Machine Drawing

Part Drawings 377

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d:\N-Design\Des19-1.pm5

flange of the cock is fitted to the boiler shell, whereas the bottom flange is fitted to the pipe,

carrying the water and sediments. The assembly drawing of a blow-off cock is shown in Fig. 19.17.

Slot to be milled

Workpiece

1 8 2 9 7 11 5

6

12

22

14

f 10

f 5 22

R12

f 8

120562612

20

R6

20

R14

R12

18 18

136

204

76

10

(^43)
4
28
10
22
34
4
14
16
28
48
16
10
10 14
18
M8
3
1818
f^20
(^2010)
8
8
28
12
16
20 686
(^4214)
6
Part No. Name Matl. Qty.
1 2 3 4 5 6
Fixture base
Clamp
Setting block
Flattened location pin
Clamping screw with spring
Clamping nut
CI
MS
MS
HCS
MS
MS
1 2 1 1 2 2
Parts list
Part No. Name Matl. Qty.
7
8
9
10
11
Tenon
Locating pin
Locating pin
Dowel pin
Guide pin
HCS
HCS
HCS
HCS
HCS
2
2
2
2
2
16
101055
Fig. 19.14 Milling fixture

The blow-off cock comprises a hollow conical cock 2 fitting into the corresponding hole in

the body 1. Both the cock and the body have vertical slots and when the slot in the cock is brought

in line with the slot in the body, water flows out of the boiler. By turning the cock through 90°,

the passage may be closed. To prevent leakage of water, gland 3 is tightened to the body. A

keyway is provided in the gland cover to make sure that the cock is closed before the handle is

removed.