Pneumatics Problems

7/27/2019 Pneumatics Problems

1/22

Bulacan State UniversityCollege of Engineering

City of Malolos, Bulacan

Electro - Pneumatics

Problems

Resurreccion, Matthew L.BSEE-4A

Engr. Dennis AguirreProfessor

Grade


2/22

Problem:

Loose product (e.g. grain) is to be loaded into a container. To open the hopper door a

container must first be present (checked by means of a limit switch) and either of the two (2)

push buttons actuated, the hopper door is to remain open for five (5) seconds only, before

closing again. The time cycle is to commence from when the cylinder starts to extend.

Design circuits to meet these requirements.


3/22

Pneumatic Circuit Diagram and Electrical Wiring Diagram


4/22

Problem:

Components are to be washed before assembly, they are placed into a container, which

is to be dipped in and out of the cleansing fluid. Once the START push button has been

actuated the cylinder is to continuously cycle, until such time that the STOP push button is

actuated (two (2) separate push buttons are required). The container must not meet the

cleansing fluid with a hard impact (Danger of Splashes).

When the stop push button is actuated, the cylinder must stop in the retracted

(container UP) position.



5/22



6/22

Problem:

In shipping department of a large company, parcels, which arrive on a roller conveyor,

are to be despatched to one of four different destinations. Each destination is fed by a separate

output roller conveyor. The selection of the outputs is achieved by means of two double acting

cylinders, mounted back to back. The extend and retract of each cylinder is determined by

means of four (4) separate push buttons, if the cylinders were designated A and B and the

push buttons were designated 1, 2, 3, and 4, the following conditions should apply:

Actuation of 1 will extend A and retract B (no matter what their previous positions). Actuation of 2 will extend A and retract B (no matter what their previous positions). Actuation of 3 will extend both A and B (no matter what their previous positions). Actuation of 4 will extend both A and B (no matter what their previous positions).



7/22



8/22

Problem:

Toys are to be heat sealed into blister packs, a double acting cylinder will clamp the

plastic blister to the card backing, while the heat sealing takes place. The cycle is started by

means of a push button, which this is actuated the cylinder is to extend, slowly, to its forward

end position, it will then remain in this position for a period of five (5) seconds, while the heat

sealing takes place. Once the five seconds has elapsed the cylinder is to retract, rapidly, to its

initial position.

Additional requirements:

The cylinder must retract, after the five seconds, even if the push button has been helddown.

For the sequence to start again, the cylinder must reach its fully retracted position andthe start button must be operated again (if the push button is held down, the cylinder

must retract fully and then stop, until the push button is released and then actuated

once again), thus ensealing only one cycle from one actuation of the push button.



9/22



10/22

Problem:

Packages arrive at a transfer station, upon actuating a package register, they are lifted

by cylinder A (lift cylinder), to a second level, when this level is reached, the package is pushed

onto the roller track by cylinder B (transfer cylinder). Once cylinder B has fully extended,

cylinder A will retract (lower), only after cylinder B retract.

A Motion STEP Diagram is shown, illustrating the sequence of movements.

Cylinder A remains retracted until the next package arrives, when it does the cycle will

be repeated.

Design circuits to meet these requirements, utilising double solenoid directional control

valves.


11/22



12/22

Problem:

The door on a cold room store (e.g. supermarket) is to remain closed (not locked) at all

times, other than when a person is passing through it. When the door is approached from the

either side there are two (2) push buttons on the wall, adjacent to the door, one marked

Open, the other marked Close (therefore four (4) push buttons in total). A person wishing to

enter or leave the cold room may open the door by actuating either of the Open push buttons,

once through the door they will then actuate the Close push button.

It should be noted that when the system is at rest (door closed) the cylinder is in an

extended condition.



13/22



14/22

Problem:

Products (e.g. parcels) are to be separated in a distribution warehouse, where the

incoming products arrive on one conveyor and are to be despatched to either of two output

conveyors. The required output conveyor is selected by a double acting cylinder, which in turn

is controlled by an operator. The operator has in front of him, two (2) push buttons (separate

units), when one push button is actuated the cylinder will extend and remain extended, even

when this push button is released. To retract the cylinder the other push button must be

actuated, again the cylinder will remain retracted, even when the push button is released, until

such time that the first (extend) push button is actuated again.

Design circuits to meet these requirements:

a). Utilizing double solenoid directional control valve.

b). Utilizing single solenoid directional control valve.


15/22


Double Solenoid Directional Control Valve


16/22

Single solenoid Directional Control Valve


17/22

Problem:

The casting approaching on the right hand roller conveyor are to be shifted to a

different level and also realigned.

Cylinder 1 (Z1) piston rod extends after being triggered by a pushbutton and the liftingplatform on its end lifts the workplace to the level of the second roller conveyor. The lifting

platform remains at this level until the piston rod of cylinder 2 (Z2) pushes the workplace off of

the lifting platform and onto the upper roller conveyor.

As soon as cylinder 2 piston rod has safely pushed the workplace off of the lifting

platform and onto the upper roller conveyor, cylinder 1 piston rod moves back downwards with

the lifting platform.

Cylinder 2 piston rod does not retract until cylinder 1 piston rod has returned to its

bottom end position. All cylinder motions are to be steplessly adjustable.

A position dependent sequential control is to be selected.

Please, first if all, draw the position sequence diagram and then the circuit diagram.

Additional stipulation:

Cylinder 1 piston rod must not extend until is certain that cylinder 2 piston rod is in its

rear end position.


18/22



19/22

Problem:

Plastic bags are to be heat sealed, the neck of the bags is placed within the jaw of the

heat sealer and the jaw is then closed down onto them while the heat sealing takes place. The

jaw of the sealer is operated by a double acting cylinder; this cylinder is in turn controlled by

means of a foot pedal. When the foot pedal is actuated the cylinder will extend and remain

extended until the pressure in the rear chamber of it is at the same level as the system

pressure. Once this pressure is achieved and sensed the cylinder will retract, to its initial

position.



20/22



21/22

Problem:

A work piece is to be firmly clamped while it is drilled, the clamp is to be operated by

means of a double acting cylinder. For the cylinder to extend the following conditions must be

met:

A work piece must be present in the fixture. Either of two (2) push buttons is to be actuated.

Once these conditions are met the cylinder will extend, slowly (speed is to be

adjustable).

For SAFETY reasons, during drilling it must not be possible to unclamp the component,

when the drill is return to its uppermost position the component may be unclamped, by the

actuation of a third push button. The unclamping speed is to be very fast.



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