Abstract: Disclosed is a shut-off valve installed in an accommodation chamber regulating entry/exit of air. The shut-off valve includes: a body removably disposed in the accommodation chamber and having multiple air passage holes; a valve stem adapted to be moved vertically along a valve stem insertion hole formed in the body; a disc mounted on a disc engagement portion formed at a lower end of the valve stem to open/close at least one of the multiple air passage holes; a rotor disposed on an upper side of the body to vertically move the valve stem, the rotor being provided with an opening/closing indicator to check opening/closing of the shut-off valve outside the accommodation chamber, wherein the accommodation chamber has an upper wall, a lower wall, and a side wall, the body disposed passing through the upper wall and lower wall of the accommodation chamber, and the disc is located outside the accommodation chamber.

Abstract: Provided are an abrasion-detection type conveyor belt and a manufacturing method thereof. A polymer composition ratio of is set to 40-60% of styrene-butadiene rubber (SBR) and 60-40% of natural rubber (NR), and an adhesive strength between a cover rubber layer and an abrasion-detection color layer is set to 13 kN/m (33 kgf/inch). As compared to the existing product, material properties of the abrasion-detection color layer are improved to extend the available life of the abrasion detection type conveyor belt. The abrasion-detection type conveyor belt is cost-effective, simplifies a belt line, and reduces an inspection time.