6.3 Gap between impeller and pump housing/cover
(wear rings)
A leak flow (1) will occur in gap (2) between the rotating impeller
and the stationary pump housing when the pump is operating. Leak
flow (1) returns to impeller inlet (3) through gap (2).
Thus, the impeller must pump both leak flow (1) and the fluid
through the pump from inlet (3) flange to outlet (4) flange. To
minimize leak flow (1), an interchangeable wear ring (impeller seal)
(A) is mounted.
1
3
4
2
A
TM080466
We recommend that the seal gap never exceeds the maximum limit
curve calculated according to an efficiency loss of maximum 2%.
0
0.00
0.20
0.40
0.60
0.80
1.00
50
100
150
X
Y
200
250
300
350
TM080467
X
Outlet DN
Y
Maximum seal gap [mm]
Tolerance table
If the difference exceeds the maximum seal gab according to the
above limit curve, the below table informs whether the wear ring or
the impeller is worn out.
GG pump h bronze wear ring + GG impeller
Wear ring inside
Impeller outside
Nominal
diameter
Max.
tolerance
Min.
tolerance
Nominal
diameter
Max.
tolerance
Min.
tolerance
76
0.225
0.15
75.95
-0.2
-0.274
76
0.225
0.15
75.95
-0.2
-0.274
76
0.225
0.15
75.95
-0.2
-0.274
63
0.22
0.15
62.95
-0.19
-0.264
90
0.245
0.17
89.95
-0.22
-0.307
90
0.245
0.17
89.95
-0.22
-0.307
100
0.245
0.17
99.95
-0.22
-0.307
100
0.245
0.17
99.95
-0.22
-0.307
100
0.245
0.17
99.95
-0.22
-0.307
112
0.25
0.17
111.95
-0.24
-0.327
112
0.25
0.17
111.95
-0.24
-0.327
112
0.25
0.17
111.95
-0.24
-0.327
122
0.265
0.185
121.95
-0.26
-0.36
130
0.265
0.185
129.95
-0.26
-0.36
130
0.265
0.185
129.95
-0.26
-0.36
154
0.275
0.195
153.95
-0.28
-0.38
154
0.275
0.195
153.95
-0.28
-0.38
185
0.3
0.21
184.95
-0.34
-0.455
185
0.3
0.21
184.95
-0.34
-0.455
185
0.3
0.21
184.95
-0.34
-0.455
200
0.31
0.22
199.95
-0.34
-0.455
144
0.275
0.195
143.95
-0.28
-0.38
224
0.31
0.22
223.95
-0.38
-0.495
174
0.3
0.21
173.95
-0.31
-0.41
224
0.31
0.22
223.95
-0.38
-0.495
210
0.31
0.22
209.95
-0.38
-0.495
222
0.25
0.05
221.95
-0.38
-0.495
230
0.25
0.05
229.95
-0.42
-0.54
240
0.25
0.05
239.95
-0.42
-0.535
260
0.25
0.05
259.95
-0.48
-0.61
250
0.25
0.05
249.95
-0.42
-0.535
27
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