Technical requirements for experimental methods of hydraulic gear pump
Technical requirements for experimental methods of hydraulic gear pump
① General requirements. The general requirements shall comply with the following provisions, and the products with special requirements shall be agreed by the supplier and the demander.
The pressure rating shall comply with the provisions of GB / T 2346; the nominal displacement shall comply with the provisions of GB / T 2347; the installation connection size shall comply with the provisions of GB / T 2353; the type and size of threaded connection port shall comply with the provisions of GB / T 2878; other technical requirements shall comply with the provisions of 4.3 in GB / T 7935-2005; the manufacturer shall state the applicable conditions and environmental requirements of the product in the product samples and relevant data.
② Performance requirements. The performance requirements of gear pump shall include:
a. Displacement. The no-load displacement should be in the range of 95% - 110% of the nominal displacement.
b. Self absorption property. The self-priming capacity shall not be less than 16kpa vacuum degree.
c. Volume efficiency and total efficiency. Under rated conditions, when the oil temperature is 50 ℃, the volumetric efficiency and total efficiency shall meet the requirements of the following table.
Volumetric efficiency and total efficiency of gear pump
|
Rated pressure / MPa |
效率/% |
公称排量/mL·r-1 |
|||||
|
≤2 |
＞2～4 |
＞4～10 |
＞10～25 |
＞25～50 |
＞50 |
||
|
2.5 |
容积效率 |
≥70 |
≥80 |
≥90 |
≥91 |
≥93 |
|
|
总效率 |
≥60 |
≥68 |
≥77 |
≥80 |
≥82 |
||
|
10～25 |
容积效率 |
≥80 |
≥85 |
≥89 |
≥90 |
||
|
总效率 |
≥72 |
≥75 |
≥79 |
≥81 |
|||
d. Noise. Under the rated pressure and speed of 1500r / min (when the rated speed is less than 1500r / min, under the rated speed), the noise value shall meet the requirements of the following table.
Noise level of gear pump
|
额定压力/MPa |
公称排量/mL·r-1 |
||||
|
≤10 |
＞10～25 |
＞25～50 |
＞50～100 |
＞100 |
|
|
2.5 |
≤70 |
≤75 |
≤76 |
≤78 |
≤80 |
|
10～25 |
≤80 |
≤85 |
≤85 |
≤90 |
≤90 |
e. Pressure swing. For gear pump with rated pressure of 2.5MPa, the outlet pressure swing value shall not be greater than ± 0.2MPa.
f. Low temperature performance. The pump shall be able to start at - 20 ℃ under normal or no-load conditions.
g. High temperature performance. The gear pump shall be able to work normally for a short time when the inlet oil temperature of the gear pump reaches 90 ℃ under the rated working condition or the high temperature specified in the design.
h. Low speed performance. The gear pump with rated pressure of 10-25mpa shall be able to maintain stable rated pressure and volume efficiency of not less than 60% under the condition of 800r / min or the minimum speed specified in the design.
i. Overspeed performance. When the driving speed of the gear pump reaches 110% of the rated speed or the maximum speed specified in the design, the gear pump shall be able to operate normally for a short time.
j. Sealing performance. The static sealing parts should not leak oil under any working conditions, and the dynamic sealing parts should not drip oil within 4H of gear pump operation.
k. Overload performance. Under rated speed and one of the following pressure conditions, gear pump should be able to work normally for a short time.
·125% of the rated pressure (when the rated pressure is less than 20MPa).
·125% of the rated pressure or the maximum pressure specified in the design (when the rated pressure is greater than or equal to 20MPa).
l. Durability. The durability test can be conducted in any of the following schemes.
·Full load test 3000h.
·Overload test is 100h, impact test is 400000 times (on two pumps respectively).
Note: special purpose gear pump can be carried out according to special technical specification.
After the durability test, the volumetric efficiency shall not be less than three percentage points of the value specified in Schedule 8; the parts shall not have abnormal wear and other forms of damage.
③ Assembly requirements
a. The assembly shall comply with 4.4 ~ 4.7 of GB / T 7935-2005.
b. The internal cleanliness index of gear pump shall meet the requirements in the table below.
Internal cleanliness index of gear pump
|
公称排量/mL·r-1 |
清洁度指标值/mg |
|
|
铝壳体 |
铸铁壳体 |
|
|
≤10 |
≤30 |
≤60 |
|
10～50 |
≤40 |
≤70 |
|
50～100 |
≤60 |
≤100 |
|
100～200 |
≤70 |
≤120 |
|
＞200 |
≤100 |
≤180 |
c. The assembled gear pump shall be filled with 0.16mpa gas in the closed pump body without air leakage.
④ Appearance requirements. The appearance of the product shall comply with 4.8 and 4.9 of GB / T 7935-2005.
