Shaft resistance: The effects of the cages

Baird, G (1963) Shaft resistance: The effects of the cages. MSc(R) thesis, University of Glasgow.

Abstract

A critical review of the literature is made in which attention is foot on the efforts of previous workers to produce theoretical analyses of cage related problems. Their results are briefly discussed. The model shaft and one stationary cage tests are than described. The accuracy of the airflow measurements was ascertained end the validity of using the Pressure Drop Coefficient (P.D.C.) was chocked. Interference effects between the cage and buntons had a profound influence on the vane of the cage P.D.C., this effect varying for different types of bunton arrangement. It was shown aloe, that the cage P.D.C. may be assumed constant) whatever its position in the (unlined) duct. In Section 41 the Pressure Drop Theory of Dr. Rynear in conjunction with whoa some of this work was carried out) is presented. Formulae are proposed which define the P.D.C. of both single cage and two cages in the side-by-side position at their passing place in the shaft. Both stationary and moving cages are considered. These equations defining the P.D.C.'s for stationary cages were verified using the results of three previous workers and a correlation coefficient of 0.94 was obtained for the 2 types of model cage considered. Section 50 after a description of the pressure recording equipment, deals with some model teats on moving cages. Recordings wore made which showed the effect of the bunton spacing on a test length pressure drop with a cage moving in it. Those indicated that the effect on the accuracy of the recording diminished in the cage speed to air velocity ratio increased. The reduction in airflow as the cages passed was shown to be more accurately detectable by moans of a centrally positioned pitot-static tube than by the flomoter itself, whose readings fluctuated greatly. An attempt was also made to evaluate the theoretically predicted increase in P.D.C. of the two cage passing, when they were in the side-by-side position, compared with the stationary value, but no detectable difference could be found for the range of cage speeds available. Finally, the influence of the direction of the cage movement relative to the airflow, on the vane of the cage P.D.C. was illustrated. Some measure of success was achieved in correlating some moving cage test results with the theoretical cage P.D.C. values predicted from the Pressure Drop Theory. In the last part of this work, an attempt he been made to predict certain conditions which might arise in the upper horizon of t two horizon mine min ingle cage winding in one of its shafts. An equation to put forward which defines, for time steady conditions, the circumstances necessary for stopping the airflow in the upper level in terms of the circuit resistances and the cage and fan pressure characteristics.

• Item Type: Thesis (MSc(R))
• Qualification Level: Masters
• Additional Information: Adviser: G Hibbard
• Keywords: Mining engineering
• Date of Award: 1963
• Depositing User: Enlighten Team
• Unique ID: glathesis:1963-73181
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 14 Jun 2019 08:56
• Last Modified: 14 Jun 2019 08:56
• URI: https://theses.gla.ac.uk/id/eprint/73181