Tech 101 how and why a fluid coupling works daniel strohl on jan 4th. This fluid coupling would capture the mechanical power from the main source, namely the i. The yotc series variable speed fluid couplings developed and made by our company belongs to the type which the couplings speed is regulated by adjusting the oil volume out from working chamber. The working principle of fluid can be easily explained by the taking two fans in which one is connected to the power supply and other is not. Dec 15, 2017 a fluid coupling or hydraulic coupling is a device used for transmitting power from one shaft to another shaft by means of acceleration and deceleration of a hydraulic fluid. Using the hydrodynamic principle, a fluid flow transmits the power from the pump wheel to the turbine wheel. Working operation extremely efficient perfomance is achieved operating the ksls very simple and effective principle. Dec 26, 2017 oil flow circuit diagram of variable speed fluid coupling or scoop coupling. The sliding scoop tube in this types of coupling governs the oil level in the working circuits depending on scoop tube position between 0% to 100%.
Variable speed drives in the hydraulic field are made up of fluid couplings which operate through the medium of oil, water, or silicone compounds. As shown in above figure, power can be also transmitted from a motor a driver to a driven machine without direct operating principle using a pump, a turbine and associated piping. Metal tube variable area flow meters measures volumetric flow rate of liquid and gases that operates on the float principle. It has been used in automobile transmissions as an alternative to a.
Variable speed fluid couplings driving centrifugal compressors and other centrifugal machinery 61 dampening of torque peaks and no harmonics from either side and thus, decreasing mechanical stress in the whole drive line disconnecting driven machine possible while driver keeps running. It takes place of mechanical clutch in an automatic transmission. Fluid coupling, the principles of operation, film 15. The rotameter is an industrial flowmeter used to measure the flowrate of liquids and gases. Mechanical and electrical technology iv variable speed fluid coupling is common used in speed fig. Fluid couplings have no diffuser vanes between the pump index p and turbine. Load sharing between the two motors has been achieved by appropriately adding fluid to one coupling or withdrawing fluid from the other coupling. Fluid coupling main parts, principle, working and application. Install sheave to fluid coupling hub, torque bushing capscrews. At the same time, the fluid coupling protects the drive system to the maximum degree, even under extreme operating conditions, against damage and this reduces downtimes. Mar 06, 2012 henfels hfpm variable speed hydrodynamic coupling was released in 2009. Transfluid coupling, fluid couplings, variable speed drives.
Jan 26, 2020 coupling voltage across the circuit is varied through the movable core, which in turn changes the flux and voltage across the secondary terminals. It consists of a pump generally known as impeller and a turbine generally known as rotor. Fluid coupling main parts, principle, working and application june 22, 2017 december 26, 2018 pankaj mishra 4 comments automobile fluid coupling is also known as hydraulic coupling is a hydrodynamic device which is used to transfer rotational power from one shaft to another by the use of transmission fluid. Yot series operation principle the yot series variable speed fluid couplings are operating in the following principle. However, any dirt in the system can cause wear of seals or obstruction of control valves, resulting in erratic operation or failure. Fluid couplings allow for no load startup of prime mover.
By controlling the oil flow to the working circuit through a frequency converter, changes occur inside the couplings working circuit which alter the couplings slip characteristics dramatically softening the start up. The toandfro movement of the coil inside the outer core generates variable coupling, and the output voltage decreases based on direction either negative or positive. Variable area flowmeters for fluid power applications. In drives consisting fluid couplings, there is no mechanical contact between the driver and the driven. Fluid couplings, variable speed drives, brakes, clutches, couplings and hydraulic transmissions constitute the core of the product line, while ultramodern technology, careful selection of materials and meticulous assembly are the key ingredients in the recipe that has placed those products at the forefront of the market. Hence a fluid coupling cannot achieve 100 percent power transmission efficiency.
I have noted wide application of fluid coupling in large conveyor belt drive system and also fluid couplings are using these days as one substitute of mechanical clutch in automobile transmission system. Nevertheless, for completeness, other types of variable speed drives for load equipment are briefly discussed. The principle the geared variable speed coupling combines a hydrodynamic variable speed coupling and a mechanical gearbox in one compact unit. Fluid coupling, boiler feed pump, high pressure pump, carbon dioxide emission reduction, rotating speed control. In almost all pumping applications, some means is required to provide variable flow andor variable pressure of a liquid as it leaves a pump and enters a process application.
The fluid coupling can work as a clutch in an automobile. It also has widespread application in marine and industrial machine drives, where variable speed operation andor controlled startup without shock loading of the power. It is used for transmitting power or torque from one shaft to other shaft with help of an oil fluid, without mechanical connection between the two shafts. Fluid coupling working principle advantages of fluid. It consist of two rotating elements as radial pump impeller and radial flow reaction. Transfluid coupling, fluid couplings, variable speed. It is commonly used to provide variable speed drives. Construction, working principle, characteristics and. The fluid coupling consists of a pump impeller on the input shaft and a runner on the output shaft. The contents of this post were originally published in the variable speed drive chapter of the international pump handbook. It is a situation when the turbine achieved approximately 90 percent speed of the impeller and this point is called coupling point. The maximum torque of the fluid coupling can also be set to a predetermined value by adjusting the oil level.
Design and mathematical modeling of fluid coupling for. The fluid flows up through the tapered tube forcing the float to a position with sufficient free area to enable the flow to pass. Fluid couplings fluid couplings or hydraulic couplings work on the hydrodynamic principle. Army felt it was necessary to train its mechanics in a fluid coupling s operating principles in 1953. Transfluid has designed their ksl series variable fill fluid coupling to overcome problems experienced at start up and speed variation operation for medium and high power machines, driven by electric motors and internal combustion engines. Elecon working principle of scoop controlled variable speed fluid coupling. Voith offers fluid couplings and solutions for highly efficient and reliable drive solutions for the mining.
Transfluid has always been a point of reference in the world of industrial transmission equipment and the rule by which its competitors measure themselves. Fluid coupling, the principles of operation, film15. Fluid coupling is based on hydrokinetic principles and requires that the output speed be less than the input. Fluid coupling working principle advantages of fluid coupling,types. A torque converter is a type of fluid coupling which is used to transfer rotating power from the engine of a vehicle to the transmission. Voith turbo provides fluid coupling and drive solutions for the. What is and how does a variable area flowmeter work. Fluid coupling working principle as the electric motor accelerates to the running speed, the impeller begins to centrifugally pump oil to the stationary runner. Fluid coupling is coupled between drive shaft and driven shaft. Fluid couplings have the same characteristics in both directions of rotation.
Variable speed hydraulic coupling and drive unit of hydraulic. Elecon working principle of scoop controlled variable speed. Overview of fluid couplings a fluid coupling is a rotating speed controller that is placed between the driver such as a motor and driven. Its interesting how that simple fluid coupling has evolved. They provide additional safety to drive motors and torque transmission control. The fluid in the coupling absorbs misalignment of both shafts. Elecon working principle of scoop controlled variable. Fottinger principle the fottinger coupling originally the operating principle of the fluid coupling is based on the hydrodynamic torque converter patented by hermann fottinger 1877 1945. Fluid coupling is a combination of pump and turbine acting and reacting simultaneously to give birth a new hybrid element for torque transmission. Fluid coupling is also known as hydraulic coupling and it is basically one hydro kinetic transmission device that will act as a centrifugal pump and hydraulic turbine.
His patents from 1905 covered both fluid couplings and torque converters a mr bauer of the vulcanwerke collaborated with english engineer harold sinclair of hydraulic coupling patents limited to adapt the fottinger coupling to vehicle transmission in an. Fluid coupling working principle mechanical engineering. This type of flowmeters consists of a float inside a conical tube. Input powers from 1 to 30 mw and output speeds of up to 20,000 rpm are possible. Hydrokinetic fluid couplings operate on the kinetic energy transfer principle while the silicone fluid coupling operates on the principle of shear. The float reaches a stable position when the upward force exerting by the flowing liquid equals the weight of the float. The turbine wheel is connected to the driven machine via the output shaft. This free area is related to the flow rate, the weight of the float and the density and viscosity of the fluid. Fluid coupling also used in heavy vehicle like trucks as a retarder unit. Torque converter working, principle, main parts and. Sizes 7 through are provided with an adapter collet. Working principle of variable speed fluid couplingguangdong zhongxing hydraulic transmission co. Fluid couplings or hydraulic couplings work on the hydrodynamic principle. Feb 15, 2015 working principle of a scoop coupling the oil flow gives up power as it return to the impeller again and thus the cycle is repeated the input side of the scoop coupling connected to the motor is known as the pump side and the output side connected to the load is known as the turbine side hence while running the power is transmitted from the.
Correct operation of a fluid coupling depends on it being correctly filled with fluid. The type tvv fluid coupling is comparable to the type tv fluid coupling. This article covers fluid coupling working principle,advantages. A fluid coupling or hydraulic coupling is a device used for transmitting power from one shaft to another shaft by means of acceleration and deceleration of a hydraulic fluid.
Working principle of a scoop coupling mathematically slip s. The psc fluid coupling provides stepless variable output speed, using a fixed speed motor, over a range of 5. Torque converters, dual stage torque converters, lockup torque converters, even variable rate torque converters. This is a great advantage, allowing smaller motors or engines to be used and offers great savings on both setup and running costs. The hydrodynamic principle of a fluid coupling makes it possible to gently accelerate driven machines and to transfer power in a wearfree manner. As we everybody aware that pump is transforming kinetic energy of impeller into pressure head in fluid and turbine in turn absorb the pressure head and produce kinetic energy of runner. Compared with turbine flow meters, which are normally selected for highaccuracy applications such as hydraulic fluid characteristic measurement on tes t stands and feedback for a hydraulic system control, variable area flowmeters meet a diverse range of fluid power requirements. The geared variable speed coupling controls the speed of the driven machine precisely, quickly and repeatably.
That was a nice article on fluid coupling and the writer has comprehensively explained the structural components of the coupling and explains its function in details. Construction, working, operation and maintenance of fluid. That same film was shown in one of my technical training classes in college. They are equipped with filters and other measures to preserve the cleanliness of the working fluid. The oil to the coupling is supplied by the working oil pump, which is interlocked with the drive shaft. The parabolic operation of the variable speed fluid coupling matches that of the centrifugal pump or fan, making the vsds a preferred method. Thousands of variable speed fluid couplings in pump and. A fluid coupling cannot develop output torque when the input and output angular velocities are identical. Fnct fill control coupling fluidomat fnct fnct fluid couplings working on principle of hydro dynamic power transmission with fill control are ideal as start up and accelration control equpments for large drive motors. Working operation extremely efficient performance is achieved utilizing the ksls very simple and effective principle. Above figure shows schematic view of a scoop tube type variablespeed fluid. Its operation is based on the variable area principle. The voith turbo fluid coupling type t basic design, shown in above figure, consists of a few main components without additional adjoining storage chambers.
It features a tapered metal tube, in which a float is allowed to move freely up and down. I will be visiting this site occasionally to read more mechanical engineering articles. The hydrodynamic principle of power transmission was. Type hln fluidomat offers drain type fluid couplings hlnlc for combustion engine3 drive. Henfels hfpm variable speed hydrodynamic coupling animation. Fluid couplings have no diffuser vanes between the pump index p and. Transmission of oil is diffused by the conical impeller baffle, producing a gradual increase in torque, allowing the motor to accelerate rapidly to full running speed. We played with tops in childhood, rope was wounded around top and left on floor it rotated. The driven machine starts up more gently, and the torque limitation behavior is significantly stronger during the startup. Fluid couplings have become a science unto their own.
Coupling voltage across the circuit is varied through the movable core, which in turn changes the flux and voltage across the secondary terminals. May 22, 2018 fluid coupling is coupled between drive shaft and driven shaft. Fluidomat sc is a variable speed fluid coupling providing stepless speed variation in a wide range when connected to fixed speed electric motor. Hydrodynamic coupling turbo coupling, flow coupling, fluid coupling hydrodynamic brake retarder, flow brake in honor of hermann fottinger as their inventor, hydrodynamic power transmitters are also referred to as fottinger units. A fluid coupling is a hydrodynamic device used to transmit rotating mechanical power. The integrated oil system fills the hydrodynamic variable speed coupling with the working oil. Operating principle the hydraulic coupling is equivalent to a combination of centrifugal pump and hydraulic turbine, the hermetic working chamber formed. Peikert regional manager voith transmissions, incorporated houston, texas gunther h.
Mar 12, 2014 elecon working principle of scoop controlled variable speed fluid coupling. Variable speed fluid couplings introduction guangzhou. Ksl variable fill fluid couplings transfluid pdf catalogs. Oil flow circuit diagram of variable speed fluid coupling or scoop coupling.
Due to slippage that will occur in any fluid coupling under load, some power will always be lost in fluid friction and turbulence, and dissipated as heat. By controlling the couplings feed pump oil flow to the working circuit by a small a. Variable speed hydraulic coupling and drive unit of. Variable area flowmeters for fluid power applications flow. Variable speed fluid couplings driving centrifugal compressors and other centrifugal machinery by gunther h. Layout of variable speed fluid coupling and its working principle is shown in fig. Working principle of variable speed fluid coupling.
These coupling have a sliding scoop tube which enters the coupling rotating casing. Jun 22, 2017 fluid coupling main parts, principle, working and application june 22, 2017 december 26, 2018 pankaj mishra 4 comments automobile fluid coupling is also known as hydraulic coupling is a hydrodynamic device which is used to transfer rotational power from one shaft to another by the use of transmission fluid. Two alternative approaches exist, either a a variable speed. The integrated oil system fills the hydrodynamic variable speed coupling with. Oil, as the power medium, is pumped from a sump to the hydrodynamic coupling circuit, where it is finally drainedoff through a series of orifice plugs, back into the sump. Reliable speed control geared variable speed couplings. As an added benefit, motors on multiple drive systems can be individually started because of the ability of one coupling to temporarily operate at 100% slip. The mass forces are transmitted via a flowing fluid e. Feb 04, 2010 the primary emphasis of this post is to focus on variable speed fluid drives for pumps such as boiler feed pumps, condensate pumps, and pumps for other fluids and applications. Construction, working, operation and maintenance of fluid couplings. Flender fludex couplings from siemens are hydrodynamic fluid couplings operating according to the fottinger principle. About us xinxiang jintian hydraulic transmission co. The torque converter is the basic unit, with the coupling and brake being special cases. Having all the same advantages of fluid couplings, variable fill.
Variable torque trouble free performance this variable fill coupling is party supported from the bed plate by a stationary bracket. A fluid coupling or hydraulic coupling is a hydrodynamic or hydrokinetic device used to. It has been used in automobile transmissions as an alternative to a mechanical clutch. When starting up, there is much less operating fluid in the working circuit. Using the hydrodynamic principle, a fluid flow transmits.