It sounds like you’re describing a swell pressure test apparatus used in geotechnical engineering to measure the swelling pressure of expansive soils. This device determines the pressure exerted by a soil specimen when it swells upon water saturation, which is critical for designing foundations on expansive soils. Below is a concise explanation based on your description.

The apparatus is designed to measure the swelling pressure of soil specimens molded to a specific density and moisture content. When the specimen is soaked in water within a soaking tank, it tends to swell. The load required to restrain this swelling is transferred through a perforated swell plate and a load transfer bar to a proving ring, which measures the force. The proving ring is connected to a hand-operated load frame’s lead screw, allowing precise application and measurement of the restraining load.