The Four-cylinder Frick Compressor, with its advanced design, ment, and attractive maroon finish, is the last word in large refrigerating machines. View shows standard by-pass arrangement. Note capacity control, compact arrange- signed for regular ammonia work. Outline dimen- sions and other details are given on the last page of this bulletin. To meet special requirements, these machines can be furnished with one pair of cylinders made larger than the other two. Such an arrangement is useful for carrying loads at two separate levels. The larger cylinders can be designed to serve as boosters handling low-temperature gas, and discharging through inter-coolers to the smaller high-pressure cylinders, thus providing a vertical two-stage machine. Eight or ten such combina- tions are available. In use, the machines require the very mini- mum of attention, and will operate continuously for months without being stopped for adjustments. Built for the heaviest service, their smooth-run-ning qualities are apparent wherever these com- pressors have been installed. Both the general design and the perfection of details are based upon our experience since 1882 in building all types and sizes of commercial and industrial refrigerat- ing equipment.
<Callout type="important" title="Key Design Features">The crankcase is a heavy one-piece casting with ribs for reinforcement, four manholes on each side, and three saddles cast integral with the crankcase. The cylinders are made from special semi-steel alloy, mounted in pairs above the crankcase, and surrounded by water jackets to keep heads cool.</Callout>
The metal used in pouring the cylinder castings is a special semi-steel that has been developed after years of research and experience with many thousands of compressor frames. The mix is held under rigid scientific control by daily tests in the laboratory, the iron being maintained at just the right density, strength, and hardness to resist wear.
<Callout type="gear" title="Maintenance Tools">Regular maintenance includes checking oil levels via sight glasses, cleaning filters every 30 seconds, and inspecting crankshaft bearings for proper alignment.</Callout>
The discharge valves are mounted in the safety heads and are of the ring-plate type, developed especially for this service. The valves, constructed with light moving parts, are quiet, tight, and reliable.
<Callout type="risk" title="Safety Hazards">Ensure proper installation to prevent slugs of liquid ammonia from entering cylinders; use spring-loaded safety heads to lift in case of such an event.</Callout>
The pistons are made of semi-steel with ample babbitced thrust surfaces, accurately ground to size. Connecting rods are of drop-forged steel, H-section, and are made long to lessen side thrust on the pistons.
<Callout type="beginner" title="Understanding Capacity Control">Capacity control valves can be opened in steps to reduce compressor capacity by 12.5%, 75%, 62.5%, or 50% as needed for load changes.</Callout>
Key Takeaways
- The four-cylinder Frick compressor is designed to handle heavy-duty refrigeration tasks with minimal maintenance.
- Cylinders are made from special semi-steel alloy for durability and wear resistance.
- Capacity control valves allow precise adjustment of the machine's output in response to varying loads.
Practical Tips
- Regularly inspect oil levels using sight glasses to ensure proper lubrication.
- Use ring-plate discharge valves for quiet, reliable operation under high pressure conditions.
- Install safety heads with spring-loaded lift mechanisms to protect against liquid ammonia slugs entering cylinders.
Warnings & Risks
- Improper installation can lead to serious safety hazards such as damage from liquid ammonia slugs.
- Failure to maintain proper oil levels and cleanliness of filters can result in reduced efficiency or machine failure.
Modern Application
While the specific machinery described here is outdated, the principles of compressor design, capacity control, and maintenance remain relevant today. Understanding these historical techniques provides a foundation for modern refrigeration systems and emergency preparedness.
Frequently Asked Questions
Q: What are the key features of the crankcase in the four-cylinder Frick compressor?
The crankcase is made from heavy one-piece casting with ribs for reinforcement, four manholes on each side, and three saddles cast integral with the crankcase to support bearings.
Q: How does capacity control work in this compressor?
Capacity can be reduced by opening valves that allow gas to bypass back into the suction ports. This reduces capacity in steps of 12.5%, 75%, 62.5%, or 50% as needed for load changes.
Q: What safety measures are included in the design?
Spring-loaded safety heads lift if slugs of liquid ammonia enter cylinders, preventing damage to the compressor and ensuring safe operation.