Since the equilibrium moisture content of wood in Shanghai is 14.8%, the floor moisture content used in Shanghai should be controlled at 7% to 14.8%.
process
(1) Natural drying takes about 30 to 40 days to bring the moisture content to about 30%.
(2) Artificial drying takes about 10 to 30 days so that the moisture content is below 10%. This process also distilled the pulp from the wood and balanced the wood cell wall structure. The dry shrinkage performance tended to be stable and consistent.
(3) Health treatment takes about 10 to 20 days. Through this process, the three purposes of wood drying are finally achieved.
Dry equilibrium treatment is so-called heat treatment. The length of this treatment will vary from material to material, but it cannot be artificially shortened. There is a wrong statement in sales that the heat treated floor is "never deformed." In fact, this is impossible. Regardless of how it is handled, the phenomenon of bloated shrinkage that occurs when the moisture content of wood is changed below the saturation point of the fiber is unavoidable.
Building Materials Knowledge Home Maintenance Nature Flooring
Set screw is also called head screw and positioning screw. The utility model is a screw specially used for fixing the relative position of machine parts. Type: square flange end set Bolt, GB / t821-1988 square chamfered end set screw, GB / t85-1988 square long cylindrical end set screw, inner square head set screw, etc.
Related categories
Hexagon socket set screw, hexagon flat set screw, hexagon cylindrical set screw.
The selection of common set Screws is generally used to fix the relative position of two parts with little force. The axial and circumferential positioning of common sleeve like parts on the shaft. There are many kinds of set screws. The common ones are as follows: according to the end part, there are conical end, flat end, concave end, oblong cylinder head, etc;
According to the head part: slotted, hexagon socket, square head, etc. Tapered end screws and concave end screws with sharp ends can be used to directly top the parts, and the concave end is more reliable and can bear greater force; Taper end screws without sharp points must be drilled in the parts. The flat end is used to top the tight plane, which does not damage the parts, but bears limited load.
Slotted screws have small tightening force and are often easy to screw off. Generally, they prefer hexagon socket head; The tightening force of square head is the largest, but it can not be embedded in parts, and its use is limited. In order to prevent loosening and withdrawal of threaded parts, a set screw can be drilled at the cross seam. The long cylindrical head screw at the top end is used in the keyway of the shaft to lock and prevent circumferential rotation. It can also be used in general unimportant occasions when the key slides in the keyway of the shaft.
Set Screws,Allen Nose Set Screw,Slotted Head Set Screw,Hexagon Socket Grub Screw
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