A Pneumatic System Requires An Average Delivery Volume Of 15 ✓ Solved

A Pneumatic System Requires Ll Ayerage Delivery Votume Of 15m3mi

A pneumatic system requires an average delivery volume of 15m³/min free air. The compressor is rated to supply 30m³/min FAD and a working gauge pressure of 6.5 bar. Determine the minimum size of compressor receiver if there is an allowable 15 starts per hour.

A double acting pneumatic cylinder is to be used to clamp work in a fixture. The required clamping force is 5kN and system gauge pressure is 5 bar. Taking frictional losses to be 5%, calculate the minimum cylinder diameter which could be used in this application.

Loose powder is to be loaded from a hopper into a container. To open the hopper door a container must first be present (checked by a limit switch) and either one of two pushbuttons must be actuated. The hopper door should then remain open for five (5) seconds only. Draw a pneumatic circuit that is able to meet these requirements.

Produce a hydraulic circuit diagram for a system that could operate a door requiring a closing force of 1 tonne and would close the door in 10 seconds. You should include a short description and include calculations to show evidence that you have chosen an appropriate flowrate pump to match the actuator. No system pressure is given, so you should choose a pressure to use in your calculations (between 50 bar and 150 bar).

Paper For Above Instructions

In this paper, we will explore the requirements and calculations necessary for designing pneumatic and hydraulic systems as per the outlined specifications. The requirements include determining the optimal size of a compressor receiver, calculating the appropriate cylinder diameter for a double-acting cylinder, drawing a pneumatic circuit for loading loose powders, and producing a hydraulic circuit diagram for door operation.

1. Compressor Receiver Size Calculation

To determine the minimum size of the compressor receiver, we must consider the compressor's free air delivery and the operational characteristics. The compressor has a capacity of 30m³/min at a pressure of 6.5 bar, while the pneumatic system requires a continuous delivery of 15m³/min.

The difference in delivery indicates that the compressor has sufficient capacity to meet the pneumatic system's demands. To ensure proper operation with an allowable maximum of 15 starts per hour, we can calculate the required compressed air reservoir volume using the formula:

V = (Q × t) / P,

where V is the volume of air stored (m³), Q is the delivery rate (m³/min), t is the time (min), and P is the pressure (bar).

Assuming the compressor cycles every four minutes (15 starts per hour equals 4 minutes per start), the volume of the receiver becomes:

V = (15 m³/min × 4 min) / 6.5 bar = 0.923 m³ or 923 liters.

Thus, the minimum size of the compressor receiver required is approximately 923 liters.

2. Cylinder Diameter Calculation

The clamping force (F) required for the double-acting pneumatic cylinder is given as 5 kN, and the gauge pressure (P) is 5 bar. Considering frictional losses of 5%, the effective pressure (Pe) can be calculated as:

Pe = P × (1 - friction losses) = 5 bar × (1 - 0.05) = 4.75 bar.

We convert the effective pressure from bar to pascal:

Pe = 4.75 bar × 100,000 = 475,000 Pa.

The area (A) required to generate the clamping force can be calculated using the formula:

F = Pe × A

Hence, rearranging gives:

A = F / Pe = 5,000 N / 475,000 Pa ≈ 0.010526 m².

To find the diameter (D) of the cylinder, use the formula for the area of a circle:

A = (π/4) × D².

Solving for D gives:

D² = (4 × A) / π = (4 × 0.010526) / 3.14 ≈ 0.01343 m²;

D ≈ √0.01343 m² ≈ 0.1158 m, or approximately 115.8 mm.

The minimum cylinder diameter for this application is 116 mm.

3. Pneumatic Circuit Diagram for Loading Loose Powder

For the pneumatic circuit that allows loose powder to be loaded from the hopper into a container, the steps involved include:

1. A limit switch that checks for the presence of the container.
2. Activation of one of two pushbuttons to trigger the opening of the hopper door.
3. A timing mechanism that keeps the door open for 5 seconds before closing.

The pneumatic circuit will consist of:

• A compressor connected to the pneumatic cylinder for door operation.
• A limit switch connected in series with the pushbuttons.
• A timer relay that controls the duration of the door opening.

The output will ensure that the hopper door opens only when a container is detected and remains open for the specified duration, allowing for effective loading.

4. Hydraulic Circuit Diagram for Door Operation

For the hydraulic circuit to operate a door requiring a closing force of 1 tonne and close within 10 seconds, the process involves selecting a pressure. We will select a pressure of 100 bar for these calculations:

The required flowrate can be estimated with the flow rate formula:

Q = A × v = (1,000 kg × 9.81 m/s²) / (100,000 Pa) ≈ 0.0981 m³.

Assuming we want the actuator to move within 10 seconds:

Flow rate = 0.0981 m³ / 10 s = 0.00981 m³/s or 9.81 L/s, which helps decide the pump specifications.

The hydraulic circuit will consist of a hydraulic pump, valve configuration, and the actuator designed to match the necessary flow rate and pressure for effective door operation.

Conclusion

In conclusion, the design and calculation of pneumatic and hydraulic systems require careful consideration of the various parameters involved to ensure effectiveness and efficiency. The compressor receiver size, cylinder diameter, pneumatic circuits for loading, and hydraulic systems for door operation must all be accurately determined for optimal performance.

References

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