self-elastic stacked capsule movement
beryllium, cardboard, copper, glass, mercury, plastic, steel
This Soviet Aneroid Barometer BAMM-1, dated 1972, was manufactured by the renowned Moscow instrument-making plant Hydrometpribor. Its operating principle is based on the well-known property of diaphragm aneroid capsules to deform in response to changes in atmospheric pressure. The linear displacement of the capsules is transmitted through a system of levers and converted into the angular movement of the indicating pointer across the scale.
The barometer is housed in a strict cylindrical case, characteristic of Soviet measuring instruments of the mid-20th century. The case is made of black moulded plastic with a matte surface and a subtle satin sheen, resistant to mechanical impact and temperature fluctuations. A distinctive feature of the construction is the screw-on, knurled plastic bezel—a solution rather uncommon for aneroid barometers—which provides secure retention of the glass and facilitates servicing. The bezel holds a flat mineral glass, recessed flush with the front surface, protecting the dial from dust and accidental contact.
The dial is made of dense cardboard mounted on a rigid backing. Its surface has an even, slightly warm light tone, typical of Soviet graphic printing of the 1950s. The barometric scale is applied by offset printing and arranged as concentric graduations calibrated in centimetres of mercury over a range of 60–80 cm Hg. The clear typography and uniform spacing emphasize the instrument’s functional character and its focus on precise measurement.
In the lower portion of the dial there is an arcuate cut-out, behind which an integrated mercury thermometer is positioned. The thermometer is calibrated in degrees Celsius from −10 to +40 °C, allowing the user to monitor ambient temperature simultaneously and to take into account its influence on pressure readings. The glass bulb of the thermometer is neatly integrated into the dial layout and visually balances the scale—forming, almost playfully, a subtle “smiling” motif.
The instrument is supplied with a protective polystyrene case, precisely shaped to match the body of the barometer and ensuring secure fixation during storage and transport. The lid of the case bears a relief-moulded inscription “BAMM” (rendered “БАММ” in Cyrillic)—a concise marking that both identifies the model and serves as a visual element of the packaging. The foam case reflects the pragmatic approach of Soviet instrument design, in which protection and preservation of the measuring device were considered integral parts of the product.
At the heart of the instrument lies a classic Soviet aneroid mechanism. Atmospheric pressure acts upon a stack of three self-elastic corrugated aneroid capsules, each approximately 65 mm in diameter. The motion of the capsule stack is transmitted via a central stem, then through a lever, a rocker arm, and a linkage connected to the pointer shaft by means of a very short fusee chain.
The self-elastic aneroid capsules used in Soviet barometers of the late 20th century were predominantly manufactured from beryllium bronze, a material valued for its high elasticity, non-magnetic properties, and long-term stability. These characteristics made it possible to dispense with external return springs and significantly improve the long-term accuracy of the instrument.
The entire barometer mechanism is mounted between two steel plates. One end of the capsule assembly is fixed, while the other is hinge-connected to a rigid linkage whose opposite end is articulated to the fork of an adjustable regulator mounted on an intermediate shaft. By increasing or decreasing the effective arm of the regulator using the adjustment screw, the sensitivity of the barometer can be correspondingly reduced or increased. Clearances in all moving joints of the mechanism are eliminated by a spiral spring.
When atmospheric pressure increases, the aneroid capsule stack compresses and rotates the intermediate shaft in such a way that the fusee chain is tensioned, causing the roller to rotate. When atmospheric pressure decreases, the capsule stack expands; as the intermediate shaft turns, the tension of the fusee chain is reduced, and the spiral spring—seeking to eliminate the resulting backlash—rotates the pointer shaft accordingly. The aneroid mechanism is installed within a case that features a lateral access opening, through which a screwdriver can be used to turn the adjustment screw for setting the barometer pointer to the scale division corresponding to the actual atmospheric pressure during calibration.
The convenient modular construction provides exceptionally easy access to the movement: it is sufficient to unscrew the bezel, remove the glass, and lift out the entire internal assembly from behind the dial, which is held in place without any additional fasteners.
The BAMM-1 aneroid barometer represents a striking example of Soviet engineering design of the 1950s, in which functional austerity is combined with thoughtful construction and careful graphic execution. The instrument clearly embodies the ethos of its era: reliability, clarity of readings, and an orientation toward long-term use in both professional and educational environments.