主要用于電站鍋爐、壓力容器、減溫減壓裝置上使用，防止壓力超過允許zui高壓力值，保證設備安全運行。

This valve is used for power plant boilers, pressure containers, pres-
sure and temperature reducing device and other facilities. It serves to pre- vent the pressure exceeding the highest allowable pressure value and ensure the safety of the device when working.

1、當介質壓力升高到整定壓力時，沖量安全閥打開，介質從脈沖管進入主安全閥的活塞室，推動活塞下降，使閥門自動打開，當沖量閥關閉時，閥瓣又自動關閉。

2、密封面用鈷基鉻鎳不銹鋼堆焊而成，閥瓣經熱處理，提高了耐磨性和抗沖蝕性。

1. When the medium pressure rises to the set pressure, the implse
safety valve opens, and the medium in the impulse pipe eners into the pis- ton chamber of the main safety valve from impulse pipe, forcing the piston to descend, and then the valve automatically opens; when the impulse safety valve closes, the disc will also automatically close.
2. The sealed surface is made of Fe base stainless steel by overiaying welding. Through thermal treatment, the wear resistance and anti-erosion of
disc is improved.

1. The main safety valve shall be installed vertically at the highest posi- tion of the deivce.
2. The main safety valve shall be fastened upon the gallow, which sus- tains the back-seat force produced in the steam discharging process of the main safety valve.
3. The exhaust pipe shall contain a special gallow to prevent the force of its weight directly applying on the main safety valve. The connecting lange between the main safety valve and exhaust pipe shall eliminate anyex- tra stress.
4. At the lowest point of the exhaust pipe, water drainage shall be taken into onsideration to avoid producing water hammer whil discharging

Type

DN Nominal diameter

Connecting dimensions

L

L1

L2

H

D

D1

D2

b

z-d

DN'

D'

D1'

D2

b'

z'-d'

A49H-4

150

220

230

240

486

300

250

204

30

8-25

200

360

310

278

34

12-25

A49H-4

200

270

295

330

615

375

320

260

38

12-30

300

485

430

390

40

16-30

A49H-4

250

300

350

370

646

445

385

313

42

12-34

350

550

490

450

44

16-34