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The theory of relaxation speed V-seal derivation of the lifting process of the erected mast and the simplification of the various dimensions as shown. Lifting masts Note: 1 - auxiliary mast cable rope; 2- auxiliary mast; 3-lift pulley group; 4-stand mast; 5--bottom pulley block. In the above, it is assumed that the line BO of the auxiliary mast's lifting lug B and the pivoting joint O of the standing mast is perpendicular to the ground, and the other geometrical dimensions are assumed as follows: (1) The height BO of the auxiliary mast lifting lug is H; (2) The distance CO from the main lifting point C of the stand mast to its swivel hinge O is L; (3) The distance AO of the tying point A to the swivel joint O is L1; (4) The swivel hinge of the stand mast The distance OP from the fixed point P of the bottom cover pulley group is L2; ​​(5) the moving speed of the lifting pulley of the lifting pulley group C is V; the two groups on both sides of the lifting pulley group are generally 15b. The movement of each pulley assembly moving pulley is generally 15b. The speed is V seal.
In the process of erecting the mast, the same angular rotation speed can be obtained at the same time A and C, and the conversion of the trigonometric function relationship can be obtained. VLSin(arctgHcosHL-HsinH)=2V seal cos15bL1sin(arctgL2sinHL1-L2cosH) can be obtained. : V seal = VL1sin (arctgHcosHL-HsinH) 2cos15bLsin (arctgL2sinHL1-L2cosH) The above formula is a function expression of the relaxation speed of the bottom cover pulley during the erection of the mast. It can be seen that it is a function of L1, L2, H, L, V, and H.
An example is the use of an auxiliary mast rotation method to erect a main mast in the alkylation unit of Yanhua Refining Division, and then hoisting other large equipment with the main mast. The basic parameters are as follows: (1) H = 48m; (2) L = 48m; (3) L1 (seat type) = 0.4m; (4) L2 = 14m; (5) moving speed of the moving pulley of the lifting pulley V =V pull / M. Lifting pulley The movable pulley is usually a labor-saving pulley block according to its working principle, and the free end of its flexible member is often connected to the winding of the hoist through the guiding pulley. The traction speed of the free end of the flexure is V, and the magnification of the pulley block is M.
V pull-check 5 mechanical equipment installation manual 6P125-65 select 10 tons of winch, its average rope speed V pull = 6.5m / min; M lifting pulley, select H100889 double tap, M = 8. Replace the above data into V seal In the functional relationship, it can be obtained that: V seal = 01325sin (arctgcosH1-sinH96cos15bsin(arctg14sinH014-14cosH)) When the rotation angle H of the to-be-positioned mast changes from 0b90b, the corresponding value of the V-sealing is made by the HV method. Curve change relationship as shown in the analysis and conclusion (1) Relaxation speed V seal is derived under specific circumstances. It is a function of L1, L2, H, L, V and H.
(2) When L1, L2, H, L, and V are regarded as constants, the HV seal curve change relationship is made. (3) It can be clearly seen from the curve change relationship that the relaxation speed V seal is from fast to slow and becomes a downward trend. When the H angle is at 0b10b, the V seal changes rapidly; when the H angle is at 10b20b, the V seal changes faster; when the H angle is at 20b40b, the V seal changes slowly; when the H angle is above 40b, the V seal The change is more gradual. This requires the operator to control the relaxation speed of the back cover pulley group by observing the angle indicator at the lower part of the mast after accurately grasping the curve change relationship.
HV seal change curve (4) The speed V of the lifting pulley block movement is not a constant, but a variable. It increases as the number of ropes wound into the hoist increases. To simplify the calculation, the average speed of the entire lifting process is taken here. (5) In the functional relationship of the V seal, L1 is the projection of the distance from the lashing point to the swivel hinge on the center line of the mast. L1 is different depending on the structure of the bottom of the mast.