipment used by the pharmaceutical industry, vacuum pumps are predominant. They are used in research labs and large-scale production units of bulk drugs, active pharmaceutical ingredients (API) and by intermediates manufacturers. Various pharmaceutical processes, including degassing, vacuum distillation, crystallization, drying, freeze drying and sterilization utilize vacuum pumps. These vacuum pumps ensure high efficiency and low cost of operation by minimizing wear and leakage. The high demands made on vacuum pumps can be optimally fulfilled with the help of RINGFEDER® Locking Assemblies. Read this article to learn how!
Function principle
Vacuum pumps pull out the air and gases from a closed chamber and create a vacuum. They have two screw rotors fitted that rotate in the opposite direction with very minimal clearance. The clearance between these rotors is ensured by the frictional connection between the gears and the rotor shaft. When the rotors continue to rotate against each other, the space volume between them starts to reduce from the inlet to outlet and finally the air or gas is let out through the outlet port when the desired pressure is reached.
The requirement
The significant advantages of dry screw vacuum pumps compared to wet types are high efficiency and very low operating and maintenance costs. The main reason for that is oil-free air; no oil is needed in the system, except where the rotors make contact. Minimal clearance between the rotor lobes and between the rotor and casing is the primary requirement in avoiding leaks between different pressure sides and, additionally, makes the entire system compact. Minimal clearance alone does not help, but a minimal slip of rotor connections plays a vital role, too. However, less clearance in combination with increased run-out of the rotor connection may lead to heavy wear. Slip in the connection will again not deliver the desired output. Only a rotor connected to the shaft having minimal run-out and minimal slip can ensure the desired function of this system.
The solution
An absolutely backlash-free connection is a primary requirement in this case. RINGFEDER® Locking Assemblies are friction-locked shaft-hub connections manufactured to the highest quality standards. They are suitable for the precise fastening of toothed gears that hold the rotor shaft with minimal clearance. Locking Assemblies are installed between the main rotor shaft and the toothed gears. By tightening the clamping screws, the inner and outer rings press themselves onto the contact surfaces of the components to be connected, thus creating a friction-fit press connection. This allows not only the highest torques to be reliably transmitted without slip, but also axial, radial and bending loads.
RINGFEDER® Locking Assemblies are the superior alternative to conventional keyways used in dry vacuum pumps and offer outstanding concentricity and resistance, which are the main features that determine optimum performance and efficiency of the pump.
Other application areas
RINGFEDER® Locking Assemblies enable extremely precise concentricity in the clamped components. The maximum concentricity error for clamping sets that are machined in a clamping process is an extremely low 0.04 mm. These clamping sets are used primarily in gear wheel mountings in rotary pumps and in machine tools that require the highest level of precision.
To learn more about our Locking Assemblies for different applications, visit our website or send us contact request.
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