Overcrowded cattle facilities are characterized by poor air quality. Keeping the humid air in the state of 'pure' is the process of partial or complete separation of unwanted substances from it. In general, this process involves local operations: filtering, absorbing undesired gas components and dusting. As an important link between energy and kinematical principles, the development of a water purification system requires water pressure measurement and control. Manometers, vacuum-meters and differential pressure gauges for measuring low pressure, overpressure and pressure differentials for gases up to 4000 mmHg are called micromanometers, micro-vacuum-meters and differential micromano-vacuum-meters, respectively. In the testing of qualitative and energy characteristics in the humid air purification system with water, in the open, semi-closed and closed system (from the point of disposal of water), special attention is given to the instruments with liquid, with precise pressure reading of 15-500 Pa. For this purpose, due to the need for parallel measurement at 2-32 measuring points, the original variants of instruments for partial and group use were constructed. Their construction, as well as some variants of air pressure measurements, are the goal of a condensed description in this paper. With vertical manometer it is possible to adjust the length of PVC pipes and their desired diameter. Thirty two two-pipe manometers can be divided into 64 independent measuring tubes, in combination with cylindrical vessels on the micromanometer platform. Each two-pipe manometer can be used to measure the differential pressure, with adequate additives in the form of a Pitot-Prandtl tube. In addition to measuring the lower pressure, as well as the pressure difference, in a slit micromanometer, it is possible to connect transparent PVC vessels of different diameters, to measure higher pressures with operating fluids of smaller densities.