MET230 Week 2 - Hydraulics and Pneumatics

Engineering - Electronic Engineering Review Assignment Hydraulic Motors and Circuits

MET230: Hydraulics and Pneumatics

Week 2 Review Assignment

Problem 1

A rotary actuator has the following physical data:

Outer radius of rotor = 0.75 in

Outer radius of vane = 1.5 in

Width of vane = 0.75 in

If the torque load is 1000 in?lb, what pressure must be developed to overcome the load?

Problem 2

A hydraulic motor has 7.5-in3 volumetric displacement. If it has a pressure rating of 1200 psi and receives oil from a 25-gpm theoretical flow-rate pump, find the motor

a. Speed

b. Theoretical torque

c. Theoretical horsepower

Problem 3

A hydraulic motor has a displacement of 165 cm3 and operates with a pressure of 98 bars and a speed of 1725 rpm. If the actual flow rate consumed by the motor is 0.0055 m3/s and the actual torque delivered by the motor is 210 N?m, find

a. ηv

b. ηm

c. ηo

d. kW power delivered by the motor

Problem 4

A hydraulic transmission operating at 110-bars pressure has the following characteristics

__________________________________________

Pump motor____

VD = 65 cm3 VD = ?

ηv = 86% ηv = 93%

ηm = 92% ηm = 89%

N = 1740 rpm N = 550 rpm__

Find the

a. Displacement of the motor

b. Motor output torque

Problem 5

A pressure relief valve has a pressure setting of 850 psi. Compute the horsepower loss across this valve if it returns all the flow back to the tank from a 180-gpm pump. An unloading valve is used instead to unload the pump. If the pump discharge pressure during unloading equals 50 psi, how much hydraulic horsepower is being wasted?

Problem 6

The system shown below has a hydraulic cylinder with a suspended load W. The cylinder piston and the rod diameters are 2.5 in and 0.25 in respectively. The pressure relief valve setting is 1600 psi. Determine pressure p2 for a constant cylinder speed if

a. W = 575 lb

b. W = 0 (load is removed)

Figure for Problem 6

Problem 7

A double-acting cylinder is hooked up in the regenerative circuit shown. The relief valve setting is 110 bars. The piston area is 300 cm2 and the rod area is 65 cm2. If the pump flow is 0.0085 m3/s, find the cylinder speed and load-carrying capacity for the

a. Extending stroke

b. Retracting stroke

Problem 8

For the system shown (for the extension strokes of the cylinders), what pump pressure is required if the cylinder loads are 12000 lb each and cylinder 1 has a piston diameter of 6in?

Problem 9

a. Calculate the required size of a receiver that must supply air to a pneumatic system consuming 25 scfm for 12 min between 180 psi and 155 psi before the compressor resumes operation.

b. What size is required if the compressor is running and delivering air at 12 scfm?

Problem 10

Air at 110oF passes through a -in-diameter orifice having a flow capacity constant of 3.5. If the upstream pressure is 1500 psi, what is the maximum flow rate in units of scfm of air?

 

 

 

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