Pneumatic Systems Flashcards
7 cards from real ITMC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Pneumatic Systems flashcards as text
During preventive maintenance on a pneumatic system, the technician notices the lubricator oil level is not decreasing. The MOST likely cause is:
Answer: The flow rate is too low to create the pressure differential needed to draw oil
Lubricators are venturi-operated and require a minimum flow rate to create sufficient pressure differential to draw oil into the air stream.
What is 'water hammer' in a pneumatic distribution system and what causes it?
Answer: Pressure shock waves caused by sudden valve closure trapping liquid slugs
Water hammer occurs when accumulated liquid condensate is driven at high velocity into a closed valve, creating destructive pressure spikes.
Which ISO cleanliness class applies to instrument and control air requiring the highest quality?
Answer: ISO 8573-1 Class 1
ISO 8573-1 Class 1 specifies the strictest limits for particulates, water content, and oil content for critical instrument and control applications.
A regenerative desiccant dryer uses two towers alternating between drying and regeneration. Regeneration is accomplished by:
Answer: Purging the offline tower with a portion of dried air to drive off absorbed moisture
Heatless desiccant dryers direct a small fraction of dried compressed air through the offline tower to strip moisture from the desiccant beads and exhaust it to atmosphere.
A pneumatic system uses a pressure-compensated flow control valve. Compared to a standard flow control, what advantage does it provide?
Answer: It automatically adjusts for changes in supply pressure to maintain constant actuator speed
A pressure-compensated flow control maintains constant flow rate (and thus actuator speed) even when supply pressure or load pressure varies.
When sizing a compressor for a pneumatic system, the designer must account for which additional load factor beyond the total calculated SCFM demand?
Answer: A leakage allowance (typically 10–30% of demand) for system inefficiencies
Industry practice adds a 10–30% leakage and future-growth factor to calculated demand when selecting compressor capacity.
A technician is troubleshooting a pneumatic circuit where a cylinder extends but will not retract. The 4/2 solenoid valve shifts correctly on both signals. The MOST likely cause is:
Answer: A blocked or failed flow control on the retract exhaust path or a damaged rod-end port seal
If the valve shifts but the cylinder won't retract, a blocked exhaust path (clogged muffler or flow control), crushed tubing, or a failed rod-end seal preventing pressure buildup are the prime suspects.