Development of single screw compressor technologies and their tendency

Single screw compressor (SSC), a strong competitor of the twin screw compressor, is regarded as an excellent gas compressor because of symmetrical structure and balanced gas forces on the screw rotor. However, the market for the SSC is tiny compared with that for the twin screw compressor because of the serious abrasion of star-wheel teeth. In recent years, this problem has been solved due to the development of the new profiles of meshing pairs, and the SSC has attracted more attention due to its high application potential for low-temperature heat pump, mechanical vapor recompression, and two-phase expansion. Nevertheless, there are still many technical problems remained to be solved for applying SSC to these fields urgently. In this paper, a comprehensive review on the progress and development of SSC technologies is presented. The review first combs the current situation of SSC products. Besides, the design and processing of meshing pairs are clarified and analyzed. Moreover, the working process of SSC and its performance in new applications are discussed in detail. Finally, the further research direction of the SSC is also discussed, which will be beneficial for designing high-efficiency SSC.

Method for effective monitoring and control of the positioning of the output link of the mechatronic module

This article is devoted to the problem of linear positioning of the output link of a mechatronic module (MM), made on the basis of a ball screw (ball screw). The analysis of typical schemes for constructing an MM controller using signals from radial position sensors of the ball screw rotor and a discrete indicator of the linear position of the output link in the working stroke section with the possibility of implementing an emergency (emergency) power off of the entire positioning system in the event of the output link extending beyond the working stroke. An optimal technical solution is proposed for constructing a linear positioning sensor of the output link based on combining the functions of the “referent points” indicator and the “limit switch” MM. Тhe cost-effectiveness of the new

Inter-lobe clearance estimation for twin-screw rotor pairs with point-meshing features

In practical production, it is impossible even to measure the inter-lobe (meshing) clearance of a screw rotor pair. However, understanding of the clearance distribution is essential since it is a major leakage path which greatly affects the twin-screw pump performance. Previous publications did not disclose explicit detail on how to calculate the meshing clearance for screw rotor pairs with point-meshing features. Therefore, this study proposes a meshing clearance calculation method for screw rotor pairs with point-meshing features. The complex meshing clearance can be simply determined by calculating the shortest distance between two normal-rack profiles generated using point-enveloping principle. Clearance distributions are much more intelligible to be exhibited on a 3-D contact line and the rotor profile. Due to its immeasurability in practice, the adaptability and the solution accuracy of the proposed numerical method are verified by applications on different rotor profiles and comparisons with measured results from a 3-D CAD model. The meshing clearance in a variable-pitch screw rotor pair and the clearance adjustability are also illustrated through the proposed examples.