Current Development Status and Trends of Domestic Reciprocating Jaw Crushers

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The reciprocating jaw crusher is a primary crushing device in sand and gravel plants. The differences between domestic and foreign products are analyzed mainly from three aspects below. 1. Product varieties and specifications: Jaw crushers are specified by the length and width of their feed inlet; domestic manufacturers generally produce around 8 different specifications of coarse crushing machines in accordance with industry standards. Products from major international manufacturers come in more specifications. For example: Nordberg, part of the Metso Group, offers 22 different models in three series – C, VB, and Heavy ； Cedar Company of the Terex Group offers 28 different specifications ； Pioneer Company of Astek Group offers 15 specifications. 　　What our country is currently lacking are large-size varieties: defined by an inlet size of 750mmX1060mm or larger. There are only 3-4 types of large-sized products manufactured by various manufacturers. Among the 11 specifications in Nordberg’s C series, 9 are of larger sizes, and Cedar also has 9 such specifications. A wide range of large-scale varieties is available, allowing for the selection of suitable primary crushing equipment for the construction of large-scale sand and gravel plants. 2. Product performance: The main technical parameters of the reciprocating jaw crusher are its processing capacity and the maximum allowable feed size. For pendulum jaw crushers of the same specification, their maximum allowable feed size varies due to differences in design. China follows the former Soviet Union standards, using the distance between the tip (or bottom) of the fixed tooth plate and the bottom (or tip) of the movable tooth plate as the basis for determining the feed opening width; whereas many international companies use the distance between the fixed and movable tooth plates instead. As a result, products labeled as having the same specification are actually often one tooth depth smaller compared to those produced by foreign companies. For larger-sized crushers, the tooth depth is 60–100 mm, so the allowable feed size for domestic products is usually 50–80 mm smaller. The discharge opening of the reciprocating jaw crusher can be adjusted, and different discharge openings correspond to varying processing capacities. Therefore, when comparing processing capacity, the size of the discharge opening should be kept the same. For example, the C100 reciprocating jaw crusher manufactured by Nordberg has a processing capacity of 265 t/h when the setting for the closed-side discharge opening (C, S, S) is 125 mm; domestically, the corresponding model is the PE750X1060 ； The processing capacity is 195 t/h, which is about 25% lower. Therefore, on a sand and gravel production line with a capacity of 250X300 t/h, using the C100 model as the primary crushing equipment can meet the requirements, while the PE750X1060 model is only just sufficient for this purpose. 3. Product design and manufacturing processes: Over the past 20 years, significant progress has been made in the four-link mechanical design theory related to the motion mechanism of reciprocating jaw crushers. For example: the bidirectional meshing angle in the crushing chamber, large swing angles of the short elbow plates, and reduction of the transmission angle and eccentricity. Products offered by foreign companies often employ these proven advanced design principles to enhance product performance and reliability. For various reasons, domestic manufacturers in our country rarely employ advanced design theories; their mainstream products are almost all those designed before the 1970s. They use wear-resistant materials such as high-manganese steel, as well as domestically produced basic components like self-aligning roller bearings, resulting in a service life that is lower than that of similar products of international standard. Furthermore, the machining and assembly processes used by the original equipment manufacturers have seen little change over the years, such as those for machining and assembling bearing holes and bearing seats, as well as for machining and assembling the frame.