NON-INTRUSIVE VAPOR DETECTOR FOR MAGNETIC DRIVE PUMP

DETECTEUR DE VAPEURS NON INTRUSIF POUR POMPE MAGNETIQUE

English Abstract

A magnetic drive pump includes a magnetic coupling comprising an outer magnet rotor and an inner magnet rotor. The outer magnet rotor is driven by a separate motor. The outer magnet rotor is positioned radially outward of a sealing wall. The inner magnet rotor is positioned radially within the sealing wall, such that rotation of the inner magnet rotor causes the pump rotor to in turn rotate. The pump rotor drives a centrifugal pump impeller to move a liquid. A bubble detector is positioned outward of the wall such that it is in a dry side of the pump. The bubble detector sends a signal into a wet side of the pump to identify the existence of a gas within a pump fluid.

French Abstract

Une pompe à entraînement magnétique comprend un dispositif d'accouplement magnétique comprenant un rotor magnétique externe et un rotor magnétique interne. Le rotor magnétique externe est entraîné par un moteur séparé. Le rotor magnétique externe est positionné radialement vers d'extérieur d'une paroi d'étanchéité. Le rotor magnétique interne est positionné radialement à l'intérieur de la paroi étanche de sorte que la rotation du rotor magnétique interne entraîne la rotation du rotor de pompe. Le rotor de pompe entraîne une tête de pompe de pompe centrifuge à déplacer le liquide. Un détecteur de bulle est positionné vers l'extérieur de la paroi de sorte à être du côté sec de la pompe. Le détecteur de bulle envoie un signal sur un côté humide de la pompe pour signaler la présence d'un gaz dans le fluide de la pompe.

Claims

CLAIMS
1. A magnetic drive pump comprising:
a motor driving a magnetic coupling via a shaft;
said shaft driving an outer magnet rotor, said outer magnet rotor being
positioned radially outward of a sealing wall;
an inner magnet rotor positioned radially within said sealing wall, and such
that rotation of said inner magnet rotor causes a centrifugal pump impeller to
move a liquid;
and
a bubble detector positioned outward of said sealing wall such that it is in a
dry
side of said pump, said bubble detector sending a signal into a wet side of
said pump to
identify the existence of a gas within the liquid, wherein said signal is
received by said bubble
detector after having been set against an opposed suface, and being
transmitted back to said
bubble detector through said sealing wall.
2. The pump as set forth in claim 1, wherein said bubble detector is an
ultrasonic
detector.
3. The pump as set forth in claim 1, wherein said bubble detector
communicates
with a control.
4. The pump as set forth in claim 1, wherein said bubble detector is
positioned
adjacent to a portion of the wet side of said pump which is spaced from said
centrifugal pump
impeller.
5. The pump as set forth in claim 4, wherein a housing separates said
centrifugal
pump impeller from said portion of said wet side that is associated with said
bubble detector.
6. The pump as set forth in claim 1, wherein said bubble detector is a
single unit
having transmitting and receiving capabilities.

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Description

CA 02706266 2010-06-03
NON-INTRUSIVE VAPOR DETECTOR FOR MAGNETIC DRIVE PUMP
BACKGROUND OF THE INVENTION
This application relates to the use of a vapor detector for detecting gas in a
liquid flow in a magnetic drive pump.
Magnetic drive pumps are known, and typically include a magnetic coupling
that drives a centrifugal pump impeller. A motor drive is connected to the
outer
magnetic rotor of the magnetic coupling. The inner magnetic rotor of the
magnetic
coupling is connected to the pump impeller. A sealing wall is positioned
between
the outer magnetic and inner magnetic rotors, and provides a complete fluid
seal,
ensuring that the outer magnetic rotor is maintained in a "dry" side. Liquid
circulates within a "wet" side in the interior of the wall. The centrifugal
pump
impeller moves liquid from an inlet to an outlet.
Prior art has comprised a bubble detector for detecting bubbles, or other gas
within the liquid that has been positioned in the wet side of the pump.
SUMMARY OF THE INVENTION
A magnetic drive pump includes a magnetic coupling that drives a
centrifugal pump. A motor drives the outer magnetic rotor of the magnetic
coupling.
The outer magnetic rotor is positioned radially outward of a sealing wall. The
inner
magnetic rotor is positioned radially within the sealing wall. Rotation of the
outer
magnetic rotor causes the inner magnet rotor to rotate. The inner magnet rotor

drives a centrifugal pump impeller to move a liquid. A bubble detector is
positioned
outward of the wall such that it is in a dry side of the pump. The bubble
detector
sends a signal into the wet side of the pump to identify the existence of a
gas within
a pump liquid.
These and other features of the present invention can be best understood
from the following specification and drawings, the following of which is a
brief
description.
1

CA 02706266 2012-06-27
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a cross-sectional view through the inventive pump.
Figure 2 is a detail of the mounting of a bubble detector probe.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A magnetic drive pump is illustrated in Figure 1 having a sealing wall 22
separating a dry side 23 from a wet side 40 for a fluid pump. A separate motor

drives a shaft 28, through a bearing housing 24. Shaft 28 drives an outer
magnet
rotor 30, which is positioned outward of the wall 22. Magnetic flux passes
through
the wall 22 and drives an inner magnet rotor 32. A centrifugal pump impeller
34 is
connected to the inner magnet rotor 32. Fluid passes from an inlet 35 to the
impeller
34, and is driven to an outlet 37.
A bubble detector probe 36 is positioned outward of the wall 22 and
communicates with a control 38. The probe may be an ultrasonic probe that will
transmit and receive an ultrasonic signal. The signal transmission through
liquid, is
different to the signal transmission through gas. Therefore, the probe can
determine
whether the fluid inside the wet chamber is liquid, gas or a mixture of liquid
and gas.
The magnetic drive pump includes a "wet" side 40, which receives some of
the liquid being pumped by the impeller 34, such that the liquid can circulate
around
the components radially within the sealing wall 22. In addition, a "dry" side
23 is
positioned radially outward of the wall and does not receive the liquid. Probe
36 is
positioned in the dry side 23.
As can be appreciated, the probe 36 faces a portion of the wet side 40 spaced
away from the impeller 34. This positioning aligns the probe 36 with a portion
of
the chamber that is separated from the impeller by a housing wall 100.
As can be appreciated from Figure 2, and with reference to Figure 1, the
probe 36 is positioned to be opposite a bushing holder 102. An outer housing
wall
101 receives an olive/nut arrangement 110 to clamp and hold the probe into the

housing.
The sealing wall 22 is formed of non-magnetic material. The technology for
forming an appropriate ultrasonic transmitter to send a signal through the
wall 22,
and against the opposed surface, is known. Essentially, the controller 38 will
be able
2

CA 02706266 2010-06-03
,
to determine if bubbles of vapor or gas are within the pump fluid by analyzing
the
returned signal. While the technology for providing such a probe is known,
such a
probe has not been utilized in this non-invasive manner.
Although an embodiment of this invention has 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.
3

Representative Drawing