scholarly journals CALCULATUION OF DYNAMIC PARAMETERS OF REVERSE CHAMBER OF PNEUMATIC HAMMER WITH MECHANICAL LOCKING OF ELASTIC VALVE

2019 ◽  
Vol 2 (5) ◽  
pp. 98-102
Author(s):  
Alexander Chervov

In paper short description of construction and functioning of pneumatic hammer with air distribution system based on application of elastic valve in exhaust line of reverse chamber is carried out. Using specified parameters of pneumatic hammer (percussion energy, percussion speed, ration of chamber squares, form of working chamber, compressed air pressure and etc.) mass of striking pin, working path, diameters of working chamber and cylindrical part of reverse chamber, dimensions of circle elastic valve are calculated. Proposed method of calculation considers change of cross-section of reverse chamber when striking pin moves back. Obtained calculated values have allowed to develop diagram chart of change of air pressure in reverse chamber in dependence on time.

2021 ◽  
Vol 2 (4) ◽  
pp. 78-86
Author(s):  
Alexander Yu. Primychkin

The paper considers one of the promising shut-off and control elements of the air distribution system of pneumatic impact machines - an annular elastic valve (CUV). This element allows you to reduce the energy consumption of pneumatic devices. Unfavorable combinations of factors that hinder the movement of the valve necessary for sealing the working chamber are considered. The paper presents a method for calculating the elastic valve that controls the release of energy from the return chamber of the pneumatic impact machine, which allows determining the main geometric dimensions of the valve device at the design stage, which provides a stable self-oscillating cycle of the pneumatic impact machine with the specified energy characteristics. The developed technique was used in the modernization of the air distribution system of the ring impact machine (KUM), designed for immersion of rod elements in the ground. Tests of the resulting sample in production conditions confirmed the increase in energy performance compared to previously produced machines of a similar type.


2020 ◽  
Vol 2 ◽  
pp. 219-225
Author(s):  
Vladimir V. Chervov

A brief description of the equipment used for trenchless pipe laying is given. The basic parameters of a pneumatic hammer designed for driving pipes into soil with an open end greater than 426 mm in diameter are substantiated. The description of the device and operating principle of a pneumatic hammer with an air distribution system using an elastic circular valve as the main element is presented. Based on the analysis of many-year operation of equipment for trenchless pipe laying and driving vertical pipes, the frequency and sequence of crack appearance, destruction and failure of the main parts of the pneumatic hammer are determined. New principles of calculation and design of a pneumatic hammer with a large mass of the striking part without loss of work performance are proposed. The solution to the problems associated with fatigue failure of the main parts is a decrease in striking velocity.


2007 ◽  
Vol 11 (4) ◽  
pp. 79-94 ◽  
Author(s):  
Brajesh Tripathi ◽  
Moulic Sandipan ◽  
Late Arora

Comfort conditions in air-conditioned rooms require that temperature in the occupied zone should not vary by more than 1?C and velocity, every where in the room, should be less than 0.15 m/s so that occupants do not feel draft. Recent developments in providing effective insulation and making leak tight buildings are considerably reduced the cooling load requirements and the supply airflow rates. Obtaining uniform temperature distribution with reduced air volume flow rates requires careful design of air distribution system. This study aims to find velocity and temperature distribution in the room towards this end.


Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8130
Author(s):  
Ziwen Dong ◽  
Liting Zhang ◽  
Yongwen Yang ◽  
Qifen Li ◽  
Hao Huang

Stratified air distribution systems are commonly used in large space buildings. The research on the airflow organization of stratified air conditioners is deficient in terms of the analysis of multivariable factors. Moreover, studies on the coupled operation of stratified air conditioners and natural ventilation are few. In this paper, taking a Shanghai Airport Terminal departure hall for the study, air distribution and thermal comfort of the cross-section at a height of 1.6 m are simulated and compared under different working conditions, and the effect of natural ventilation coupling operation is studied. The results show that the air distribution is the most uniform and the thermal comfort is the best (predicted mean vote is 0.428, predicted percentage of dissatisfaction is 15.2%) when the working conditions are 5.9% air supply speed, 11 °C cooling temperature difference and 0° air supply angle. With the coupled operation of natural ventilation, the thermal comfort can be improved from Grade II to Grade I.


Engineering ◽  
2011 ◽  
Vol 03 (04) ◽  
pp. 384-388 ◽  
Author(s):  
Xin Wang ◽  
Chen Huang ◽  
Weiwu Cao ◽  
Xuelei Gao ◽  
Wen Liu

2020 ◽  
pp. 74-77
Author(s):  
Mikhail Gennadievich Zagoruyko ◽  
Sergey Anatolyevich Pavlov

The grain masses of the first and subsequent batches, the equivalent coefficient of the dead gap of the air distribution system are calculated, the expressions for calculating the air flow for these batches and the experimental data on the change in moisture and temperature of the grain over time are given.


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