This gauge should be watched for a period of time to determine the high and low pressures routinely attained. The variation in pressure will usually be small for modulated firing, but may be quite large for on-off operation of a boiler. This point will be discussed in a later issuance. The final step in inspection of the steam supply involves estimates of the purity of the steam. Impurities in the steam supply are very undesirable for those canning operations wherein the live steam comes in contact with the food being processed, and somewhat less serious, may cause loss of brightness of the cans during retorting.
Many plants have a condensate-return system to return condensed steam for reuse in boilers.
Most small plants will not utilize such a system. Often a corrosion control chemical is used in a condensate return system. Maryland Avenue, Baltimore, Maryland 21218.