320 likes | 608 Views
Hydraulic cylinders. Cylinder types: piston, double acting. x. Valves. Symbol. Pressure relief valve. A. C. k. F spring. p sys. Q p. Pressure relief valve. Curtain surface: Circumference ∙ height = k ∙ x = A c. Force equilibrium:. Theoretical basics. (1). Bernoulli equation:.
E N D
Hydraulic cylinders Cylinder types: piston, double acting Hydraulic and Pneumatic Systems
x Valves Symbol Pressure relief valve A C k Fspring psys Qp Hydraulic and Pneumatic Systems
Pressure relief valve Curtain surface: Circumference ∙ height = k ∙ x = Ac Force equilibrium: Theoretical basics (1) Bernoulli equation: (2) (3) Qrv depends nonlinearly on x or if we express x from (1) then: (4) Hydraulic and Pneumatic Systems
Pressure relief valve Let be the pressure when the valve just opens (x = 0) Theoretical basics: subst. to (4) (5) (5) is valid from x = 0 to x = xmax, xmax being the displacement when the spring is completely compressed If p > pmax : Hydraulic and Pneumatic Systems
Qrv psys pmax negative part: physically impossible belongs to xmax Pressure relief valve Theoretical basics: Hydraulic and Pneumatic Systems