Page 3
ρ
m
: Mass density, ρ value of stainless steel =7.93x10³kg/m
3
, ρ value of carbon steel =7.8x10
3
kg/m
3
, ρ value of
Aluminum =2.7 x10³kg/m
3
So: effective area at zero pressure (m²) @ t=20
℃
Po: This is pressure value when piston module doesn’t be deformed, can be instead by P, (MPa)
α
p
: thermal expansion coefficient piston, the typical value is 4.5×10
-6
℃
-1
α
c
: thermal expansion coefficient cylinder, the typical value is 4.5×10
-6
℃
-1
T: The temperature of piston (
℃
)
λ: pressure distortion coefficient cylinder (MPa-¹), Example: the piston and cylinder is tungsten carbide
material, cylinder outside diameter is 22 mm, cylinder height is 30 mm, piston length is 38 mm, the λ value as
below:
Part Number
Pressure Range
Piston Diameter Piston Area λ value of tungsten carbide
KY0.6
(0.04~0.6)MPa
11.28 mm
1 cm
2
Negligible
KY1
(0.04~1)MPa
11.28 mm
1 cm
2
Negligible
KY6
(0.1~6)MPa
5.046 mm
0.2 cm
2
Negligible
KY25
(0.5~25)MPa
3.568 mm
0.1 cm
2
7.413 ×10
-7
MPa-¹
KY60
(1~60)MPa
2.523 mm
0.05 cm
2
7.413 ×10
-7
MPa-¹
KY70
(1~70)MPa
2.523 mm
0.05 cm
2
7.196 ×10
-7
MPa-¹
KY100
(1~100)MPa
2.523 mm
0.05 cm
2
7.196 ×10
-7
MPa-¹
1.5 Piston cylinder assembly