EP0688599A1 - A cooling device for mixers - Google Patents

A cooling device for mixers Download PDF

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Publication number
EP0688599A1
EP0688599A1 EP95850101A EP95850101A EP0688599A1 EP 0688599 A1 EP0688599 A1 EP 0688599A1 EP 95850101 A EP95850101 A EP 95850101A EP 95850101 A EP95850101 A EP 95850101A EP 0688599 A1 EP0688599 A1 EP 0688599A1
Authority
EP
European Patent Office
Prior art keywords
propeller
cooling device
electric motor
flow
motor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP95850101A
Other languages
German (de)
French (fr)
Other versions
EP0688599B1 (en
Inventor
Hjalmar Fries
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xylem Water Solutions AB
Original Assignee
ITT Flygt AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ITT Flygt AB filed Critical ITT Flygt AB
Publication of EP0688599A1 publication Critical patent/EP0688599A1/en
Application granted granted Critical
Publication of EP0688599B1 publication Critical patent/EP0688599B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
    • B01F27/25—Mixers with both stirrer and drive unit submerged in the material being mixed

Definitions

  • the invention concerns a cooling device for a mixer for operation in viscous liquids where amounts of solid bodies are frequent.
  • Mixers of this type comprise a driving unit such as an electric motor, a propeller and a driving shaft there between.
  • the propeller may be designed with two or more vanes and to be driven with various speeds depending on type of use.
  • Mixers are used within different fields for homogenizing and to keep particles in suspension in liquids for different industrial processes, in farming, for treatment of sewage water etc.
  • the mixer may be arranged horizontally or vertically or in different angle positions there between. It can also be arranged to move in such a way that the flow from the mixer is caused to sweep over larger areas or being directed towards certain spots within the liquid tank.
  • a jet ring is often arranged around the propeller having a diameter somewhat exceeding that of the propeller and a normally relatively limited axial extension. With no jet ring present a dominating radial flow is obtained which means that the axial flow through the machine becomes very limited as the same amount of liquid is rapidly sucked back to the propeller. In addition there is a leakage between the pressure and the suction side of the propeller which further decreases the axial flow.
  • the jet ring is normally designed as a cylinder having a somewhat expanding collar at its inlet to facilitate the inflow. Such jet rings are shown in the Swedish Design Registrations No:s 34601 and 39392.
  • the electric motor is cooled by the surrounding medium which calls for a certain flow around the motor, which flow normally is obtained by the mixer itself.
  • a certain flow around the motor which flow normally is obtained by the mixer itself.
  • the invention concerns a device for solving the problem mentioned above.
  • the invention is described more clearly below with reference to the enclosed drawings.
  • Fig 1 shows a mixer provided with a cooling device according to the invention
  • Figs 2 and 3 show flows around a mixer not provided with a cooling device, Fig 2, and with a cooling device, Fig 3.
  • the mixer here creates a flow symbolized by the arrows in the light part of the drawing.
  • the area close to the electric motor is not included in the flow which means an insufficient heat exchange between the motor housing and the surroundings.
  • Fig 3 is shown the flow increase or the extension of the area where flow takes place, which is obtained by help of the invention.
  • the propeller creates an under pressure at its inlet side, inside of the jet ring, which means that critical shear stress is exceeded and a flow is obtained through the jet ring along the wall of the motor housing which thus is given an effective cooling.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mixers Of The Rotary Stirring Type (AREA)
  • Accessories For Mixers (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

The invention concerns a cooling device for the electric motor in a submersible mixer. In order to increase the media exchange at the mantle surface of said motor (2) , the jet ring (4, 5) surrounding the propeller (3) is extended in such a way that the flow created by the propeller is partly forced to pass through the slot between the motor (2) and the ring (5).

Description

  • The invention concerns a cooling device for a mixer for operation in viscous liquids where amounts of solid bodies are frequent.
  • Mixers of this type comprise a driving unit such as an electric motor, a propeller and a driving shaft there between. The propeller may be designed with two or more vanes and to be driven with various speeds depending on type of use.
  • Mixers are used within different fields for homogenizing and to keep particles in suspension in liquids for different industrial processes, in farming, for treatment of sewage water etc. The mixer may be arranged horizontally or vertically or in different angle positions there between. It can also be arranged to move in such a way that the flow from the mixer is caused to sweep over larger areas or being directed towards certain spots within the liquid tank.
  • In order to obtain an effective mixing or flow a jet ring is often arranged around the propeller having a diameter somewhat exceeding that of the propeller and a normally relatively limited axial extension. With no jet ring present a dominating radial flow is obtained which means that the axial flow through the machine becomes very limited as the same amount of liquid is rapidly sucked back to the propeller. In addition there is a leakage between the pressure and the suction side of the propeller which further decreases the axial flow. According to known practice the jet ring is normally designed as a cylinder having a somewhat expanding collar at its inlet to facilitate the inflow. Such jet rings are shown in the Swedish Design Registrations No:s 34601 and 39392.
  • The electric motor is cooled by the surrounding medium which calls for a certain flow around the motor, which flow normally is obtained by the mixer itself. When mixing liquids that demand a certain shear stress to be exceeded before any movement is created, Bingham liquids, problems may occur to obtain a flow strong enough. This might cause the motor to be overheated.
  • The invention concerns a device for solving the problem mentioned above. The invention is described more clearly below with reference to the enclosed drawings.
  • Fig 1 shows a mixer provided with a cooling device according to the invention, while Figs 2 and 3 show flows around a mixer not provided with a cooling device, Fig 2, and with a cooling device, Fig 3.
  • In the drawings 1 stand for a mixer with a driving unit, electric motor 2 and a propeller 3. 4 stands for a jet ring and 5 an extension of this.
  • With reference to Fig 2 the conditions when mixing Bingham liquids are discussed. The mixer here creates a flow symbolized by the arrows in the light part of the drawing. The area close to the electric motor is not included in the flow which means an insufficient heat exchange between the motor housing and the surroundings.
  • In Fig 3 is shown the flow increase or the extension of the area where flow takes place, which is obtained by help of the invention. The propeller creates an under pressure at its inlet side, inside of the jet ring, which means that critical shear stress is exceeded and a flow is obtained through the jet ring along the wall of the motor housing which thus is given an effective cooling.
  • In the example above an extended jet ring has been used to obtain an effective cooling of the motor housing. It is however possible, according to the inventor, to arrange one or several means around the motor, parted from the jet ring, which obtain the necessary flow.

Claims (2)

1 A cooling device for mixers comprising an electric motor and a propeller with a driving shaft there between, said mixer, including the electric motor, being meant to operate submersed in the mixed medium, characterized in that the mantel surface of the electric motor (2) is partly or entirely surrounded by a cylindrical wall (5) for intensifying the media exchange at said surface.
2 A cooling device according to claim 1, characterized in that the wall (5) is an extended part of a jet ring (4, 5) surrounding the propeller.
EP95850101A 1994-06-22 1995-06-07 Mixer with a cooling device for Bingham liquids Expired - Lifetime EP0688599B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9402194 1994-06-22
SE9402194A SE502118C2 (en) 1994-06-22 1994-06-22 Liquid agitator, which comprises an electric motor and a propeller and is intended to operate immersed in the working medium

Publications (2)

Publication Number Publication Date
EP0688599A1 true EP0688599A1 (en) 1995-12-27
EP0688599B1 EP0688599B1 (en) 1998-08-12

Family

ID=20394478

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95850101A Expired - Lifetime EP0688599B1 (en) 1994-06-22 1995-06-07 Mixer with a cooling device for Bingham liquids

Country Status (6)

Country Link
EP (1) EP0688599B1 (en)
JP (1) JPH0838874A (en)
AU (1) AU682589B2 (en)
CA (1) CA2152293A1 (en)
DE (1) DE69503981T2 (en)
SE (1) SE502118C2 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56161893A (en) * 1980-05-15 1981-12-12 Kurimoto Iron Works Ltd Axial-flow aerator for aeration
EP0286611A1 (en) * 1987-04-06 1988-10-12 ITT Flygt Aktiebolag A submersible mixer with oscillating device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56161893A (en) * 1980-05-15 1981-12-12 Kurimoto Iron Works Ltd Axial-flow aerator for aeration
EP0286611A1 (en) * 1987-04-06 1988-10-12 ITT Flygt Aktiebolag A submersible mixer with oscillating device

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 6, no. 49 (C - 96)<927> 31 March 1982 (1982-03-31) *

Also Published As

Publication number Publication date
JPH0838874A (en) 1996-02-13
DE69503981D1 (en) 1998-09-17
DE69503981T2 (en) 1998-12-17
SE9402194D0 (en) 1994-06-22
SE9402194L (en) 1995-08-21
CA2152293A1 (en) 1995-12-23
AU2016395A (en) 1996-01-04
EP0688599B1 (en) 1998-08-12
SE502118C2 (en) 1995-08-21
AU682589B2 (en) 1997-10-09

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