The Void Turbo Coupling is hydrodynamic coupling based on Foettinger’s Principle. Its main components are two bladed wheels – as wheel as an outer shell. Both wheel are positioned relative to each other. Power transmissions is achieved with minimal mechanical wear and there is no mechanical contact between the power transmitting component

The coupling operates on a constant quantity of operating fluid, usually mineral oil. On demand, design for water is available. The torque transmitted by the drive motor is converted into kinetic energy of the operating fluid in the pump wheel to which the motor is con¬nected. In the turbine wheel, this kinetic energy is converted back into mechanical energy. Three operating modes are defined:

Standstill The entire operating fluid in the coupling is at rest. Start-up With increasing speed, the oper­ating fluid in the working circuit is accelerated via the pump wheel. The circulatory flow created in this way is supported by the turbine wheel and sets the latter in motion. The torque development is deter­mined by the characteristic curve of the coupling, while the start-up characteristics are influenced by an appropriate arrangement of compen­sating chambers (delay chamber, annular chamber). Nominal Operation The low speed difference between pump and turbine wheel (the so­called nominal slip) leads to the flow condition in the coupling becoming stationary. Only the torque required by the driven machine is transmitted

 

Essential design factors for a fluid coupling are the power and motor speed. having established the nom­inal power and speed required, the diagram on the right enables deter­mination of the appropriate size of the coupling.
Different conditions require different starting procedures (characteristic curve) for the coupling. Important criteria in this respect are the mass moment of inertia, torque limitation and frequency of start-ups.

 

 

Turbo Coupling Type T is the basic version of constant-fill couplings, consisting of pump wheel, turbine wheel and outer shell. A further range has been created by the addition of other parts to this basic type.
The fluid coupling is normally mounted on the machine shaft or gearbox shaft to be driven (outer wheel drive). In order to compen­ sate for any slight installation inaccuracies, a flexible connecting coupling is used to join the coupling and input shaft. Use of this type of fluid coupling is damp­ing and overload protection are required for motor and driven machine; they may also be used for simpler transmission systems in the lower performance range.

The coupling Type DT has two coaxial work circuits operating in parallel. By means of a double circuit the output of the same size.

Applications:

• Bucket-wheel excavators
• a Bucket-wheel elevators
• Mixing, kneading and stirring machines

The TV version features a "delay-fill chamber" which is flange-connected to the outer wheel of the coupling. At stand-still, a proportion of the work­ing fluid lies in this chamber, thus reducing the volume in the working circuit. Hence on motor start-up, a reduced coupling torque is transmit­ted, whilst simultaneously providing an unloaded motor start. After the motor has run up, the working fluid flows from the delay-fill chamber into
the working circuit which smoothly accelerates the driven machine up to its operating speed. Furthermore, if the application so demands, the delay-fill chamber can be further enlarged (Type TVV), thus enhancing its effects and fur­ther reducing the coupling torque on motor start, as well as resulting in even longer and smoother start up of the driven machine.
In certain cases, the function of the delay chamber can be additionally improved through centrifugally con­trolled valves (Type TVF) or through hydrodynamic refill (Type TVY).
Belt conveyors

• Centrifuges, decanters
• Tube Mills

• High-media machines
• Crushers

 

The TVVS is a further Voith devel­opment in cooperating an annular­chamber shell in addition to the en­larged delay chamber. The additional chamber in the cou­pling shell enables further reduction of the starting torque. During the in­itial rotations of the start-up proce­dure, centrifugal forces normally cause the outer chamber of the cou­pling to be completely filled with op­erating fluid from the working circuit.
In comparison with couplings with­out annular chamber, filling of the working circuit of a TVVS Coupling is considerably reduced, which, in turn, lessens the torque transmitted during motor run-up. The increase in torque then follows a gradual emptying of the fluid from the delay chamber into the working circuit.
The starting procedure can be adap­ted to the requirements of the appli­
cation by adjustable nozzle screws diameters.
This new concept for couplings was designed originally for conveyor belt drives. Through the gradual build up of torque an automatic adaptation to belt load conditions is achieved.

 

• Belt conveyors
• High-inertia machines

 

The V-belt or flat belt pulley which is mounted to the bearing cover allows various transmission ratios to be ac­commodated. If required, the pulley may be easily changed. TRI and TVRI type Turbo Couplings are normally installed on the motor shaft in an overhung position. The belt force is supported by a bearing in the bearing cover on the coupling hub. TRI couplings can be installed both as start-up device and overload protection. Type TVRI with additional delay chamber is recommended if a particularly smooth start-up is

 

 

• Centrifuges and decanters
• Fans
• Mixers
• Crushers

  

MTS Mechanical Termal Switch

As protection against overheating, fusible plugs are a standard feature. In order to avoid loss of operating fluid through thermal overload, a mechanical thermal switch (MTS) can be added. On achieving the re¬sponse temperature, the element activates a pin which then operates a switch. Depending on the type of circuit, the signal can be used either as an alarm or to switch off the motor. The circuit element has to be re¬placed after activation. Monitoring of coupling temperatures takes place without any contact. After activation of the switch, no re¬placement of the element is re¬quired. It is ready for use as soon as the coupling has cooled down. The signal can be used either as an alarm or to switch off the motor.

  

Mounting and removal device

Required for professional, safe installation and removal.
As well as the mechanical tool, a hydraulic removal tool is available.
By fitting a sight glass, the fluid level in the coupling can be easily checked without opening the coupling.