Wet rotor pump motor stator sealing liner

0001This application relates to a sealing liner to be incorporated into a motor for a pump, wherein pump fluid cools the motor.

0002Pumps are typically driven by electric motors. In one known type of electric motor, pump fluid is allowed to flow across a motor rotor for cooling the motor rotor. The motor rotor is isolated from the motor stator by a sealing liner.

0003In known motors, a position sensor, which may be known as a resolver, is also incorporated to determine the current position of the motor rotor. This is required to provide feedback to a motor control of the position of the pump which is driven by the motor rotor.

0004<patcit id="pcit0001" dnum="US20030178903A"><text>US 2003/0178903</text></patcit> discloses a sealing liner of the type defined in the preamble of claim 1. The present invention is defined by the accompanying independent claims.

0005The invention provides a sealing liner for use in a pump motor, said sealing liner having a radially enlarged portion at one end, and a radially smaller portion extending from said one end to an axially opposed end, an axial length of the sealing liner including the radially smaller portion and the radially enlarged portion being defined as a first length, and an axial length of said radially enlarged portion being defined as a second length, wherein an inner diameter is defined at said radially smaller portion, wherein said sealing liner has an outer diameter throughout said first length which is generally constant from said one end to said axially opposed end, and said sealing liner is open at each of said one end and said axially opposed end; characterised in that the radially enlarged portion is for being received, when in use, in a space formed between an end shield and a casing of the pump motor; said inner diameter is 1.58 inches (4 cm), and said outer diameter is 1.64 inches (4.2 cm); and a ratio of said first length to said second length is between 6.5 and 8.5.

0006The present invention provides also a method of replacing a sealing liner in a motor for driving a pump comprising:inserting a sealing liner into the motor between a motor stator and a motor rotor, the sealing liner being dimensioned such that it extends radially inwardly of both the stator and a position sensor.

0007These and other features of the invention will be better understood from the following specification and drawings, the following of which is a brief description. <ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">Figure 1</figref> shows a motor structure including a sealing liner according to an exemplary embodiment of the invention.</li><li><figref idref="f0002">Figure 2</figref> shows the sealing liner as part of the embodiment.</li></ul>

0008<figref idref="f0001">Figure 1</figref> shows a pump assembly 20 having a pump unit 22 which is driven by a motor 24. The motor 24 incorporates a stator 28 driving a rotor 26 in a known manner. As shown schematically at P, pump fluid is allowed to flow across the rotor 26 for cooling. In fact, the actual flow of the pump fluid for cooling purposes may travel along the outside of the rotor 26 from the pump 22 into the motor 24, and then be discharged through the inside of the rotor 26, as generally shown by the arrows P.

0009A position sensor 32, which may be a resolver, sits adjacent the stator 28. A sensor portion 30 of a position sensor 32 rotates with the rotor 26. A chamber 35 receives the rotor 26 and also receives the pump fluid from the connection P. Sensor 32 senses the position of portion 30, and communicates with a control (not shown).

0010A sealing liner 34 is generally cylindrical in shape and incorporates a radially enlarged or thickened end 36, a rotor portion 38, and a sensing portion 40. The rotor portion 38 and the sensing portion 40 have generally the same diameter, and thus, the part may be extruded. The sealing liner 34 thus extends between the rotor 26 and stator 28, and between sensor 32 and sensor rotor portion 30. The sealing liner 34 extends between open axial ends.

0011<figref idref="f0002">Figure 2</figref> shows the sealing liner 34 having the radially enlarged portion 36 extending for a length L₂. The overall sealing liner 34, including the portions 36, 38, and 40 extends for a length L₁.

0012L₂. may be about .63" (about 1.6 cm) and L₁ was about 5.3" (about 13.4 cm) in one embodiment and about 4.1" (about 10.4 cm) in another. In embodiments, a ratio of L₁ to L₂. is between approximately 6.5 and approximately 8.5.

0013The inner periphery of the portions 38 and 40 is defined by a dimension d₁, and the outer periphery is defined by a dimension d₂. In the embodiment, d₁ is 1.58" (4 cm) and d₂ is 1.64" (4.2 cm). A ratio of d₁ to L₁ may be between approximately .4 and approximately .33.

0014The sealing liner 34 may be formed of carbon fiber filled polyetheretherketone (PEEK). However, other suitable materials may be used. Specific examples would include Victrex 450CA30™, or 30% carbon fiber filled PEEK.

0015Although embodiments of this invention have been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.