Application of The New Shape Crushing Plate in Machine Crushing Processes

Crushing plate profile dimensions: t - pitch, distance between teeth, w - teeth height, a - crushing surface width, γ - teeth walls inclination angle, b - width of the bottom of teeth

The crushing process in the space of the jaw crusher a) compression in jaw crusher, b) elementary case of the crushing modeling – compressing the rock block between flat stamps

Local and global failure mechanism: a) Prandtl failure mechanism (Prandtl[33]), b) global failure mechanism (method of characteristics) for di/a = 12.22 and ρ = 15°, c) solution for the modified Coulomb condition, the method of characteristics grid for ρ = 10°, Sc/Sr = 5, d) determination of the upper limit: block compressed by flat stamps (modified condition)

Determining the optimal dimensions of a stamp width for different internal friction angles ρ using the method of characteristics and the linear Coulomb condition for the laboratory crusher

Failure mechanism for coaxially arranged stamps for various pitch length

Crushing of “Mucharz” sandstone by a group of four flat coaxially arranged stamps. Sample failure mechanisms for different t/h ratios: a) 0.08; b) 0.23; c) 0.38; d) 0.45; e) 0.72; f) 0.94

An example of the specimen prepared for laboratory tests

Scheme of the model jaw crusher: 1a, 1b – crushing plates, 2a – fixed jaw, 2b – moving jaw, 3a, 3b front end rear toggle, 4 – pitman, 5 – eccentric shaft, a, b – width and length of the inlet slot, I – force measurement system, II – moving jaw displacement measurement system

Diagram of crushing process – feed size, crusher’s working chamber, sample crushing plates, sample product fractions (fraction 8–16, 16–31.5, 31.5–63 mm)

Figure 12

Plates used in the laboratory tests: a) flat, b, c) triangular profile, d, e) variable pitch and height of the teeth, f) variable width and pitch of the teeth (Fig. 6)

Figure 13

Diagrams of force F in toggle plate as a function of time for the entire attempt: a) flat plates-set I, b) triangular profile plates and coaxial arrangement of teeth – set II, c) variable pitch, height and coaxial arrangement of teeth – set IV, d) variable width, pitch and coaxial set of teeth – set VI

The two exemplary operation cycles of sandstone crushing by flat plates a) force vs. displacement diagram b) force vs. time diagram

Scheme of measurement of the outlet slot er for different plate sets, s - moving jaw displacement (throw)

Crushing forces, crushing energy and technical performance

Crushing plates type	Maximum crushing force	Average maximum crushing force	Average crushing force	Specific energy	Technical performance

	F_peak	${\bar{F}}_{{av}_{max}}$ \bar F_{av_{\max } }	F_av	L_s	W_t

	[kN]	[kN]	[kN]	[kJ/kg]	[t/h]
I	262.80	138.76	45.72	3.07	2.13
II	234.39	64.84	16.69	3.71	0.38
III	229.89	62.74	17.01	3.59	0.40
IV	148.25	59.64	18.12	2.29	1.10
V	152.18	60.52	18.23	2.31	1.24
VI	127.03	60.24	18.70	2.14	0.82

Changes in crushing parameter values as a function of feed mass_ Maximum crushing force, specific energy, technical performance and crushing time_ Crushing of sandstone “Mucharz” between the flat plates

Feed size	Mass	Specific energy	Maximum crushing force	Technical performance	Crushing time	Number of samples
D	m	L_s	F_peak	W_t	t_c	i
[mm]	[kg]	[kJ/kg]	[kN]	[t/h]	[s]	[-]
90	2.01	2.71	202.14	1.71	4.23	12
90	3.44	2.83	221.81	1.79	6.93	11
90	3.92	2.9	231.93	1.84	7.69	11
90	4.78	3.02	261.98	1.93	8.9	12
90	6.2	3.1	269.94	2.07	10.8	11
90	7.37	3.07	262.80	2.13	12.44	12
90	10.2	3.12	265.43	2.14	17.13	11
90	20.5	3.11	267.32	2.12	34.81	11

Product grain size, degree of fineness

Set	I	II	III	IV	V	VI
d_80%	12.19	12.88	13.83	13.85	13.87	13.62
n_80%	7.38	6.99	6.51	6.50	6.49	6.61

Product particle size distribution for 6 sets of crushing plates

Set	I	II	III	IV	V	VI

Fraction d [mm]	Residue on sieves, share of grain fraction f_n [%]
31.5 < d	1.13	0.81	3.35	4.75	6.11	3.13
16 < d ≤ 31.5	39.92	49.15	49.35	56.82	51.58	56.69
8 < d ≤ 16	29.92	22.46	21.98	20.12	22.66	17.21
4 < d ≤ 8	11.64	10.94	10.85	7.58	7.77	9.75
2 < d ≤ 4	5.14	5.23	4.00	3.37	3.27	4.01
1 < d ≤ 2	3.68	3.44	2.97	2.16	2.25	2.65
0.5 < d ≤ 1	2.35	1.91	2.21	1.27	1.71	1.57
0.25 < d ≤ 0.5	1.99	1.62	1.51	1.04	1.34	1.40
0.125 < d ≤ 0.25	2.18	1.61	1.62	0.99	1.39	1.44
0.063 < d ≤ 0.125	2.05	1.67	0.54	1.06	1.38	1.43
d ≤ 0.063	0.66	1.17	1.62	0.84	0.54	0.73

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Application of The New Shape Crushing Plate in Machine Crushing Processes

Catégorie d'article: Research Article

Publié en ligne: 19 mars 2020

Pages: 83 - 96

Reçu: 07 mars 2019

Accepté: 18 sept. 2019

DOI: https://doi.org/10.2478/sgem-2019-0029

Mots clés
Double-toggle jaw crusher, crushing process, crushing plate, technical performance

© 2020 Paweł Ciężkowski et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Figure 1