Convective hot-air chambers impulse drying of pear wood lumbers

A review of literary sources on the physical and mechanical properties of pearwood and its use as structural elements of furniture is given. The aerodynamic chambers, their advantages and disadvantages, as well as their modernization are considered. The use of impulse modes for drying hardwood is substantiated, including sawn timber from pear wood 50 mm thick, pilot drying of which began in the modernized URAL-72 chamber in 1999 at Intar LLC, Moscow. The moisture content of the wood samples and the value of internal stresses were controlled in accordance with GOST 16588. The process of impulse drying included from 9 to 12 steps, the temperature at the operating stage ranged from 45 °C to 72 °C. It has been proved that the use of pulse modes for drying pear timber saves up to 30% of electricity.

Liquid Ring Vacuum Pumps for Heat and Mass Transfer Processes

The paper examines the calculation of a liquid ring vacuum pump, using the example of the drying process of various materials. It was found that for two-stage convective vacuum-impulse drying it is economically efficient to use a two-stage liquid ring vacuum pump with the ability to turn off the second stage. A method for calculating the specific power of one-stage and two-stage liquid ring vacuum pumps, taking into account heat and mass transfer and thermal processes that occur during operation is proposed.