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Voith Turbo Variable-Speed Turbo Couplings
Application Examples of Voith Variable-Speed Turbo Couplings
Power Plants
- Fans
- PumpsRaw Materials Processing
- Transport technology
- Mining
- Processing TechnologyChemical Industry
- Pumps/Fans
- Mixing Equipment/CentrifugesDistrict-Heating Plants
- Circulation Pumps
Marine Technology
Petrochemical Industry
- On-/Off-Shore
- PipelinesMetallurgical Industry
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The Various Types and their Fields of Application
Performance Characteristics For all Types
Our Experience
The question posed to today's technicians is not so much whether a problem can be solved, but rather how it can be solved. Admittedly, there are many solutions for the design of power transmission systems. 60 years ago, we at Voith decided upon what we felt is the best and, at the same time, the most versatile solution ... hydrodynamics.
Based on this wealth of experience, Voith engineers have been able to expand their knowledge - knowledge from which your company can benefit. Where smooth, controlled acceleration and deceleration are required, the advantages of hydrodynamics and the name connected to it ... Voith, will sooner or later be pointed out.
You can be certain that we have already developed a solution to your power transmission problem somewhere in the world - with Esprit, Excellence and Effizienz -the key attributes of our company.
"Learning by doing" has always been our motto. Only those units which were operating day after day under the most arduous conditions could be optimized effectively. This is why our variable-speed turbo couplings have reached a standard of quality which can hardly be improved.
The main fields of application include: control of boiler feed pumps and circulation pumps in conventional and nuclear power plants as well as district heating plants, control of engineering processes in chemical and extraction plants, centrifugal and piston pumps (slurry pumps), ventilator units and compressors, frequency converters for sodium pumps in nuclear power plants, crushers (coal, hammer and impact crushers), mixers, agitator units, centrifuges, conveyor drives, pipelines, etc.
Voith variable-speed turbo couplings - our experience to your benefit.
Operation
The Voith variable speed turbo coupling is a fluid coupling which transmits the energy input by the mass forces of a fluid which is circulated in a closed system between an impeller on the driving (primary) shaft and a runner of similar design on the driven (secondary) shaft.
The section drawing shows the typical form of the coupling blade arrangement and the layout of the impellers in the working area.
In contrast to the constant-fill type turbo coupling, the oil filling of the variable-speed turbo coupling can be varied between completely filled and drained while in operation. In this way, infinitely variable speed control of the driven machine is achieved over a large range when the coupling operates against the load characteristics. This control range is dependent upon the load characteristic (torque relative to speed) and the required governing accuracy.
The working oil circulation is maintained by a continuously running pump which delivers oil from the integral sump below the coupling into the working compartment. The working compartment is the chamber between the primary (impeller) and the secondary (runner) wheels which is connected to a rotating scoop chamber consisting of an inner and an outer shell. The amount of oil in the working compartment determines the speed at the output side of the coupling and is dependent upon the radial position of a scoop tube located in the scoop chamber. The flow capacity of the scoop tube far exceeds the pump delivery; thus, with respect to control and governing, reaction times are held to a minimum.
The grades of hydraulic oils recommended for use in operation are specified in the Operating Instructions.
Depending on the application, the operation of the scoop tube can be either manual or automatic with the use of an operating mechanism which can be integrated into the control system. Completely assembled actuator and control equipment are normally included in delivery. The heat generated by the slip losses is dissipated by a heat exchanger, should the cooling capacity of the turbo coupling itself prove insufficient.
Variable-Speed Turbo Coupling Type SVTL
The coupling type SVTL is a self-supporting design of tunnel construction. The rotating parts are supported in a sealed, oil-tight housing. The main motor and the driven machine are linked to the turbo coupling via shaft couplings. The oil tank is integrated into the housing and the oil pump is driven by the input shaft by a set of gears.
The main shaft is supported on roller bearings lubricated by pressurized oil.
Simplified longitudinal section
1 Primary wheel
2 Secondary wheel
3 Shell
4 Scoop tube housing
5 Oil sump
6 Oil pump
7 Scoop tube
Performance characteristics variable-speed turbo coupling type SVTL
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The variable-speed turbo coupling type 487 SVTL driving a blower unit.
Covers for rotating parts are removed for demonstration.
Type SVTL Dimensions in mm
| Size | A | B | C | Oil requirement |
Weight |
| 366 | 973 | 500 | 1490 | 110 | 530 kg |
| 422-22 | 973 | 500 | 1490 | 110 | 550 kg |
| 422-22-2 | 1120 | 630 | 1780 | 250 | 750 kg |
| 487-21 | 973 | 500 | 1490 | 110 | 570 kg |
| 487-22 | 1145 | 630 | 1780 | 250 | 735 kg |
| 487-12 | 1255 | 800 | 1780 | 500 | 970 kg |
| 562 | 1145 | 630 | 1780 | 250 | 800 kg |
| 562-12 | 1255 | 800 | 1780 | 500 | 1010 kg |
| 650 | 1310 | 750 | 2000 | 300 | 1050 kg |
| 750-6.3 | 1310 | 750 | 2000 | 300 | 1150 kg |
| 750-10.2 | 1469 | 725 | 1400 | 400 | 1650 kg* |
| 866 | 1469 | 725 | 1400 | 400 | 1700 kg* |
* In this type, the oil tank extends into the base, causing Dimension B to be exceeded.
Dimensions subject to change without further notice.
Variable-Speed Turbo Coupling Type SVNL
The coupling type SVNL is of self-supporting design with a horizontally divided housing. The rotating parts are supported in a completely enclosed, oil-tight housing. The main motor and the driven machine are linked to the turbo coupling by means of shaft couplings.
The oil tank is integrated into the housing and a centrifugal pump serves as the oil pump (in certain versions, a gear pump is used), which is driven by the input shaft by a set of gears.
The main shaft is supported on roller bearings lubricated by pressurized oil.
Simplified longitudinal section
1 Primary wheel
2 Secondary wheel
3 Shell
4 Scoop tube housing
5 Oil sump
6 Oil pump
7 Scoop tube
Performance characteristics variable-speed turbo coupling type SVNL
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The variable-speed turbo coupling type 562 SVNL driving a circulation pump.
Type SVNL Dimensions in mm
Size A B C Oil
requirementWeight 562-33 1358 630 1600 750 1700 kg 750-22 1750 850 1500 500 2050 kg 866-22 1750 850 1500 500 2200 kg 866-22-26 1750 1060 1820 1000 2800 kg 1000-21 1950 1060 1920 780 3650 kg 1000-22 1950 1060 1920 780 3850 kg 1150-21 1950 1060 1920 780 3800 kg 1150-22 2170 1060 1920 780 3850 kg 1210-21 1950 1060 1920 780 4000 kg Dimensions subject to change without further notice.
Variable-Speed Turbo Coupling Type SVNLG
The coupling type SVNLG is of self-supporting design with a horizontally divided housing. The rotating parts are supported in a completely enclosed, oil-tight housing. The main motor and the driven machine are linked to the turbo coupling by shaft couplings.
The oil tank is integrated into the housing and a centrifugal pump serves as the oil pump, which is driven by the input shaft by an auxiliary take-off.
The main shafts are supported on friction bearings, the smaller sizes (487-1150) are built with a roller bearing as relative bearing. All bearings are lubricated by pressurized oil. An electrically driven auxiliary oil pump for pre-lubrication is installed for startup purposes.
Simplified longitudinal section
1 Primary wheel
2 Secondary wheel
3 Shell
4 Coupling housing
5 Scoop tube housing
6 Oil sump
7 Scoop tube
8 Oil pump
9 Auxiliary lubrication pump
Performance characteristics variable-speed turbo coupling type SVNLG
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The variable-speed turbo coupling type 650 SVNL driving a centrifugal pump.
Type SVNLG Dimensions in mm
Size A B C Oil
requirementWeight 487-33 1358 800 1600 430 1600 kg 487-33 1358 630 1600 750 1820 kg* 562-33 1358 800 1600 430 1600 kg 562-33 1358 630 1600 750 1900 kg 620-33 1485 900 2160 430 3600 kg 682-33 1485 900 2160 430 3800 kg 1330-12 3150 800 2400 1500 12000 kg 1330-21 3150 800 2400 1500 10000 kg 1390-21 3150 800 2400 1500 11000 kg 1540-21 3150 800 2400 1500 12000 kg 1780-21 3780 900 2900 3000 16200 kg Information about sizes not listed in the table above upon request.
* In this type, the oil tank extends into the base, causing Dimension B to be exceeded.
Dimensions subject to change without further notice.
Variable-Speed Turbo Coupling Type SVL
The coupling type SVL is of self-supporting design with a high power density. The input and output shafts are each supported separately in cast housings. The main motor and the driven machine are connected to the turbo coupling by shaft couplings.
The oil tank is integrated into the housing. There are two oil circuits: work oil and lubricating oil. Both are operated by mechanically driven pumps. A valve controls the working oil flow, thereby conserving energy.
Simplified longitudinal section
1 Primary wheel
2 Secondary wheel
3 Shell
4 Coupling housing
5 Oil sump
6 Oil pump
7 Scoop tube
8 Flow control valve
9 Auxiliary lubrication pump
Performance characteristics variable-speed turbo coupling type SVL
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The variable-speed turbo coupling type 562 SVL driving an offshore crude oil pump.
Type SVL Dimensions in mm
Size A B C Oil
require mentWeight 422 1275 625 1020 450 1200 kg 464 1305 650 1076 500 1320 kg 510 1408 700 1110 600 1430 kg 562 1465 750 1125 650 1750 kg 620 1708 800 1270 700 2800 kg 682 1900 900 1330 900 3350 kg Dimensions subject to change without further notice.
Variable-Speed Turbo Coupling Type SVNL vert.
The coupling type SVNL vert. is self supporting and vertical in design. The rotating parts are supported either completely within the housing or by the main motor on the pinion end. Depending on the type of machine to be used, the pinion end and the takeoff side of the housing are adapted accordingly.
The oil supply is controlled by a separate oil system equipped with electrically driven oil pumps.
Depending on the size and intended application, variants with roller bearing support or with friction bearing support are available.
Performance characteristics variable-speed turbo coupling type SVNL vert.
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The variable-speed turbo coupling type 650 SVNL vert. driving a waste water pump.
Simplified longitudinal section
1 Primary wheel
2 Secondary wheel
3 Shell
4 Scoop tube housing
5 Oil sump
6 Oil pump
7 Scoop tube
Type SVNL vert.
Dimensions available upon request
The motor bearing ring is specially fitted to the motor and to the flange of the driven machine.
Variable-Speed Turbo Coupling Type SVN
The variable-speed turbo coupling type SVN is of non-self-supporting design. This means the rotating parts of the coupling are supported proportionately by the motor shaft and the driven machine. This simplified construction allows for the shortest possible distance between the driving and driven shafts to be achieved. The fixed parts, including the scoop tube housing and the scoop tube are supported by the base via the oil tank.
An electrically driven oil pump maintains the oil flow through the coupling.
Simplified longitudinal section drawing
1 Primary wheel
2 Secondary wheel
3 Shell
4 Scoop tube housing
5 Oil sump
6 Oil pump
7 Scoop tube
Performance characteristics variable-speed turbo coupling type SVN, SVNK and SVNK vert.
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The variable-speed turbo coupling type 487 SVN with intermediate transmission driving a circulation pump.
Covers of the rotating parts are removed for demonstration.
Type SVN Dimensions in mm
Size A B C1 C2 Oil
require mentWeight 274 325 335 400 400 15 135 kg 316 325 335 400 400 15 150 kg 366 449 495 510 605 55 300 kg 422 467 495 510 605 55 330 kg 487 467 495 510 605 55 340 kg 562 570 615 730 640 95 510 kg 650 570 615 730 640 95 540 kg 750 740 760 800 800 240 1020 kg 866 771 760 800 800 240 1100 kg Dimensions subject to change without further notice.
Variable-Speed Turbo Coupling Type SVNRI, SVNK and SVNK vert.
The coupling types SVNRI, SVNK and SVNK vert. are partly non-self-supporting designs. That means, the weight of the rotating parts is supported by the shaft of the main motor on the pinion end; on the drive side, a bearing is built into the scoop tube housing.
The main motor is mounted together with the turbo coupling on the oil tank, resulting in a compact drive unit. The electrically pump for maintaining the oil flow through the coupling is mounted on the oil tank.
The coupling type SVNRI can be fitted with a pulley on the drive side. The SVNK type was developed for coaxial output and the type SVNK vert. for vertical use.
Simplified longitudinal section
1 Primary wheel
2 Secondary wheel
3 Shell
4 Scoop tube housing
5 Oil sump
6 Oil pump
7 Scoop tube
Performance characteristics variable-speed turbo coupling types SVNRI.
SVNK and SVNK vert. please refer to type SVN
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Variable-speed coupling type 650 SVNK with intermediate transmission driving a conveyor belt.
Type SVNRI Dimensions in mm
Size A B C Oil
requirementWeight 274 815 355 420 15 145 kg 316 815 355 420 15 145 kg 366 1205 535 730 80 465 kg 422 1205 535 730 80 495 kg 487 1205 535 730 80 505 kg 562 1685 658 950 100 910 kg
Type SVNK Dimensions in mm
Size A1 A2 B C Oil
requirementWeight 366 1205 548 535 730 80 465 kg 422 1205 548 535 730 80 495 kg 487 1205 548 535 730 80 505 kg 562 1685 640 535 730 100 910 kg 650 1685 640 535 730 100 940 kg 750 2650 953 770 1320 240 1445 kg 866 2650 953 770 1320 240 1525 kg Dimensions subject to change without further notice.
Type SVNK vert.
Dimensions available upon request.
Integration of the Variable-Speed Turbo Coupling into a Control Circuit
Variable-speed turbo couplings serve to control the speed (rev/mm) of machinery.
In many cases, the couplings are installed into an automatic process.
Position Control Circuit
Components:
- Position controller
- Actuator for continuous control
- Position feedback
Process Control Circuit
Components:
- Position controller
- Process controllerIf the speed is used as a process input, or if it is to be displayed, the following components are required:
- Pole wheel
- Pick-up
- Converter
- Indicator
As with the speed (rev/mm), a process value (e.g. pressure, flow rate, etc.) can be installed into a control circuit. Then the process input is used as the set value in place of the speed.
Torque Curves of Various Driven Machines in Relation to Variable-Speed Turbo Coupling Characteristics
Operating and Control Ranges
The operating ranges of the variable-speed turbo couplings can be seen on the diagram where the coupling torques (MK) which can be transmitted at varying scoop tube ratios as a function of the speed. ratio n1 : n2 are shown. The characteristics are divided into different range market I-IV.
Control range II is the main operating range of the variable-speed turbo coupling. In this range the various load characteristics have been entered. It includes the torque and speed range where high control precision can be achieved.
The desired output speed n2 is the stable intersection of coupling torque MK (coupling characteristics) and load torque (load characteristics).
The following two coupling characteristics limit the control range: the characteristics of the 100% scoop tube position reflect the maximum output speed attainable under load conditions and the so-called rated slip, Sn is maintained; the characteristics for 0% scoop tube position shows the required minimum load torque/ Mmin, for the desired speed range.
The required speed adjustment is achieved by changing the slip between the two impellers.
Operating Ranges
PIC I, IV Starting Range PIC II Control Range PIC III Overload Range The shape of the coupling characteristic curves is given for information only, since there may be minor deviations if coupling sizes, circulating oil flows, oil viscosity, etc. vary.
Parameters:
Scoop tube position in % of the full scoop-tube stroke.
Mmin : Minimum torque required for minimum speed adjustment. Smin : Minimum slip required for torque transmission Sn = Rated slip at design point S =
(1 - n2 ) x 100 [%] n1 n1 = input speed n2 = output speed Typical load characteristics:
1. rising torque (e.g. processing pumps for changes in viscosities or specific weight).
2. constant torque (e.g. conveyor belts, volumetric pumps with constant pressure.
3. decreasing torque (e.g. boiler feed pumps operating at varying pressures).
4. parabolic torque (e.g. resistance parabola, pumps without back pressure, blowers).
5. decreasing torque (e.g. boiler feed pumps operating at fixed pressure).The Benefits of Voith Variable-Speed Turbo Couplings
Easy to operate, low maintenance components for universal speed control and adjustment.
Wear-free power transmission is achieved by hydrodynamic energy.
Reduced wear on motor and drive units as a result of smooth machine acceleration, even with the heaviest masses.
Sturdy design, long life, high availability and low maintenance.
Compared to conventional throttle control involving parts subject to extreme wear, speed control provides higher efficiency when operating at partial load, as well as power savings.
Flawless operation in a variety of alternative control systems (electromechanical, pneumatic or hydraulic).
Realization of special requirements such as no-load and/or quick-start, starting torque, acceleration and/or deceleration limitation.
Separation of driving and driven machine during operation.
Damping of shock and vibrations.
Lubrication of connected equipment.
Standard oils may be used as working medium.
Efficiency can be increased by recirculating slip heat into the operating process.
Suitable for a great variety of environmental conditions (tropical or desert climates, low temperature areas; explosion-proof versions are also available).
Quick reaction times and high adjustment precision.
