A Condition Monitoring Method of Hydraulic Gear Pumps Based on Multilevel Mechanism-Data Fusion

Table 3

Test data of hydraulic gear pump at an oil temperature of 50°C and a no-load flow rate of 37.7 L/min.

Number of tests	Pressure (MPa)	Steady flow (L/min)	Volumetric efficiency
1	1	37.57	0.9965
2	4	37.14	0.9853
3	7	36.67	0.9729
4	10	36.16	0.9591
5	13	35.59	0.9439
6	16	34.96	0.9272
7	19	34.26	0.9087
8	22	33.50	0.8885
9	25	32.66	0.8663
10	28	31.74	0.8419
11	31	30.74	0.8153
12	34	29.64	0.7863
13	37	28.46	0.7546
14	40	27.15	0.7201
15	43	25.73	0.6824
16	46	24.17	0.6415
17	49	22.51	0.5971
18	52	20.69	0.5488
19	55	18.71	0.4964
20	58	16.57	0.4396
21	61	14.25	0.3781
22	64	11.74	0.3115
23	67	9.03	0.2394
24	70	6.09	0.1615
25	73	—	—