US3905557A - Crushing roller mill protective method and system - Google Patents

Crushing roller mill protective method and system Download PDF

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Publication number
US3905557A
US3905557A US471966A US47196674A US3905557A US 3905557 A US3905557 A US 3905557A US 471966 A US471966 A US 471966A US 47196674 A US47196674 A US 47196674A US 3905557 A US3905557 A US 3905557A
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United States
Prior art keywords
oil
temperature
mill
level
sump
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Expired - Lifetime
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US471966A
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English (en)
Inventor
Helmut Grommes
Willi Lehr
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Deutsche Babcock and Wilcox AG
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Deutsche Babcock and Wilcox AG
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C23/00—Auxiliary methods or auxiliary devices or accessories specially adapted for crushing or disintegrating not provided for in preceding groups or not specially adapted to apparatus covered by a single preceding group
    • B02C23/04—Safety devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C15/00—Disintegrating by milling members in the form of rollers or balls co-operating with rings or discs
    • B02C15/004—Shape or construction of rollers or balls

Definitions

  • This invention relates'to'crushing roller mills and more particularly to a security method and system for protecting such mills against excessive 'grinding plate, crushing roller or bearing .wear.
  • Particularly advantageous utility of the protection 'me'thod and system of this invention is found with'rnills'of the type comprising a horizontally rotating"grindingplate' and stationary, that is, nonorbiting, crushing rollers rolling over it and transferring grinding pressure I to the grinding plate while attached to a shaft by means of 'an'oil lubricated bearing.
  • the protection and security method and system of this invention utilizes the normal start up and stopping devices of the mill.
  • the system includes several temperature measuring primaryelectrical elements, protected by a metal shell, as well as several electrical remote indicating control devices which react to temperature changes of the primary elements or to changes in capacitance. These remote indicating control devices may, if desired, be connected to' alarm devices for warning control.
  • a temperature feeler located in the oil sump of the splash lubrication means of the roller bearing and which dips into the oil therein.
  • the temperature feeler is advantageously positioned within a bore in each crushing roller shaft and connected to a remote control measuring device.
  • the temperature feeler is surrounded by a pol' ished metal shield or shell which is electrically insulated from the shaft bore and together with the bore forms two capacitor surfaces opposite one another with an annular space therebetween.
  • the oil of the sump penetrates into the annular space, that is, the oil rises within the annularspace to a height of the oil level in the sump, and functions as a dielectric between the capacitor surfaces so that changes in capacitance occur with changes in oil level.
  • the metal shell and bore are connected to a remote control measuring device which reacts to changes in the capacitance.
  • the mill Upon receiving an indication that the temperature has fallen by more than a predetermined amount or that the oil level has risen by more than a predetermined amount, the mill is stopped so that the crushing roller may be rolled back over a short distance to remove the particularly hard fragment or foreign body. This is accomplished by turning the rotating grinding plate back to free the fragment so that when the mill is started up again, the fragment or foreign body is pushed out of the grinding strip by the crushing roller or jumps free of it.
  • the oil level in the sump should be observed because this characteristic reacts faster to indicate normal operation then does an increase in temperature after start up. If the sump oil level observed does not drop and hence indicates that the roller is not free, the mill must be stopped again and then once again started up.
  • Another object of this invention is the provision of a method and system for observing the oil level in the sump of a crushing roller splash lubrication system in order to determine whether or not the crushing roller is operating free from blockage.
  • a drop in temperature of the oil of the splash lubrication system of the crushing roller can be better ascertained, according to this invention, by advantageously continuously comparing the oil temperature of the bearings of all the crushing rollers of the mill operating under the same conditions.
  • the measured oil temperature of the blocked crushing roller then will show the actual temperature while the other oil'temperature will show how high the oil temperature of the blocked crushing roller should be if it is operating properly.
  • a yet further object of this invention is the provision of a method and system of a continuously measuring oil temperature conditions of oil in splash lubrication systems of all the rollers of a crushing roller mill in order to determine whether they are all operating the same.
  • the temperature measuring feeler of this invention assumes the temperature of the oil by transmission of .heat therefrom and this temperature may be visibly indicated on an electric measuring instrument through the electric remote control measuring device of this system.
  • the capacitance of the capacitor formed from the metal shell and the bore changes with the height of the oil level because in this area of the capacitor the dielectric constant of the lubricating oil becomes operative.
  • the capacitance is approximately doubled by the lubrieating oil.
  • the change in oil level causes a change in the capacitance and this may be indicated through measurement of the capacitance by a remote control measuring device on an electric measuring instrument.
  • another object of this invention is the provision of a protective method and system providing continuous monitoring and control of the oil levels and of the oil temperature in a crushing roller bearing splash lubrication system and yielding early warning signals indicating the need to be on the lookout for imminent damage to the bearing and the crushing roller in order to obtain an improvement in the operation of the mill through a great decrease in the grinding of flat surfaces at the circumference of crushing rollers and thus avoiding excessive wear and costly downtime maintenance.
  • FIG. 1 shows a partial cross-sectional view taken through a crushing roller mill showing the crushing roller, the crushing roller shaft and lubrication system and the rotating grinding plate;
  • FIG. 2 is a schematic diagram illustrating the electrical system permitting continuous monitoring and control of the oil levels and oil temperatures of the crushing roller bearings.
  • FIG. 1 there is shown, in partial crosssection, a single crushing roller, A of a mill comprising three crushing rollers A,, A and A
  • the crushing rollers are non-orbiting," and roll on an annular grinding strip 1 of a horizontally rotating plate 2 which is driven by a motor 3 via a drive 4, as shown diagrammatically in FIG. 1.
  • a switch 5, also shown diagrammatically, is illustrative of a common device for starting and stopping the mill.
  • the crushing roller A is illustrative of the remaining crushing rollers A and A of the mill and they comprise like elements.
  • FIG. 1 The drive of the mill can best be -illustrated on the basis of the attached drawings.
  • FIG. 1 show a plan view and a side view of a crushing roller mill embodying the present invention.
  • the crushing rollers A A and A are stationary in relation to the housing of the mill. They roll on the annular strip 1 of a horizontal revolving plate 2. Plate 2 is driven by the electric motor 3 via gear 4. In the power supply to the electric motor 3 there is a switch 5 by which the starting and stopping of the mill are monitored from a control position.
  • the crushing roller A is attached to a shaft 7 which permits it to rotate, by a combined roller bearing fi, for
  • the hub of the crushing roller seals the bearng 6 and the end of the shaft 7 in a housing which is filled with oil up to the level indicated at B
  • the oil fill forms;a sump, shown at D of a splash lubrication system into which the rollers of the bearings dip and through which they pass upon rotation of the crushing roller. This passage of the roller bearing 6 through the oil in the sump D brings part of the oil therein up for lubrication.
  • a temperature measuring feeler 8 is provided which is surrounded by a polished bright metal jacket 9 and which dips or penetrates beneath the level of the oil of the sump D
  • the temperature measuring feeler 8 is connected, through electrical wiring, to the measuring device 10 and an indicating instrument E which indicates the oil temperature.
  • the metal jacket is connected to a remote control measuring device 11 and a measuring instrument F which indicates the oil level through an electrical circuit.
  • the metal jacket 9 is positioned within bore 12 of the shaft 7 so that it is electrically insulated from the bore and forms together with the bore two opposite capacitor surfaces with an annular space 13, into which the oil of the sump D penetrates, to the height of the oil level B from below.
  • the bore 12 is connected with the bearing space by a cross bore 12' for the equalization of pressure therein so that the oil level may rise and fall therein in relationship to its rising and falling in the sump D
  • oil is in the annular space 13 so that the capacitance of this area of the capacitor is doubled due to the dielectric constant of the lubrication mineral oil.
  • FIG. 2 there is shown diagrammatically the temperature measuring and oil level measuring elements together with telemetering circuits utilized for providing continuous remote monitoring and control of the oil level and temperatures of the oil in the splash lubrication system. These are shown corresponding to the three rollers, A A and A of the crushing mill.
  • the feelers 8 are apart of the Wheatstone bridges 10 in which the indicators E E or E measure the bridge current present and through appropriate calibration provide indication of the temperature at a remote location.
  • the feelers 8 generate an electrical signal related to the temperature.
  • the telemetering devices, indicated generally at 11, that react to capacitance changes comprise a high frequency generator, the oscillatory circuit of which, con sisting of an inductive reactance and a high frequency generator, is stimulated by direct current via a coupledback transistor.
  • a high frequency generator the oscillatory circuit of which, con sisting of an inductive reactance and a high frequency generator, is stimulated by direct current via a coupledback transistor.
  • These elements are shown schematically and are known in the art, as indicated earlier therein.
  • the capacitor formed by the metallic jacket 9 together with the bore 12 is part of the oscillatory circuit.
  • the oscillation frequency changes when the capacitance changes through a change in the oil level from B to 8' or the reverse thereof.
  • the oscillation frequency of the high frequency generator 15 is transmitted connected by means of a Wien-Robinsons bridge circuit 16, built up from resistors and capacitors, which is coordinated with the oscillation frequency of the high frequency generator 15 to indicate change in the oscillation frequency by a voltage change in the bridge potential.
  • a direct current circuit is controlled with this voltage potential with the aid of a transistor which supplies the measured value for the recording element F
  • the capacitor formed of the jacket 9 and bore 12 generates an electrical signal related to the oil level.
  • the recording element F indicates the oil level and when it has risen from 8' to B
  • Constant monitoring and operating control is cffected by assuring that the indicators E E and E which can be coupled to warning devices or other cir cuit devices, for control, show that the temperature of the oil in the sumps D D and D does not rise too much, that is, above a predetermined value, dependent upon the operating condition of the particular mill, and further through observing the recording elements F F and F to be sure that the oil level 8' 8' and B;, does not sink too low, that is, below a predetermined level dependent upon the operating condition of the particular mill as a result of oil lossin the sump.
  • the mill is stopped through operation of the switch shown schematically in FIG. 1 and started up again by switching the switch on.
  • This starting and stopping will cause any particularly hard fragments that may block the crushing roller or foreign bodies to be pushed aside or flung out of the grinding track.
  • the indicator F shows a drop in the oil level from B to B since this is the most responsive characteristic upon start-up to make sure that possible damage to the bearing does not occur in the rotation of the crushing roller.
  • the same protective and safety precautions are taken in a similar manner when the other crushing roller A or A may be blocked.
  • a method for monitoring and controlling the operation of a crushing roller mill of the type including a rotating horizontal plate having an annular grinding strip over which roll one or more non-orbiting crushing rollers rotatably mounted to shafts by means of bearings splash lubricated by oil contained in a sump within the crushing roller bearing housing comprising continuously measuring at least one of the temperature and the level of the oil in the sump of at least one of the rollers,
  • a method as claimed in claim 1 comprising mea- 'suring at least one of the temperature and the level of foregoing measurements for all of said rollers determining if said compared measurements of one roller differ by a predetermined amount from those of the other rollers, and stopping the operation of the mill in response thereto.
  • a crushing roller mill of the type including a rotating horizontal plate having an annular grinding strip over which roll one or more non-orbiting crushing rollers rotatably mounted to shafts by means of bearings splash lubricated by oil contained in a sump within the crushing roller bearing housing
  • the improvement comprising a system for monitoring the operation of the mill to protect it against unnecessary wear or breakdown comprising temperature measuring means positioned in the sump for measuring the temperature of the oil therein, signal generating and transmitting means operatively connected to the temperature measuring means for generating and transmitting a signal related to the temperature measured, control means responsive to the temperature signal for controlling the operation of the mill.
  • a crushing roller mill of the type including a rotating horizontal plate having an annular grinding strip over which roll one or more non-orbiting crushing rollers rotatably mounted to shafts by means of bearings splash lubricated by oil contained in a sump within the crushing roller bearing housing
  • the improvement comprising a system for monitoring the operation of the mill to protect it against unnecessary wear or breakdown comprising oil level measuring means positioned in the sump for measuring the level of the oil therein, signal generating and transmitting means operatively connected to the boil level measuring means for generating and transmitting a signal related to the oil level measured, control means responsive to the oil level signal for controlling the operation of the mill.
  • the oil level measuring means comprises a capacitor means having opposite capacitor surfaces penetrating below the level of the oil in the sump between which the oil acts as a dielectric so that the capacitance varies with the level of the oil
  • the signal generating means comprises a telemetering means including an oscillatory circuit means the oscillation frequency of which changes with the capacitance changes brought about by an oil level change, circuit means relating the oscillation frequency to a voltage potential and the control means includes means for acting in response to the voltage potential.
  • a crushing roller mill of the type including a rotating horizontal plate having an annular grinding strip over which roll one or more non-orbiting crushing rollers rotatably mounted to shafts by means of bearings splash lubricated by oil contained in a sump within the crushing roller bearing housing
  • the improvement comprising .a system for monitoring the operation of the mill to protect it against unnecessary wear or breakdown comprising providing a crushing roller shaft having an axially longitudinal bore therein arranged in communication with the sump so that oil in the sump rises in the bore, a resistance-type temperature measuring feeler means positioned in the bore to penetrate beneath the surface of the oil for measuring the temperature of the oil-in the bore, a metal jacket means surrounding the temperature measuring feeler means concentrically positioned within the bore and forming an annular space therebetween, the metal jacket means viding an electrical signal output related to the oil level, indicating means responsive to the temperature and oil level signal means for indicating when the temperature or oil level varies from a predetermined value.
  • the mill includes means for continuously comparing the same in each roller and determining whether one differs by a predetermined amount from the other.

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Crushing And Grinding (AREA)
US471966A 1973-05-24 1974-05-21 Crushing roller mill protective method and system Expired - Lifetime US3905557A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2326470A DE2326470C2 (de) 1973-05-24 1973-05-24 Rollenquetschmühle

Publications (1)

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US3905557A true US3905557A (en) 1975-09-16

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US471966A Expired - Lifetime US3905557A (en) 1973-05-24 1974-05-21 Crushing roller mill protective method and system

Country Status (9)

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US (1) US3905557A (de)
AT (1) AT324813B (de)
CS (1) CS170108B2 (de)
DD (1) DD114352A1 (de)
DE (1) DE2326470C2 (de)
GB (1) GB1423936A (de)
IN (1) IN141212B (de)
YU (1) YU35716B (de)
ZA (1) ZA743303B (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3984055A (en) * 1974-12-04 1976-10-05 Morehouse Industries, Inc. Sandmill control system
WO2002040169A1 (de) * 2000-11-15 2002-05-23 Svedala Lindemann Gmbh Verfahren und anlage zur zerkleinerung von abfall
US20070216395A1 (en) * 2003-06-25 2007-09-20 Koninklijke Philips Electronics N.V. Method and Circuit Arrangement for the Self-Testing of a Reference Voltage in Electronic Components
JP2013542073A (ja) * 2010-11-08 2013-11-21 アルストム テクノロジー リミテッド 微粉砕機の動作特性を監視するためのシステムおよび方法

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2612390C2 (de) * 1976-03-24 1984-08-16 Deutsche Babcock Ag, 4200 Oberhausen Tauchschmierung
DE2742678A1 (de) * 1977-09-22 1979-04-05 Babcock Ag Mahlwalze
US8500052B2 (en) * 2008-11-26 2013-08-06 Flsmidth A/S Roller mill for grinding particulate material

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1808914A (en) * 1929-08-16 1931-06-09 Nordberg Manufacturing Co Automatic control for cone crushers
US3138337A (en) * 1963-03-26 1964-06-23 Combustion Eng Pulverizing bowl mill utlizing a segmented bull ring
US3350018A (en) * 1963-12-16 1967-10-31 Dominion Eng Works Ltd Grinding mill control or the like
US3471094A (en) * 1966-12-01 1969-10-07 Terry R Kearney Hydraulic control system for mills

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1808914A (en) * 1929-08-16 1931-06-09 Nordberg Manufacturing Co Automatic control for cone crushers
US3138337A (en) * 1963-03-26 1964-06-23 Combustion Eng Pulverizing bowl mill utlizing a segmented bull ring
US3350018A (en) * 1963-12-16 1967-10-31 Dominion Eng Works Ltd Grinding mill control or the like
US3471094A (en) * 1966-12-01 1969-10-07 Terry R Kearney Hydraulic control system for mills

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3984055A (en) * 1974-12-04 1976-10-05 Morehouse Industries, Inc. Sandmill control system
WO2002040169A1 (de) * 2000-11-15 2002-05-23 Svedala Lindemann Gmbh Verfahren und anlage zur zerkleinerung von abfall
US20040056126A1 (en) * 2000-11-15 2004-03-25 Metso Lindemann Method and installation for comminuting scrap material
US6766971B2 (en) 2000-11-15 2004-07-27 Metso Lindemenn Gmbh Method and installation for comminuting scrap material
US20070216395A1 (en) * 2003-06-25 2007-09-20 Koninklijke Philips Electronics N.V. Method and Circuit Arrangement for the Self-Testing of a Reference Voltage in Electronic Components
US7394239B2 (en) * 2003-06-25 2008-07-01 Nxp B.V. Method and circuit arrangement for the self-testing of a reference voltage in electronic components
JP2013542073A (ja) * 2010-11-08 2013-11-21 アルストム テクノロジー リミテッド 微粉砕機の動作特性を監視するためのシステムおよび方法

Also Published As

Publication number Publication date
ZA743303B (en) 1975-06-25
YU35716B (en) 1981-06-30
DD114352A1 (de) 1975-08-05
IN141212B (de) 1977-01-29
AT324813B (de) 1975-09-25
YU121074A (en) 1980-12-31
CS170108B2 (de) 1976-08-27
DE2326470C2 (de) 1982-09-16
DE2326470A1 (de) 1974-12-12
GB1423936A (en) 1976-02-04

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