Czeslaw Janusz Jermak

Air Gauge Characteristics Linearity Improvement

This paper discusses calibration uncertainty and linearity issues of the typical back-pressure air gauge. In this sort of air gauge, the correlation between the measured dimension represented by the slot width and the air pressure in the measuring chamber is used in a proportional range. However, when high linearity is required e.g., nonlinearity less than 1%, the measuring range should be shortened. In the proposed method, based on knowledge of the static characteristics of air gauges, the measuring range is kept unchanged but the nonlinearity is decreased. The static characteristics may be separated into two sections, each of them approximated with a different linear function. As a result, the nonlinearity is reduced from 5% down to 1% and even below.

Discussion on Flow-Through Phenomena in the Air Gauge Cascade

Abstract In the paper, the flow-through phenomena in the air gauge are under discussion form the thermodynamic and gasodynamic perspective. The main elements of the cascade are considered the inlet nozzle (restriction), measuring chamber and the measuring nozzle with the measuring slot (displacement between the nozzle head and measured surface). The purpose of the analysis was to point out the impact on the metrological characteristics of the air gauge. In particular, attention was paid to the airflow through the measuring slot. Here, the complex phenomena take place, among others the supersonic areas and a “bubble ring,” which cause discontinuity and hysteresis in the static characteristic. On the other hand, the air stream expansion after the restriction (inlet nozzle) is observed in the measuring chamber. The point of the above discussion was to work out some recommendation on the nozzles geometry and the localization of the back-pressure measuring point in the chamber.

Concept and Design of New Type Valve with Helix Type Spool

The paper presents the design of new kind of electrohydraulic valve with helix type rotary spool. First part, provides a literature overview concerning on the construction of the hydraulic valves. Then, Authors present a pair of spool works principle of a new type valve. Finally, basic equations describing the valve are formulated and its simulation model is implemented in MATLAB-Simulink environment. The valve flow characteristics are collected from the model.

Dynamics of the Non-Contact Roundness Measurement with Air Gages

Abstract The paper presents the results of investigations on the air gages dynamic characteristics in the measurement of the round profiles of motor cylinders. The principle of the measuring device is explained, and the analysis of the air gages dynamics is described. The results of dynamic calibration enabled to eliminate those configurations of air gages that may not meet the requirements of the measurement they were designed for. After the proper air gages were chosen, the entire system underwent the accuracy test and passed it successfully revealing the method accuracy better than 10% compared to the reference measurement.

Dynamics of a cascade pneumatic sensor for length measurements

The results of the investigation and theoretical analysis of the simple pneumatic sensors dynamics in conditions of the step-changed length of the detail are presented. The mathematical model taking into account actual losses of the flow and adiabatic changes of the air in the measuring chamber was worked out. For the sensors with inlet and measuring nozzles dw and dp from 1 to 2 mm and the volume of the measuring chamber Vk equals 4 cm3 the setting time t0,95 is 12 to 45 ms, that enables to apply these sensors in the preventive inspection systems.

Pneumatic sensor with oblique nozzle for length measurements: evaluation of metrological properties

Investigation results of the metrological properties of the pneumatic sensor with oblique nozzle used for length measuring, have been shown in the paper. Because of the bevelling the measuring nozzle metrological parameters (such as sensitivity and measuring range) of the sensor have been improved. The optimal value of beveling angle is (gamma) equals 32.5 degree(s).