Application —  12th Aug 2020

Smooth Compressor Applications – eliminating speed restrictions with Geislinger technology

Talking about torsional vibrations, many people have just combustion engines in mind. However, when using reciprocating compressors, quite similar vibration issues apply. Reciprocating compressors are well known for their efficiency and price-performance ratio. With adapted dampers, the equipment can be designed to minimize torsional and lateral introduced forces. Geislinger damper and couplings minimize torsional vibrations and eliminate speed restrictions for compressors. To achieve this, the damper must be designed specifically to reduce residual and localized shaking forces as well as high levels of vibratory torque.

One option to exceed the operating speed range is the use of the Geislinger Steel Spring Damper. It is the most efficient solution for the reduction of vibratory amplitudes. It can be tuned specifically to minimize critical frequencies of torsional vibrations in the operating range. The design of the springs and the mass of the outer part are tailored according to the customer’s system needs. Damping is achieved by pumping oil through narrow gaps inside the damper. The steel springs provide a linear stiffness and the pressurized oil supply provides a very high damping factor as well as a permanent cooling of the damper. This combination enables Geislinger to provide a damper that offers the lowest total cost of ownership for such systems. The design of a steel spring damper is shown in the following figure.

Figure 1: Insights of a Geislinger Steel Spring Damper
Figure 1: Insights of a Geislinger Steel Spring Damper

A second option to exceed the operating speed range of a compressor is the use the Geislinger Viscous Damper (Vdamp®). It offers an alternative for systems where no pressurized oil supply is available. As shown in the following figure, the Vdamp® consists of a free inertia wheel enclosed in a housing surrounded by a high viscous fluid. Damping is generated as the inertia wheel rotates and vibrates in the housing and shears the fluid. Viscous dampers have non-linear properties that are frequency and amplitude dependent. Geislinger takes special care of this behaviour by using its own high sophisticated torsional vibration software.

Figure 2: Insights of a Geislinger Vdamp®
Figure 2: Insights of a Geislinger Vdamp®

In addition to a damper, a flexible but torsional rigid Geislinger disc coupling or a Geislinger torsional elastic coupling can be used between engine and compressor.

The operating speed range can be exceeded by either of these damper types. The following graphic shows the behaviour of such a tuned absorber with the resulting inertia, spring stiffness and damping.

Figure 3: Typical reduction of torsional vibrations using Geislinger Dampers
Figure 3: Typical reduction of torsional vibrations using Geislinger Dampers

Thus, with such powertrain solutions, critical compressor modes can be eliminated. In one application, a combination of a Geislinger damper and coupling avoided a barred speed range of a compressor between 570 and 650 rpm (6th harmonic interference), hence offering a much wider operation range.

Typical applications for compressors optimized with Geislinger technology are gas pipeline transport and storage (midstream) with torsional dampers for reciprocating compressors and torsional elastic or misalignment couplings on compressor stations. The booster stations are powered with 12- and 16-cylinder variants of gas engines and electric motors.

Another typical field is gas processing / refining (downstream) with misalignment couplings for electrically driven compressors and torsional elastic couplings for electrically driven compressors. Practically, the design looks as follows:

Figure 4: Geislinger BC 90 Dual Coupling installed between an Engine and a Compressor
Figure 4: Geislinger BC 90 Dual Coupling installed between an Engine and a Compressor

To avoid barred speed ranges and thus improve the operating speed range, Geislinger products are the ideal solution for gas compressor and reciprocating compressor applications due to their ability to operate in harsh conditions and still maintain a long-life expectancy. The Geislinger steel spring couplings and dampers show no aging with constant properties and consistent behavior that offer the lowest total cost of ownership. Geislinger compressor solutions – built to last.