PROCESSING OPERATIONS IN FOREST-BASED INDUSTRIES IV-B

Question 1

the process of drying wood by mechanical or natural means

Answer 1

WOOD SEASONING

Question 2

OBJECTIVES OF WOOD SEASONING

Answer 2

• reduce the occurrence of wood defects
• minimize effect of shrinkage and swelling of wood
• increase strength properties of wood
• facilitate application of preservatives
• improve machining and finishing qualities
• increase thermal and electrical resistance
• improve nail holding capacity of wood
• reduce weight for easy transportation and handling
• enhance resonance quality of wood for acoustic applications
• reduce bond failure in glued-wood products

Question 3

METHODS OF WOOD SEASONING

Answer 3

a. Natural drying
b. Artificial drying

Question 4

Natural drying:

Answer 4

i. Air seasoning
ii. Water seasoning
iii. Solar seasoning

Question 5

• oldest, traditional and simplest method of seasoning wood
• based on the principle that the piece of timber is stacked in a way to allow plenty of air to circulate around each piece of timber

Answer 5

Air seasoning

Question 6

• process of placing logs in a river with thicker ends pointing upstream side of the river for seasoning purposes
• the sap of the timber is washed over a span of 2-4 weeks by the river water

Answer 6

Water seasoning

Question 7

• a solution provided for the low energy requirement of air drying and the speedy operation of kiln drying
• slower and gentler form of kiln drying

Answer 7

Solar seasoning

Question 8

Artificial drying:

Answer 8

i. Seasoning by boiling
ii. Chemical seasoning
iii. Electrical/ Rapid seasoning
iv. Kiln seasoning

Question 9

drying of wood thru mechanical means or with the use of equipment and/or chemicals

Answer 9

Artificial drying

Question 10

• wood is immersed in water and then boiled for about 3 – 4 hours under supervision
• the needed amount of sap in the water is removed during boiling

Answer 10

Seasoning by boiling

Question 11

• timber is stored in suitable salt solution for some time
• the salt solution used has the tendency to absorb water from the timber
• So, the MC is removed and then timber is allowed to drying

Answer 11

Chemical seasoning

Question 12

• timber is subjected to high frequency alternating currents
• the resistance of timber against electricity is measured at every interval of time

Answer 12

Electrical/ Rapid seasoning

Question 13

• seasoning of wood in a chamber using artificially controlled temperature and humidity
• the hot air circulates in between the timber logs and reduces the moisture content

Answer 13

Kiln seasoning

Question 14

Kiln seasoning:

Answer 14

a. Progressive kiln seasoning
b. Compartmental kiln seasoning

Question 15

• timber enters at one end and moves progressively through the kiln much as car moves through a tunnel

Answer 15

Progressive kiln seasoning

Question 16

Progressive kiln seasoning:

Answer 16

a. Draft kilns
b. Forced draft kilns

Question 17

– heated air is allowed to rise through the material by natural convection

Answer 17

Draft kilns

Question 18

– fans are employed to force the air through the wood

Answer 18

Forced draft kilns

Question 19

• a single enclosed container or building, etc.
• the timber is loaded into the kiln and remains in place throughout the drying process
• a kiln in which the total charge of lumber is dried as single unit

Answer 19

Compartmental kiln seasoning

Question 20

• process employed to prevent drying defects during kiln drying

Answer 20

KD Quality Control

Question 21

KD Quality Control:

Answer 21

a. Conditioning treatment
b. Equalization treatment

Question 22

– steam introduced to relieve stresses prior to end of KD

Answer 22

Conditioning treatment

Question 23

– temperature is lowered with steam to have a more uniform final MC of stocks

Answer 23

Equalization treatment

Question 24

• QC test performed to determine drying stresses in wood

Answer 24

Prong test

Question 25

– occurs when the core is in tension while the surface is in compression

Answer 25

Casehardening

Question 26

• are carefully worked-out set of progressively increasing kiln temperature and decreasing relative humidity which a KD operator can use as a guide to dry specific wood products at a satisfactorily rate without causing objectionable drying defects

Answer 26

KILN DRYING SCHEDULES

Question 27

KILN DRYING SCHEDULES:

Answer 27

a. General KD schedules
b. Special KD schedules

Question 28

– employed for lumber used in general construction

Answer 28

General KD schedules

Question 29

– developed to attain specific objectives for special uses

Answer 29

Special KD schedules