This standard specifies the dimensional tolerances and technical requirements for the flow-through parts of centrifugal pump castings. JB/T 6879-1993 Dimensional tolerances for the flow-through parts of centrifugal pump castings JB/T6879-1993 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T 6879-93
Dimensional Tolerances of the Flow Area of ​​Centrifugal Pump Castings
Published on July 13, 1993
Ministry of Machinery Industry of the People's Republic of China
Implementation on July 1, 1994
Mechanical Industry Standard of the People's Republic of China
Dimensional Tolerances of the Flow Area of ​​Centrifugal Pump Castings
Subject Content and Scope of Application
This standard specifies the dimensional tolerances and technical requirements for the flow area of ​​centrifugal pump castings. This standard applies to all metal castings of centrifugal pumps except light metal castings and wear-resistant white cast iron castings. 2 Basic Provisions
JB/T 687993
Dimensional tolerances of the flow area of ​​centrifugal pump castings are divided into three accuracy levels: A, B, and C. The dimensional tolerance values ​​are listed in Table 1, Table 2, Table 3 and Table 4 according to different flow-through parts. 3 Technical requirements
3.1 The accuracy grade should be selected as follows:
Grade C is a general grade. For centrifugal pumps with low performance deviation requirements, Grade C can be used; when Grade C is used, the performance deviation of the centrifugal pump cannot meet the requirements and needs to be met by changing the dimensional tolerance, Grade B can be used; impellers and guide vanes that are required to be precision cast by investment casting can use Grade A. 3.2 Castings that are required to be manufactured according to Grade C are not marked in the drawings. When it is required to be manufactured according to Grade B or Grade A, it should be indicated in the drawings or technical documents.
3.3 The impeller, guide vane and volute castings of the centrifugal pump are shown in Figures 1, 2, 3 and 4 respectively. The dimensional tolerances of the flow-through parts and the allowable tolerances of the blade misalignment values ​​of the intermediate parting should comply with the provisions in Tables 1, 2, 3 and 4 respectively. S (blade thickness)
Approved by the Ministry of Machinery Industry on July 13, 1993
Implemented on July 1, 1994
Dimension code
Qinben ruler
Dimension code
Any size
Any size
Misaligned size code
Any size
Any size
JB/T6879-93
Table 1 Impeller size tolerance
At intermediate parting. Blade misalignment
Table 2 Blade misalignment tolerance
Blade thickness
Any size
Maximum misalignment allowable value (percentage of blade thickness) Grade C
JB/T 6879-93wwW.bzxz.Net
Any size
Any size
%s0干
Any size
Basic size
Size code
Basic size
Accuracy grade
+1.5+2.0+2.
JB/T6879-93
Embedded surface
Spiral body size tolerance
±0.5±0.75±1.0±1.25%
Note: 1) If the bearing surface d, is not circular, the dimensional deviation of d, should be determined by two coordinate axes (major axis and minor axis) respectively. 2) The H value of each section of the flow channel is determined by the dimensional deviation of H only in sections 2, 4, 6, and 8. 120
3.4 ​​For high-center pumps with special requirements, when the upper deviation or lower deviation specified in the tables of Article 3.3 must be changed, only the position of the tolerance zone is allowed to be moved, and the tolerance value shall not be increased, and the upper and lower deviations shall be clearly marked on the drawing. For example: According to Table 1, the size tolerance of the bs basic size range less than 25mm is +0.7.0.2
. When the difference direction is moved, the tolerance is marked on the drawing as 0.1
3.5 The thickness of the impeller blade should not be less than 3mm for cast iron parts and 4mm for cast steel parts. 3.6 The shape of the impeller blade inlet head should comply with the following provisions: If it is necessary to shift the position of the tolerance zone upward a. The blade head radius of the blade inlet edge should be adapted to half of the blade thickness, in order to achieve a smooth transition, and no edges or corners are allowed; b. The blade inlet head radius should not be less than 0.75mm for gray cast iron, 1.5mm for ductile iron, and 2mm for cast steel.
Additional Notes:
This standard was proposed and managed by Shenyang Pump Research Institute. This standard was drafted by Shenyang Pump Research Institute. The drafter of this standard is Zhang Wenda.
People's Republic of China
Mechanical Industry Standard
Dimensional tolerance of flow-through parts of centrifugal pump castings
JB/T 687993
Published and distributed by the Mechanical Standardization Research Institute of the Ministry of Machinery Industry Printed by the Mechanical Standardization Research Institute of the Ministry of Machinery Industry (P.O. Box 8144, Beijing 100081)
Copyright reserved. No reproduction allowed
Format 880×12301/16 Printing sheet 1/2 Number of words 8,000 First edition in April 1994 First printing in April 1994 Number of copies 00,001-500 Price 3.00 yuan
No. 1169
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