How is the vacuum reading on the compound/intake gauge measured?

The correct measurement of vacuum reading on the compound/intake gauge is done using mercury in inches of lift. This method relies on the principle that a column of mercury can be used to measure differences in pressure. When a vacuum is created, it reduces the atmospheric pressure in the intake line, causing the mercury to rise in the gauge. The height of the mercury column indicates the level of vacuum, usually measured in inches. This measurement is significant because it allows operators to assess how effectively the pump can draw water from a source.

Utilizing mercury in this way is a standard practice in vacuum measurement due to its density and specific properties, which provide a reliable indication of pressure changes. This method is well-established in both industrial and scientific applications, making it the most accurate choice for vacuum readings on compound/intake gauges.