What is the curvature of the curve, the curvature of the plane curve is aimed at a point on the curve tangent Angle for arc length of rotation rate, defined by differential, shows that the degree of curve deviates from the straight line.
K = lim | Δ alpha/Δ s | Δ s tends to zero, curvature K is defined
Pipe radius of curvature, the reciprocal of curvature is the curvature radius. Somewhere on the radius of curvature is mainly used to describe the curve curvature change, special, such as: a round in a circular arc curvature radius equals the radius of the circle, perhaps can understand like this: is that a curve of differential as far as possible, until the final approximation of a circular arc, the circular arc radius.
Elbow according to the radius of curvature to points, divided into long radius elbow and short radius elbow
1) radius of curvature of the short radius elbow to elbow is approximately equal to the pipe diameter and R = 1 d.
2) refers to the long radius elbow bend curvature radius is approximately equal to 1.5 times the pipe diameter, R = 1.5 D.
R as the radius of curvature, D bend diameter.
Stainless steel pipe/curvature radius of curvature, to bend the sample:
Elbow volume (the volume / 1000000 * material density values, is the weight, unit: kg/a)
1) torus volume formula = PI * r * r * 2 * PI * r r – ring body section radius r – ring into the center of the ring body body section center distance, the radius of curvature
2) hollow torus volume formula = (r * r – PI PI * * r ‘* r) * 2 * PI * r r’ – ring body section within a radius of 180 degrees, 90 degrees, 45 degrees Angle is equal to 1/2 respectively, 1/4, 1/8 hollow torus
= 3), 90 – degree bend volume formula (r * r – PI PI * * r ‘* r) / 4 * 2 * PI * r = 2 * (D/D / 2 – (D – 2 * S) / 2 * (D – 2 * S) / 2) / 2 * PI * PI * r = (D – S) PI / 2 * PI * * S * r, D – bend diameter in mm S – elbow wall thickness, unit mm r – bend section center to the torus center distance, the radius of curvature, in mm
Such as 159 * 4 not 304 stainless steel 304 degree Angle, diameter is 159 mm, wall thickness of 4 mm to check the standard GB/T12459, long radius elbows curvature radius of 229 mm, short radius elbows curvature radius of 152 mm, 304 stainless steel elbow material density value is 7.93 g/cm ^ 3 g/mm ^ 3 = 7.93/1000 = 7.93/1000 Kg/mm ^ 3
The weight of the 90 – degree Angle formula = (D – S) * S * R * PI / 2 * PI * 7.93/1000000 Kg
(1). 304 stainless steel material, the weight of 90 degrees of the long radius elbow = (159-4) * 4 * 229 * 3.14 * 3.14/2 * 7.93/1000000 = 5.55 Kg
(2). 304 stainless steel material, the weight of 90 degrees of short radius elbow = (159-4) * 4 * 152 * 3.14 * 3.14/2 * 7.93/1000000 = 3.69 Kg
Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)