Introduction to Pedal Pedal and Pneumatic actuator Operated Air Compressor
In previous posts ,I have tried to explain the some interesting Pedal operated mechanical projects. This project is actually mini project suitable for diploma (less certain about degree project-need to do modification). Pedal power can be used to get compressed air within minimum cost. This is small capacity compressor can be design upto 5 kg/cm2 gauge pressure reading. Pneumatic actuator is used in this project to compress the air . Actually, actuator do not compress the air ,it just force the air into the tank and air starts to pressurise in tank itself when volume of air get reduced because more and more air is admitted in the tank. This air is not allow to flow back because of check valve. Detailed list of compounds are explained below.
Components requirement and their Design Guideline:
1. Bicycle Model:
Proper and comfortable seating arrangement must be design so it will produce less Operator Fatigue. Seat height is selected according to Ergonomics principles and Using anthropometric data. Other Dimensions of Frame should be selected by considering same effect. Handles should be there for proper pulling force or griping purpose. Simple pipes can be welded together to form a Frame with Seating and Stand arrangement.
2. Connecting Rod:
It is a simple rod which connect the Crank i.e. pedal shaft and Pneumatic actuator piston rod . The connection mechanism shown in figure. One end of rod is connected to pedal by using any scrap round part for exa.-Bearing recess. Pneumatic actuator piston rod is connected by welding to other end of rod.
Fig. Connection mechanism for pedal and Rod
3) Air Storage Tank:
Tank is required to store the compressed air, actually air starts compressing in tank itself. So tank must be designed by following Design Of Pressure Vessel Standards e.g. ASME standards available for boiler and Pressure Vessel.
Refer Article : Design Of Simple Pressure Vessel -Its parts, Classification
4) Pneumatic actuator :
Actuators are basically used to convert hydraulic or pneumatic energy into useful mechanical movement i.e. either reciprocating movement or rotating movement. Actuators are the last part of any hydraulic or pneumatic circuits. There are various types of actuators -mainly two types- reciprocating actuator (used in application like automatic clamping, shaper machine circuit, lifting mechanism, cranes, JCB Vehicles ) and second one is rotary actuators (used in application like Drilling, driving the spindle of the machine etc.) available in the market , according to application and requirement specific actuator can be chosen. Here, we need a a cylinder assembly which consists of parts like piston, piston rods, tie rods, various seals, Inlet and outlet ports. Double actuated piston cylinder assembly is necessary for this project.
5) Non return valve (Check valve) and shuttle valve :
Check valve is a 'One way valve'
Check valve allows fluid flow only in one direction, back flow is restricted because of check valve ball and spring arrangement . figure shown the location and working of check valve. Shuttle valve is just ON-OFF controller which useful to regulate the amount of compressed pressurised air.
6) Pressure Gauge :
Small Pressure gauge must be fitted on the pressure vessel or tank for safety purpose and to measure actual performance of the project.
Working Of the Project :
1) Slotted rod is connected in between pedal and piston rod, Slot Guide allows movement of Slotted rod in fix path.
2) piston assembly need to buy from market ,this one comes in standard specification. (If you want guidance regarding piston specification then comment below ). piston assembly one end is fitted to the fulcrum, due to this piston assembly keeps oscillating but seriously it won't affect much on performance of the project.
3) When pedal rotate, rod get actuated and 'to and pro' motion of piston rod is achieved. This causes suction of air and this air is passed via pipes and check valve to the tank and pressure building in tank may get started.
• Power saving as it is manually operated
• Easy mechanism and simple construction
• As it is pedal operated so good for health
• Comfortable then ordinary hacksaw