เกียวกับ สายยางอุตสาหกรรม
Hose จัดเป็นอุปกรณ์ประกอบที่ไม่ถาวร เพราะมีการสึกหรอ มีการกัดกร่อน มีการเสื่อมตามอายุของวัสดุที่ทำ จึงต้องตรวจสภาพและทำการเปลี่ยนบ่อยๆ ถ้าใช้กับขนส่งวัตถุไวไฟ กรด ด่าง วัตถุมีพิษ หรือสารอันตราย การรั่วไหลจาก Hoses สู่ภายนอก อาจเป็นต้นเหตุให้เกิดเพลิงไหม้ บาดเจ็บ หรืออันตรายต่อบุคคล ทรัพย์สิน หรือสิ่งแวดล้อม
การก่อสร้าง - Construction
Hoses are constructed using three basic parts:
- A plastic or rubber tube or inner lining which makes contact with the fluid.
- A textile, plastic, or metal body or carcass which reinforces the structure of the hose to withstand internal and external pressures.
- A rubber, plastic, metal, or textile cover which protects against damage due to wear, abrasion, and the environment.
Although there are innumerable specific hose designs for different applications, there are four basic types of hose construction found in industry:
- Vertical braided hose - the entire hose length is cured in one operation for good flexibility, high kinking resistance, and excellent tensile strength.
- Spiral hose - the hose is built by machine with wire reinforcement so that each ply is laid at a given angle. This allows for extreme flexibility, high strength, and maximum dimensional stability.
- Hand built spiraled ply hose - the hose is built by hand and cured under pressure applied from outside. These hoses are built to specific requirements, with wide variations in sizes, constructions, and materials.
- Knitted hose - the hose consists of a seamless tube with a seamless woven textile jacket for reinforcement. These hoses are very flexible, lightweight, crush and kink resistant, and do not change length under pressure.
Size
Sizing is the most basic and essential factor in industrial hose selection. Sizing specifications for industrial hose include inner diameter, outer diameter, and length.
Inner Diameter
Inner diameter (I.D.) is the span of the empty space in a circular hose cross section. It is the most important factor in hose sizing because it affects the flow velocity of the fluid within the hose. A hose with an oversized I.D. will result in sluggish system performance, while an undersized I.D. can cause excessive pressure drops, leaks, and system damage. Hose and fitting sizes are designated using dash numbers or dash sizes. The dash number designates the size in sixteenths of an inch (i.e. -03 is 3/16"), except for SAE 100R5 transportation and refrigerant hose. The chart below provides a reference for dash numbers and their corresponding hose sizes in inches.
