Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01G—WEIGHING
  • G01G19/00—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01G—WEIGHING
  • G01G13/00—Weighing apparatus with automatic feed or discharge for weighing-out batches of material
  • G01G13/02—Means for automatically loading weigh pans or other receptacles, e.g. disposable containers, under control of the weighing mechanism
  • G01G13/14—Arrangements for determination of, or compensation for, the tare weight of an unloaded container, e.g. of a disposable container
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01G—WEIGHING
  • G01G23/00—Auxiliary devices for weighing apparatus
  • G01G23/14—Devices for determining tare weight or for cancelling out the tare by zeroising, e.g. mechanically operated
  • G01G23/16—Devices for determining tare weight or for cancelling out the tare by zeroising, e.g. mechanically operated electrically or magnetically operated
  • G01G23/163—Devices for determining tare weight or for cancelling out the tare by zeroising, e.g. mechanically operated electrically or magnetically operated involving digital counting

Definitions

• the present invention relates to a method for measuring the quantity of the periodically dried product, and particularly the quantity of a concentrate dried in a pressure filter.
• the method comprises the fol ⁇ lowing , periodically repeated stages : inserting the product to be dried in the drying apparatus, carrying out the successive drying stages , and discharging the dried product from the drying apparatus.
• the present invention is particularly well suited to be employed in connection with concentrate drying , but naturally its scope is not lim ⁇ ited to this one exemplary case only.
• Such pressure filters that are suited for drying concentrates are manufactured for example by Larox Oy.
• the drying operation consists of three stages.
• the slurry is conducted through the filter cloth , so that the cloth separates the solid particles of concentrate from the slurry.
• the slurry flow is interrupted, and the layer of concentrate formed on the filter cloth is squeezed in order to re ⁇ cute the volume of the filter cake and to remove liquid therefrom.
• the filter cake is further dried by blowing air through the cake. Thereafter the filter cake is discharged from the pressure filter.
• the dried concentrare is further transported , pre ⁇ ferably by means of a conveyor band , to the desired location .
• a customary method for measuring the concentrate quantity during transport in the band conveyor is to employ a belt weigher.
• the belt weigher does not function accurately enough owing to the periodical nature of the operation of the pressure filter.
• the present invention is characterized by the novel features presented in the patent claims .
• the concentrate quantity can be measured quickly and accurately and without interfering with the process itself.
• the capacity of the above described pressure filter is dependent on the length of the respective filtering , squeezing, air-blow drying and discharge stages.
• the method of the invention also makes it possible to run the pressure filter at optimum readings, in which case the capacity of the pressure filter is utilized more effi- cfently.
• the diagram of the drawing illustrates the drying of concentrate by employing a pressure filter manufactured by Larox Oy, and to be more precise, it illustrates one drying cycle of the pressure filter.
• the drying of the concentrate is started in the filtering stage 1 , where the concentrate, in liquid suspension , is filtered by means of the filter cloth .
• the length of the filtering stage may vary according to the material to be filtered .
• the chosen filtering time may be a minute.
• the concentrate flow is interrupted , and the layer of concentrate which is accumulated on the filter cloth undergoes the squeezing stage 2.
• Squeezing is carried out by means of a rubber film and by utilizing liquid pressure. In practice the length of the squeezing stage may vary as well , and it can be for instance a min ⁇ ute.
• the filter cake undergoes air-blow drying 3.
• the length of the air-blow drying stage is , accordingly, dependent on the qualities of the material in question , but in practice a suitable dura ⁇ tion is for example five minutes.
• the drying phase proper is completed , and the filter cake is ready to be discharged from the press .
• the whole press is weighed along with the concen ⁇ trate contained therein .
• the weighing 4 is best carried out so that the press apparatus is attached on top of suitable square beams which are for instance 100 mm high .
• the said beams are provided with measuring sensors , which may be for instance piezoelectric weighing sensors of the commercially available type.
• the concentrate is discharged, 5 , from the press.
• the obtained concentrate is further transported to the desired location by means of a conveyor band .
• the duration of the discharge stage is 10 - 12 seconds.
• a new weighing 6 is carried out.
• the weighing result is again recorded in the microprocessor 7.
• the microprocessor carries out the subtraction of the two readings , and the obtained result is the weight of the batch in question .
• the above described operations are carried out in periods .
• the micro ⁇ processor records the reading fed therein , and thus the concentrate quantities are accessible in the desired form and stage.
• the most re- markable advantage of the invention is that by means of the history recording , the pressure filter may be adjusted to function exactly at the desired optimum readings. This in turn has a direct influence in the capacity of the filter press , and consequently the method of the invention is of considerable economic importance.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Sampling And Sample Adjustment (AREA)
• Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Drying Of Solid Materials (AREA)
• Investigating Or Analyzing Materials Using Thermal Means (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

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Family Applications (1)

Country Status (6)

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Citations (6)

Family Cites Families (7)

• 1985
  • 1985-02-22 FI FI850728A patent/FI76639C/fi not_active IP Right Cessation
• 1986
  • 1986-02-20 DE DE8686901873T patent/DE3665933D1/de not_active Expired
  • 1986-02-20 WO PCT/FI1986/000020 patent/WO1986004985A1/en active IP Right Grant
  • 1986-02-20 EP EP86901873A patent/EP0214259B1/en not_active Expired
  • 1986-02-20 AU AU55829/86A patent/AU591482B2/en not_active Ceased
  • 1986-02-20 US US06/916,501 patent/US4749054A/en not_active Expired - Lifetime

Patent Citations (6)

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