Patents Assigned to Danfoss
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Patent number: 4315598Abstract: The invention relates to a heat emitter unit for a hot water heating system. The heat emitter unit is characterized by a valve and a heat emitter unit being integrated in a manner so that the valve casing and the heat emitter pipe to which fins are attached are in axial alignment. The heat emitter pipe has a central tube arrangement which provides in parallel a central bypass and a surrounding valve controlled passage. Heat from hot water flowing through the surrounding valve controlled passage is transferred through the finned pipe to the fins.Type: GrantFiled: July 31, 1980Date of Patent: February 16, 1982Assignee: Danfoss A/SInventor: Stephen M. Madigan
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Patent number: 4297845Abstract: The invention relates to a hydrostatic control unit of the metering type utilized for some automotive type power steering systems. The control unit has a valving section with inlet and outlet ports connectable to a pump and a tank and two working ports connectable to opposite sides of a bidirectional servomotor which is connectable to wheel steering linkage. A metering motor controlled by the valving section supplies and exhausts metered fluid to and from the servomotor through the two working ports of the valving section. The valving section has a single movable slide element cooperable with a stationary housing member. A gearing unit which may be of the planetary type is provided having two inputs and one output with the two inputs being connectable to the vehicle steering wheel and the metering motor input shaft and the output being connectable to the slide valve element.Type: GrantFiled: November 26, 1979Date of Patent: November 3, 1981Assignee: Danfoss A/SInventor: Erik Kyster
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Patent number: 4297608Abstract: The invention relates to a measuring probe for the acoustic determination of the specific gravity of a liquid. The probe includes a holder to which is attached at opposite ends thereof a ceramic piezoelectric transducer disc and a reflector disk. A reference element having a known acoustical impedance has one end thereof abutting the transducer disc and the other end thereof spaced from the reflector disc to form a sampling space therebetween.Type: GrantFiled: May 1, 1980Date of Patent: October 27, 1981Assignee: Danfoss A/SInventor: Borge R. Jensen
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Patent number: 4291544Abstract: The invention relates to control apparatus for feeding liquified refrigerant to the evaporator of a refrigeration system. A main valve controlled by a differential pressure type servo-element controls the flow of refrigerant to the evaporator. A float type pilot valve has a nozzle and closure member controlled by a float which has a liquid level identical to liquid level in the evaporator. A pilot conduit which extends between the main valve and the pilot valve has first and second throttle units arranged in series. The first throttle unit controls a flow of liquid refrigerant through the pilot conduit to control the main valve. The second throttle unit controls a flow of refrigerant through the pilot conduit which is at least partially in vapor form. This arrangement with two throttle units allows control over a broader proportional range for the settings of the float in the pilot valve.Type: GrantFiled: March 31, 1980Date of Patent: September 29, 1981Assignee: Danfoss A/SInventor: Kurt A. Larsen
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Patent number: 4290553Abstract: The invention relates to a manually setable, knob-type thermostatic control assembly for radiator valves. The knob normally has a fixed or usual setting to provide a desired temperature for a room. Occasionally the setting is temporarily changed for one reason or another and the unit must be reset to its usual setting. This is facilitated herein and in the prior art by providing index markings on the relatively rotatable members. The novelty herein, however, is in providing a cap for the rotatable knob member which carries the index marking and the cap is readily adjustable relative to rotatable member in a simple manner without detaching the cap from the knob member.Type: GrantFiled: May 13, 1980Date of Patent: September 22, 1981Assignee: Danfoss A/SInventors: Aage Molgaard, Niels P. G. Graversen
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Patent number: 4283646Abstract: The invention relates to a brushless type electric motor having an axial air gap and is directed to a particular design and arrangement for the pole shoes thereto.Type: GrantFiled: March 17, 1980Date of Patent: August 11, 1981Assignee: Danfoss A/SInventors: Poul E. Hansen, Jan Dyhr
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Patent number: 4275996Abstract: The invention relates to a control unit for an adjustable fluid pump or motor controlled by a servomotor. The control unit is of the type having a slide valve with a neutral blocking position with supply and exhaust positions on opposite sides of the neutral position. The neutral position provides a zero pump feed condition and the improvement resides in a construction wherein the fed amount is absolutely zero. This is accomplished with a secondary valve which has a fixed part and a moveable part which moves with the actuator. The secondary valve has fluid passages which short circuit the supply and exhaust connections of the unit over a small travel range on opposite sides of the neutral position of the actuator.Type: GrantFiled: June 13, 1979Date of Patent: June 30, 1981Assignee: Danfoss A/SInventors: Jan Zangenberg, Peter J. M. Clausen
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Patent number: 4272714Abstract: The invention relates to a starter device for single phase, asynchronous motors, the starter device being of the type which provides a PTC resistor for series starting operation with the auxiliary winding. The starter device may be used for different types of motors by reason of an arrangement of contacts for connecting the main and auxiliary windings, starting capacitors and a two phase power supply which accommodates different modes of starting operation required by different motors.Three capacitor contacts provide for connecting capacitors in different ways relative to the PTC resistor and one of two sets of winding contacts may be selected to suit a desired mode of starting operation.Type: GrantFiled: May 14, 1979Date of Patent: June 9, 1981Assignee: Danfoss A/SInventor: Holger V. Vind
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Patent number: 4270076Abstract: The invention relates to a brushless type DC motor assembly of the type having a permanent magnet rotor and a pair of poles provided with two windings, the windings having a common junction which is connectable to the positive terminal of a DC voltage source. A pair of controlled rectifiers in respective series with the windings are followed by a series branch having a smoothing choke and an electronic chopper switch, the series branch being connectable to the negative terminal of the DC voltage source. The invention is directed to an improved circuit permitting operation of the motor at higher power by providing an extinguishing circuit for the controlled rectifiers which includes a series arranged extinguishing capacitor and a swingover choke that connects the upstream sides of the controlled rectifiers. The extinguishing circuit also includes extinguishing diodes connected in antiparallel respectively to the rectifiers.Type: GrantFiled: August 29, 1979Date of Patent: May 26, 1981Assignee: Danfoss A/SInventor: Nils H. Nygaard
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Patent number: 4270075Abstract: The invention relates to a motor of the type energizable by a DC voltage and having at least two parallel stator winding branches with each branch having a stator winding in series with a controllable switching element. A demagnetization branch in parallel with each stator winding branch has an oppositely poled demagnetization winding inductively coupled to the associated stator winding and a series connected diode poled oppositely of the associated switching element. When one stator winding is switched off the voltage induced in the inductively coupled demagnetization winding produces a current which flows through the associated diode and the next simultaneously switched on stator winding. In this way the magnetic energy of the switched off stator winding is rapidly reduced and is utilized to supplement the magnetic field of the simultaneously switched on stator winding.Type: GrantFiled: June 28, 1979Date of Patent: May 26, 1981Assignee: Danfoss A/SInventor: Nils H. Nygaard
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Patent number: 4266464Abstract: The invention relates to hydraulic control apparatus for a servomotor of the type utilized for vehicle steering systems. Such apparatus has a control circuit controlled by a manually operated device such as a steering wheel and a power circuit connected between the servomotor and a power source such as a hydraulic pump. The power circuit includes resetting apparatus for throttling the return flow branch in a manner so that forces applied to the servomotor in the same direction as actuation are absorbed with a minimum of reactionary movement by the valves on the return flow side of the apparatus.Type: GrantFiled: June 5, 1978Date of Patent: May 12, 1981Assignee: Danfoss A/SInventors: Johannes V. Baatrup, Thorkild Christensen, Tage Christiansen, Svend E. Thomsen
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Patent number: 4261250Abstract: The invention relates to the slide shoe arrangement of a radial piston type of machine. This type of machine has a housing with a rotatable shaft and a piston carrier mounted on the shaft. Pistons in the carrier have reciprocal and radial movement relative to the carrier and shoes attached to the pistons have sliding engagement with an annularly shaped, eccentrically adjustable, track which surrounds the carrier. The track has a spherical surface portion with a predetermined radius R1. The shoes have spherically shaped surface portions of radius R2 which engage the track, radii R2 being larger than radius R 2 to form tapered gap chambers between the spherical shoe surfaces and the spherical track surface. The shoe portions may have annularly shaped flanges contacting the track surface through the spherical shoe surfaces. The flanges are resiliently connected to the shoe portions.Type: GrantFiled: May 18, 1979Date of Patent: April 14, 1981Assignee: Danfoss A/SInventor: Carl V. Ohrberg
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Patent number: 4259621Abstract: A speed regulator for a guide and follower motor assembly. A guide pulse frequency generator driven by a guide motor drives a frequency converter which drives a follower motor. The frequency converter includes a frequency regulator with a negative feed back which includes a frequency divider. Adjusting and setting circuits for the frequency divider include an up/down counter for operating the frequency divider, a resetting operation of the counter to provide a frequency indicating value for its output, an adjustable pulse generator for driving the counter, an add/subtract circuit, and a comparator responsive to the add/subtract circuit and the counter to control the pulse generator.Type: GrantFiled: August 31, 1978Date of Patent: March 31, 1981Assignee: Danfoss A/SInventors: Jakob S. Jakobsen, Robert M. McCulloch
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Patent number: 4259038Abstract: The invention relates to a pumping system for supplying fluid at a variable delivery rate in accordance with demand. The system includes one pump having a variable delivery rate and one or more auxiliary pumps arranged in parallel therewith, each having a fixed delivery rate. The variable delivery pump operates over a predetermined control range between minimum and maximum rates. Each fixed delivery rate pump has on and off operating modes with the on mode delivery rate being at the maximum delivery rate of the variable delivery pump. A control unit for operating the pumps matches the pump delivery with the demand. The control unit functions to set the variable delivery pump at its minimum delivery rate when operation of the fixed delivery pump is initiated during upward demand control and for setting it at its maximum delivery rate when operation of the fixed delivery pump is terminated during downward demand control.Type: GrantFiled: December 15, 1978Date of Patent: March 31, 1981Assignee: Danfoss A/SInventors: Iver Jorgensen, Steen Veigert, Niels E. Andersen
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Patent number: 4258899Abstract: The invention relates to a valve assembly. A closure member for the valve unit is controlled directly or indirectly by a movable wall of an expansible chamber filled with a refrigerant medium having vapor and liquid phases. The pressure exerted by the vapor phase of the medium provides a bias which is directly related to the temperature of the liquid phase. A heat transfer element such as a heating resistor in the liquid phase is heated or allowed to cool in a controlled manner by an external control unit. A temperature responsive sensor element in the liquid phase of the medium is part of a feedback system for the control unit which allows a selected temperature to be maintained in the chamber which results in a desired constant pressure to be maintained in the chamber. A pilot valve unit is disposed between the valve closure member and the movable wall. An expansible chamber behind the closure member houses a spring for biasing in a valve closing direction.Type: GrantFiled: November 1, 1978Date of Patent: March 31, 1981Assignee: Danfoss A/SInventors: Zbigniew R. Huelle, Leif Nielsen
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Patent number: 4257909Abstract: The invention relates to a cleaning fluid essentially consisting of aliphatic or saturated liquid hydrocarbons and an ethoxylate. The cleaning fluid is a three-phase system consisting of a liquid hydrocarbon which is poor in aromatic content, a wetting agent such as alkyl aryl ethoxylate or alkyl ethoxylate as the second phase, and between the two phases, which are inter-indissoluble, a linking agent consisting of diesterfield monoglycerides of fatty saturated or unsaturated acids. The result is a well-wetting fluid which is poor in aromatic content and does not have an offensive odor but does have a good linking of the hydrocarbon by means of a linking agent which does not cause any inconvenience in the form of skin injuries, eczema or the like.Type: GrantFiled: December 28, 1979Date of Patent: March 24, 1981Assignee: Danfoss A/SInventor: Erik F. S. Christianson
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Patent number: 4251793Abstract: The invention relates to a resistor of the type having a resistance which varies with temperature such as PTC and NTC resistors. The resistor is characterized by having three or more connector pads and several different arrangements for the connector pads.Type: GrantFiled: May 9, 1979Date of Patent: February 17, 1981Assignee: Danfoss A/SInventor: Holger V. Vind
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Patent number: 4251776Abstract: The invention relates to an analog computing device for converting a signal x to a different power with a selectable exponent. First and second RC type time dependent transfer elements, having the functions f.sub.1 and f.sub.2 =f.sub.1.sup.b are driven by a square wave generator. The output of the first transfer element is connected to the first input of a comparator and the second input of the comparator is supplied with the signal x of which the power is to be raised to the exponent b. An instantaneous value of the output signal of the second transfer element is scanned and held by a scanning and holding latch which is triggered by the output signal of the comparator which occurs when the signal x and the output signal of the first transfer element are equal.Type: GrantFiled: February 15, 1979Date of Patent: February 17, 1981Assignee: Danfoss A/SInventor: Henning M. Hansen
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Patent number: 4251758Abstract: The invention relates to a self-starting electric motor assembly of the type having a permanent magnet rotor, a stator with two windings and electronic switching elements for the windings controlled by switching signals occurring in push-pull and derived from control signals of a sensor detecting the angular position of the rotor. At standstill and for normal running operation the magnetic field distributions between the stator and rotor are selected in a known manner, so that the rotor assumes an angular position which is displaced in relation to the neutral position as an aid to starting and so that the switchover occurs at an angular position ahead of the neutral position to provide greater efficiency for the running operation.Type: GrantFiled: February 15, 1979Date of Patent: February 17, 1981Assignee: Danfoss A/SInventors: Hans-Kristian Pedersen, Frode Sorensen, Jorgen Hyldal
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Patent number: 4248377Abstract: The invention relates to a controlled heating system for maintaining a predetermined or set temperature in a medium of small dimensions which may be a gas, liquid or solid. A single element such as a power transistor functions as a heat transfer device for supplying heat to the medium and as a heat sensing device for sensing temperature changes in the medium which can be fed back and serve as control data for supplying make-up heat to maintain a predetermined temperature. The transistor supplies heat via heat dissipation in its collector-emitter path and senses heat changes via its base-emitter voltage which varies in response to temperature changes in the medium. The controlled heating may be applied to a valve assembly for a refrigeration plant of the kind used for controlling the flow of refrigerant from the evaporator to the compressor.Type: GrantFiled: November 1, 1978Date of Patent: February 3, 1981Assignee: Danfoss A/SInventor: Jakob S. Jakobsen