Final answer:
Packing gland seals are used on large capacity ammonia compressors to prevent ammonia leaks.
Step-by-step explanation:
Packing gland seals are used on Large capacity ammonia compressors. These compressors handle the compression of large amounts of ammonia gas, which is used in various industrial processes. The packing gland seals help prevent ammonia leaks by creating a barrier between the rotating shaft and the stationary housing of the compressor.