High efficiency hydronic circulator with sensors

Abstract

A highly efficient circulator system is provided, useful for hydronic systems, including both heating and cooling systems. The stand-alone circulator motor is controllable by input from certain sensors, preferably thermal sensors, which provide data enabling the controller of the brushless pump motor to vary its flow output to meet changes in systems loads. The circulator has a ceramic permanent magnet rotor, such as a ferrite, with an electronically, preferably sinusoidally, commutated, electro-magnetic stator controlling the input of electrical power.

Description

[0001]This application claims the benefit of priority pursuant to 35 U.S.C. 119(e) from a U.S. Provisional Patent Application No. 62 / 115,050 filed on Feb. 11, 2015, the text of which is fully incorporated by reference herein as if repeated below.[0002]The present invention is directed to a highly efficient circulator system, useful for hydronic systems, including both heating and cooling systems. Specifically, this stand-alone circulator is controllable by input from certain sensors, preferably thermal sensors, which provide data enabling the controller of the brushless pump motor to vary its flow output to meet changes in systems loads. The circulator has a molded, ceramic, such as a ferrite, permanent magnet rotor with an electronically, preferably sinusoidally commutated, electro-magnetic stator controlling the input of electrical power.BACKGROUND OF THE INVENTION[0003]It has previously been well known to provide a thermal sensor-controlled, electronically commutated, permanent m...

AI Technical Summary

Benefits of technology

[0013]The rotor and stator of the present invention are both elongated, to meet the spatial requirements of the somewhat larger ferrite magnet being used, and to be able to encompass the increased number of turns of wire forming the stator, to achieve the desired magnetic flux from the lower current flow to the motor from the high voltage power, and the weaker ferrite magnet forming the rotor.

[0014]For example, for a common small pump motor, a suitable rare earth motor rotor, with an internal backiron, would be about 0.5 in. long, but when using a common ferrite magnet rotor, the rotor must be elongated to about 1.4 ins. long, to achieve a similar power output. However, it is well-known in the art to manufacture an anisotropic ceramic ferrite magnet. When using an anisotropic ceramic ferrite magnet, the magnetic flux can be greatly increased (up to about 1.8 times that of a common ferrite magnet rotor), depending upon the method of manufacture. So that, for example, following the preceding examples, using an anisotropic ferrite magnet rotor 1.4 ins. in length, allows for greater output and efficiency, with lower noise, but is less costly than a rare earth magnet.

[0015]The electronic commutation for the permanent magnet rotor motor can be provided, by way of example only, by an operational amplifier (“OPAMP”) and a comparator, operating in combination with the OPAMP, along with a microprocessor. These electronic control elements are all mounted preferably in the motor case. This motor is further improved by using the sinusoidal wave function for motor control of this invention, which results in a far quieter and more effective control system, and greatly improves the efficiency of the controlled operation of the circulator. Electronic systems for providing sinusoidally varying direct current voltage are well known to the art and do not, themselves, form a part of this inventive combination described herein. The lower current flow reduces the heat generated in the motor, although the stator further includes a greater number of wiring turns to compensate for the lower current flow at the higher voltage, in order to obtain the necessary magnetic flux.

[0016]As a result of the reduction in the inductance created between the electrical coils and the ferrite permanent magnet which does not include a back iron, as is commonly used with rare earth magnets, and the ability to drive the system with greater force without fear of demagnetization of the ferrite permanent magnet, the system can be smoothly controlled, from a full stop to maximum flow, by providing for sinusoidal changes in the magnetic flux from the stator electromagnets created by the sinusoidally varying direct voltage.

[0017]Moreover, the flux from a standard ceramic ferrite magnet can be further increased by orienting the magnet so as to form an anisotropic ferrite magnet. It is also well-known that the flux can be increased further, again, without changing the ferrite material, by forming a Halbach array, anisotropic ferrite magnet. By increasing the flux, the number of wire turns in the stator need not be increased, or increased less, as compared with the use of rare earth permanent magnets. The advantages of the ferrite magnet regarding inertness to the wet environment and maintaining magnetic quality at higher temperatures, and the higher voltage and lower current flow, remain, in each of the above cases.

Problems solved by technology

The use of the rare earth rotor magnet and the use of relatively low input voltage of 12 volts DC, resulted in a motor which, although relatively highly efficient, was costly, utilized a trapezoidal control strategy, and resulted in a motor that was noisier than desirable for residential use.

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