CS237069B1 - Method of chemical and mechanical removal of incrustation remainders from pressing plates - Google Patents

Abstract

Incremental Removal Method of the invention prevents surface damage pressing plates, the action is prolonged their lifespan. Significantly shorter incrustation removal time using swelling agents at 20 to 38 ° C. The swelling agent is used aqueous sodium hydroxide solution; sodium chlorite with acetic acid or machine oil.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention

The inks that are produced in the dry process of the fibreboard cover the surface of the press plates, making it difficult for the presses to operate smoothly and not only deteriorate the press plate surface, but also the surface of the produced fibreboard. Mechanical scaling is difficult. The inks are adhered very firmly to the surface of the press plates, and the hitherto known removal methods damage the high smooth surface of the functional press plate surfaces. Current incrust removal procedures are laborious and time consuming.

Disadvantages of the prior art processes are largely eliminated by the method of chemical-mechanical removal of the inlay from the press plates according to the invention, which is based on the fact that the surface of the press plates covered with inks is treated with a swelling agent at 20 to 380 ° C for 20 to 600 minutes thereafter, chemically disturbed incrusts are removed mechanically, preferably by wiping

By using the method according to the invention, the mechanical removal of hard incrusts with the consequent possibility of damaging the surface of the press plates is eliminated. The time to remove the inlay is considerably shorter, as chemical breakdown is usually performed at *

end of the production cycle. Savings arise due to the longer lifetime of the pressing plates and the lower share of working downtime.

The pressing plates are covered with a layer of hard inks after a certain period of operation. The removal of these incrusts is carried out according to the invention by exposing them to a solvent which simultaneously has a delignifying effect at an elevated temperature. Incrusts after pre-swelling respectively. partial dissolution changes

237 069 its properties. Inorganic * or organic substances capable of dissolving lignin, preferably aqueous solutions of strong alkaline hydroxides such as sodium, potassium, or chlorite solutions in an acid medium serve as blowing agents. * Partial swelling of the incrusts also occurs in the machine oil · After exposure to heat and swelling agents the increments are removed from the surface of the plates by mechanical means, e.g. by wiping.

Example 1

The press platens covered with increments are sprayed with an excess of 5% sodium hydroxide solution and heated to 80-105 ° C.

After 60 minutes of multiplication, the swollen layer of crusts is wiped off by mechanical action of the scalp, which moves just above the surface of the pressing plates, so that its edges do not affect the plate surface and do not destroy it,

Example 2

The press platens coated with increments are sprayed with an aqueous solution containing 6% sodium chlorite and 2% acetic acid. The solution is allowed to react at 50 ° C for 240 minutes. Subsequently, the incrusts are removed mechanically as in Example 1.

Example 3

The press platens are coated with an excess of machine oil, which is left to operate at 80 to 90 ° C for 120 minutes. Then the plates are heated to 380 ° C and the machine oil is left to continue for 20 minutes. in example 1 ·

The present method of chemico-mechanical removal of acrusts from the pressing plates can advantageously be applied in all plants by dry-pressing wood-fiber boards.

Claims (4)

OBJECT OF THE INVENTION 237 069 «Process of chemical-mechanical removal of inks from press plates in the manufacture of fibreboard by a dry process, characterized in that the surface of the press plates covered with inks is treated with a swelling agent at a temperature of 20 to 380 ° C for 20 to 600 minutes» remove chemically disturbed incrusts mechanically, preferably by wiping, 2. A process according to claim 1, characterized in that an aqueous sodium hydroxide solution of 1 to 18% is used as the swelling agent. Process for the chemical-mechanical removal of increments from the press plates according to claim 1, characterized in that an aqueous solution containing 3 to 15% sodium chlorite and 0.5 to 5% acetic acid is used as the swelling agent. 4. A process for the chemical-mechanical removal of increments from the press plates according to claim 1, characterized in that machine oil is used as the swelling agent.