With reference to accumulators in pneumatic control systems:
(a) state the TWO main purposes;(2)
(b) explain why EACH of the purposes stated in part (a) are required.(8)
Accumulator in pneumatic control systems
In pneumatic control systems, an accumulator is a pressure vessel that stores compressed air under pressure. It acts as a reservoir of energy that can be used to supplement the compressor output or provide power during brief periods when the compressor is offline.
1. Compressed Air Safety Accumulator – VAT Valve
2. The Role of Accumulators and Coolers in Hydraulic and Pneumatic Systems
Key Functions:
- Energy Storage:
- Peak Demand: Accumulators store compressed air during periods of low demand, which can then be released during periods of high demand, reducing the load on the compressor and preventing pressure drops in the system. 1. How do accumulators improve system performance? – Mobile Hydraulic Tips www.mobilehydraulictips.com
- Emergency Power: In case of a compressor failure or power outage, the stored air in the accumulator can provide a temporary supply to maintain critical pneumatic functions. 1. Compressed Air Controls supply air compressor accessories compressedaircontrols.co.nz
- Pulsation Dampening:
- Smooth Flow: Accumulators help to dampen pulsations in the compressed air supply, particularly those caused by reciprocating compressors. This smoother flow can improve the performance and longevity of pneumatic equipment. 1. The Importance of Air Receivers / Auxiliary Air Tanks – VMAC www.vmacair.com
- Leakage Compensation:
- Minor Leaks: Accumulators can compensate for minor leaks in the system by maintaining pressure, allowing the system to continue operating without immediate disruption.
- Shock Absorption:
- Sudden Pressure Surges: In systems where sudden changes in pressure or flow can occur, accumulators help absorb these shocks and protect sensitive components. 1. The Role of Accumulators and Coolers in Hydraulic and Pneumatic Systems mobilehydraulics.com.au
Construction:
- Pressure Vessel: The accumulator is typically a cylindrical or spherical steel tank designed to withstand high pressures.
- Separator: It has an internal separator, usually a diaphragm or piston, that separates the compressed air from a pre-charged gas (often nitrogen). 1. The Role of Accumulators and Coolers in Hydraulic and Pneumatic Systems mobilehydraulics.com.au
- Pre-charge Gas: The pre-charge gas provides the initial pressure in the accumulator and allows for the compression and expansion of the air volume.
Operation:
- Charging: When the compressor is running and the system pressure is high, compressed air enters the accumulator, compressing the pre-charge gas and storing energy.
- Discharging: When the system demand exceeds the compressor’s output or the compressor is offline, the compressed air in the accumulator expands, pushing against the separator and releasing stored energy into the system.
Benefits:
- Improved System Performance: Reduces pressure fluctuations, improves system responsiveness, and allows for smaller compressors.
- Increased Reliability: Provides backup air supply in case of compressor failure or power outages.
- Energy Savings: Helps reduce energy consumption by minimizing compressor cycling and allowing for more efficient compressor operation.
- Extended Equipment Lifespan: Dampens pulsations and absorbs shocks, reducing stress on pneumatic components and increasing their lifespan.
Typical Applications in Pneumatic Control Systems:
- Emergency Shutdown Systems: Ensures sufficient air pressure to activate critical safety systems in emergencies.
- Control Valves: Provides additional air volume for rapid actuation of large control valves.
- Pneumatic Tools: Buffers pressure fluctuations and ensures adequate air supply for pneumatic tools.
- Other Applications: Any system requiring a stable air supply, pulsation dampening, or emergency backup can benefit from an accumulator.
In summary, an accumulator in a pneumatic control system is a valuable asset for enhancing performance, reliability, and safety. It acts as a buffer, storing energy and smoothing out pressure fluctuations, ensuring that the system operates effectively even during peak demands or unexpected disruptions.
Purposes of accumulators in pneumatic control systems
Accumulators in pneumatic control systems serve several crucial purposes, contributing to their overall performance, efficiency, and reliability:
- Energy Storage and Supply:
- Peak Demand Management: Accumulators store compressed air during periods of low demand, releasing it during peak demand or when the compressor is temporarily unable to supply sufficient air. This helps maintain a consistent air pressure in the system, preventing pressure drops that could affect the operation of pneumatic equipment. 1. How do accumulators improve system performance? – Mobile Hydraulic Tips www.mobilehydraulictips.com
- Emergency Backup: In case of a compressor failure or power outage, the stored air in the accumulator can provide a temporary supply for critical control functions, allowing for a controlled shutdown or maintaining essential operations until the compressor is restored.
- Pulsation Dampening:
- Smooth Flow: Accumulators dampen pressure pulsations generated by reciprocating compressors or other sources of fluctuating flow. This smoother flow reduces stress on pneumatic components, improves control accuracy, and minimizes noise and vibration.
- Leakage Compensation:
- Maintaining Pressure: In systems with minor leaks, accumulators help maintain system pressure by compensating for the gradual loss of air. This allows the system to continue operating without immediate disruption while the leak is being addressed.
- Shock Absorption:
- Sudden Pressure Surges: Accumulators absorb sudden pressure spikes or surges that can occur in pneumatic systems, protecting sensitive components like valves, actuators, and instruments from damage.
- Auxiliary Power Source:
- Emergency Operations: Accumulators can provide a source of pressurized air for emergency operations like opening or closing valves, operating safety systems, or powering pneumatic tools when the main compressor is unavailable.
- Cost and Efficiency Optimization:
- Smaller Compressor: By providing a buffer for peak demand, accumulators allow the use of a smaller compressor, reducing initial investment and energy consumption.
- Reduced Compressor Cycling: Accumulators minimize the frequency of compressor starts and stops, reducing wear and tear on the compressor and improving its efficiency.
Specific Applications in Pneumatic Control Systems:
- Emergency Shutdown Systems: Ensuring sufficient air pressure to activate critical safety systems in emergencies.
- Control Valves: Providing additional air volume for rapid and smooth actuation of large control valves.
- Pneumatic Tools: Smoothing out pressure fluctuations and ensuring adequate air supply for consistent tool performance.
- Process Control: Maintaining stable pressure and flow for precise control in various industrial processes.
Overall, accumulators are essential components in many pneumatic control systems, contributing significantly to their performance, reliability, safety, and efficiency. They provide a buffer against pressure fluctuations, ensure a readily available air supply, and protect against system disruptions and damage.