Machine Drawing

Assembly Drawings 315

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d:\N-Design\Des18-3.pm5

Fig. 18.35 Pressure relief valve

18.4.9 Lever Safety Valve

Safety valves are used to release some of the steam from the boiler when the pressure rises higher

than the safe limit.

In a lever safety valve, a load is applied through a lever, by placing a suitable weight at

some distance from the centre line of the valve to counter-balance the steam pressure in the

boiler. The distance can be adjusted by moving the weight along the lever for adjusting the

blowing-off pressure. The lever safety valves are suitable for stationery boilers.

12

f^3

30°

1×45° 8 14

26

f^9 f 14

1.5 10

16

M20f

(^11) f^6 M8
30 A/F
3 3
4 18
2
30 22
1×45°
f^5
M8
4
1.5
3
7
f^20 f^30
9
M8
f 3
5
6
40
f^5
1×45°
3
30 A/F
10 12
2
M8M20
6
30
f^10
30°
1×45°
17 f^3 f^6
f^5
f^11
10
92
24 3 40
3
Por t B 30°
16
D
f^6 f^8 f^14
M20
14
(^48) f^11
E
16 3
3
f 5
f 8
8
Por t C
(^1) Por t A 48
Por t C
f^30
E 12
R8
R8
PORT B
M12 DEEP 9
30
f 5
35
28
R8
30
D
f 64
22
10
5 R5 15°
6 15
18
M8 f 3
8 f 20
3
No. Name Matl. Qty
1 2 3 4 5 6 7 8 9
10
11
12
Body
Valve member
Adjusting screw
Sealed adapter
Control screw
Adapter
Control rod
Control knob
Washer
Seal
Spring : wire dia
1mm : OD = 8
Locknut M8
f
1 1 1 1 1 1 1 1 2 2 1 1
CI
MS
MS
MS
MS
MS
MS
Ebonite
Rubber
Rubber
Spring S
MS
Parts list