Flanged shaft couplings – find manufacturers and suppliers

Flange coupling

A flange coupling is a rigid coupling with no compensation.
A flange is a component used to close, connect and seal machine parts (housings, nuts, bolts, etc.). However, flanges also position parts. In addition, they are used to transmit operating forces.
Coupling means a machine element for the detachable, movable, elastic or rigid connection of two shafts. This connection can be either non-positive or positive.

Shaft couplings are used whenever torque is to be transmitted from one element to the shaft end or from shaft end to shaft end. They also compensate for misalignments. Shaft couplings are differentiated according to the function and type of torque transmission

• Flange couplings are rigid couplings without compensation.
• Metal couplings are torsionally stiff couplings without torsional angle compensation.
• Flexible pin couplings are flexible couplings with torsional angle compensation.

Flange couplings are rigid connections between two shaft ends. They do not compensate for misalignments. The purpose is purely to connect the shafts and to separate them in the event of repair. The attachment of a vertical shaft, such as an agitator shaft, is another possible application. This is mounted to the drive with a rigid coupling.

Flange couplings are mainly used in mobile machines. They form the connection between the elements of the drive. If it is a hydrostatic drive, the flange coupling directly couples the hydraulic pump. In addition, it is used to directly drive the compressor unit in mobile compressors.

This type of coupling can be separated directly at the flanges. Pressing the flange hubs onto the shafts creates a backlash-free connection. Both torsional and bending moments as well as axial forces can be transmitted. The shrink connection only provides the necessary forces, but is not itself integrated in the force flow.

How is the assembly carried out?

Flange couplings are usually supplied ready for installation and are clamped on site using conventional screwdriving tools or hydraulic clamping tools. The functional surfaces of the threads, cones as well as head rests of the bolts are lubricated ex works.
Different types of flange couplings at a glance!
The torsionally elastic connection between a driven machine and the combustion engine is often made by an axially plug-in, highly flexible flange coupling.

Advantages of this connection

With linear torsional spring characteristic there is a very high torsional elasticity. The torque is transmitted backlash-free. These are available in many different designs. The size range usually covers 200 Nm to 110,000 Nm. Plug-in assembly is easy to perform with large length compensation. Larger misalignments can be easily compensated. Torque limitation protects the drive against overload. EC Directive 94/9/EC (ATEX 95) regulates explosion-proof use.

Flange coupling halves FKHA are available for shaft diameters from 95 to 320 mm. The transmittable torque is between 17 and 800 kNm. Flange couplings FKH can be installed for shaft diameters between 70 and 350 mm. Here the torques are between 6 and 911 kNm.Flange couplings FK-HYD are used for shaft diameters between 120 and 440 mm. The transmittable torques for this variant are between 40 and 2,300 kNm. The flange halves are clamped hydraulically.

Interesting facts about flange couplings

Due to the large number of different designs, which are, however, mainly installed in pressure equipment, the mandated and harmonised standard for the Pressure Equipment Directive 97/23/EC is applied in principle. In addition, DIN EN 1092-2 applies to PN 10 flange connections. Of course, the DIN standards for the respective flanges used also apply. Outside diameters and dimensions can be found in the respective data sheets and the relevant standard. Stainless steel or carbon steel versions are the most common.

Straight flange couplings must be robust, resistant and durable. Therefore, special attention must be paid to high-quality workmanship and materials. Regular, proper maintenance of the machine as well as machine parts is a basic requirement for optimum operation and satisfactory results. Flange couplings are in continuous operation and are susceptible to damage. These must be repaired immediately, as minor damage may cause a stoppage of operation.

The after-sales service of the most common manufacturers usually reacts quickly and without complications and is available for advice and assistance (cooperation with other manufacturers in case of delivery bottlenecks!). Flange couplings can be manufactured on request and according to drawings. For this, of course, the specifications of the existing construction and machine elements are required. Sometimes a visit on site is advisable to get a better idea of the plant. This serves to be able to submit possible alternative proposals (cooperations) as well as solutions other than those envisaged.