Safety shut-off valve
Abbreviation: emergency shut-off valve, pneumatic shut-off valve, ammonia tank shut-off valve, storage tank shut-off valve
Model: QDQ421F-25/40C QDQ421F-25/40P
Introduction to safety shut-off valve:
The full name of the safety shut-off valve is the safety emergency shut-off valve. As an auxiliary safety protection valve for the liquefied gas filling station and ammonia station, the emergency safety shut-off valve is a kind of safety protection valve. The drive part and valve body part are separated, so it is easier to repair and replace the vulnerable parts (cylinder O-ring).
Features of tank shut-off valve:
1. It is applicable to gas or liquid ammonia pipeline for safety protection. The valve is normally closed. During the loading and unloading process, the air source pressure pushes the cylinder piston and the valve opens.
2. The principle of check valve to prevent backflow is adopted, and the spring return function of safety valve is used. Only one-way media is cut off. During installation, the flow direction of media must be consistent with the identification of valve body.
3. In case of pipeline leakage, the remote control valve can be closed by pressure relief of air source. In case of fire, the high temperature will melt the fusible plug, exhaust the air source pressure, and the valve will automatically close.
4. It can be equipped with explosion-proof solenoid valve, air filter pressure reducing valve and travel switch to realize automatic control
5. Simple operation and fast valve closing.
Technical parameters of safety shut-off valve:
| Nominal pressure MPa | two point five | four |
| Shell test pressure MPa | three point seven five | six |
| Sealing test pressure MPa | two point seven five | four point four |
| Applicable temperature | -40℃~+50℃ |
| Applicable media | Liquefied petroleum gas, vinyl chloride, liquid ammonia, etc |
| Flange standard | GB/T9113-2000 |
| Manufacturing standard | JB/T9094-1999 |
| Emergency cut-off time | ≤ 10~30 seconds |
| Melting temperature of fusible plug | 75± 5℃ |
| Applicable medium of cylinder | Compressed air, nitrogen |
| Air source pressure MPa | 0.3~0.6 |
Materials of main parts of pneumatic shut-off valve:
| valve body | Stem | Valve disc | Spring | a seal | Cylinder | seal ring |
| WCB,CF8 | 20Cr13 | 20Cr13 | 50CrVA,1Cr18Ni9 | PTFE | 20# | NBR |
Emergency shut-off valve QDQ421F nominal pressure PN2.5Mpa overall dimensions and connection dimensions
| DN | L | D | D1 | D2 | D3 convex | D4 convex | b | f | Z-φ | H |
| twenty-five | one hundred and sixty | one hundred and fifteen | eighty-five | sixty-five | fifty-seven | fifty-eight | sixteen | four | 4-φ fourteen | two hundred and sixty-two |
| thirty-two | one hundred and eighty | one hundred and forty | one hundred | seventy-six | sixty-five | sixty-six | eighteen | four | 4-φ eighteen | two hundred and forty-five |
| forty | two hundred | one hundred and fifty | one hundred and ten | eighty-four | seventy-five | seventy-six | eighteen | four | 4-φ eighteen | three hundred and twenty-one |
| fifty | two hundred and thirty | one hundred and sixty-five | one hundred and twenty-five | ninety-nine | eighty-seven | eighty-eight | twenty | four | 4-φ eighteen | three hundred and forty-six |
| eighty | three hundred and ten | two hundred | one hundred and sixty | one hundred and thirty-two | one hundred and twenty | one hundred and twenty-one | twenty-four | four | 8-φ eighteen | four hundred and thirty-five |
| one hundred | three hundred and fifty | two hundred and thirty-five | one hundred and ninety | one hundred and fifty-six | one hundred and forty-nine | one hundred and fifty | twenty-four | four point five | 8-φ twenty-two | four hundred and sixty |
