The ZZVP-16K Self-Operated Nitrogen Relief Valve is a high-performance tank pressure protection valve designed specifically for nitrogen blanketing systems and storage tank inert gas protection applications. As a non-powered self-regulating valve, it requires no electricity, compressed air or external control signals, relying only on the tank’s internal pressure to achieve automatic pressure relief.
When tank pressure exceeds the preset value, the self-operated nitrogen vent valve automatically opens to discharge excess nitrogen and stabilize the internal pressure. Combined with a ZZYVP nitrogen supply valve, it creates a complete automatic nitrogen blanketing system that maintains a controlled positive pressure environment inside storage tanks.
This system effectively prevents air ingress, reduces product oxidation, minimizes volatile material loss and improves safety for storage tanks containing flammable, explosive, chemical and sensitive process media.
Working Principle of ZZVP Nitrogen Relief Valve (Pressure Opening Type, Normally Closed)
Pressure Setting Adjustment：The relief opening pressure is preset by adjusting the top regulating screw. The spring applies downward force to the diaphragm, keeping the valve in the normally closed position under standard operating conditions.
Tank Filling and Pressure Rise：During storage tank filling, the liquid level increases and the vapor space inside the tank is compressed, causing the internal nitrogen pressure to gradually rise. The tank pressure is transmitted through the valve body passage to the lower side of the diaphragm. When the upward pressure force exceeds the preset spring force, the diaphragm moves upward.
Automatic Nitrogen Release：The valve plug lifts upward and the valve opens, allowing excess nitrogen gas to discharge into the atmosphere or a tail gas recovery system. The tank internal pressure is gradually reduced to the required operating range.
Pressure Recovery and Valve Closing：When the tank pressure drops back to the preset value, the upward force acting on the diaphragm becomes lower than the spring force. The diaphragm and valve plug return to the closed position, stopping the nitrogen release process.
The entire process operates automatically and continuously, maintaining a stable slightly positive pressure inside the storage tank vapor space, preventing air ingress and protecting the stored medium from oxidation and contamination.
Control valves are used for precise regulation of pipeline flow, pressure, temperature and other process parameters. To ensure correct valve selection and optimal performance, please provide detailed technical data before placing an order. Non-standard sizes and customized designs can be manufactured according to customer requirements.（Unit: mm）
| DN | NPS | Type/Class | Part No | L | H | D | K | d1 | n-L | Rated KvS | Storke | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 15 | 0.5 | ZZYPBZ-150LB | XLXZZYP150X05 | 150/184 | 285 | 90 | 60.3 | 35.1 | 4-16 | 7 | 8 | |
| 20 | 0.75 | ZZYPBZ-150LB | XLXZZYP150X075 | 150/184 | 290 | 100 | 69.9 | 42.9 | 4-16 | 7 | 8 | |
| 25 | 1 | ZZYPBZ-150LB | XLXZZYP150X1 | 160/184 | 300 | 110 | 79.4 | 50.8 | 4-16 | 11 | 10 | |
| 32 | 1.25 | ZZYPBZ-150LB | XLXZZYP150X125 | 180/200 | 320 | 115 | 88.9 | 63.5 | 4-16 | 20 | 10 | |
| 40 | 1.5 | ZZYPBZ-150LB | XLXZZYP150X15 | 200/222 | 340 | 125 | 98.4 | 73 | 4-16 | 30 | 16 | |
| 50 | 2 | ZZYPBZ-150LB | XLXZZYP150X2 | 230/254 | 360 | 150 | 120.7 | 91.9 | 4-18 | 8 | 16 | |
| 65 | 2.5 | ZZYPBZ-150LB | XLXZZYP150X25 | 290/276 | 390 | 180 | 139.7 | 104.6 | 4-18 | 75 | 20 | |
| 80 | 3 | ZZYPBZ-150LB | XLXZZYP150X3 | 310/298 | 410 | 190 | 152.4 | 127 | 4-18 | 120 | 20 | |
| 100 | 4 | ZZYPBZ-150LB | XLXZZYP150X4 | 352 | 450 | 230 | 190.5 | 157.2 | 8-18 | 190 | 25 | |
| 125 | 5 | ZZYPBZ-150LB | XLXZZYP150X5 | 400 | TBD | 255 | 215.9 | 185.7 | 8-22 | 300 | 40 | |
| 150 | 6 | ZZYPBZ-150LB | XLXZZYP150X6 | 451 | TBD | 280 | 241.3 | 215.9 | 8-22 | 480 | 40 | |
| 200 | 8 | ZZYPBZ-150LB | XLXZZYP150X8 | 600 | TBD | 345 | 298.5 | 269.7 | 8-22 | 760 | 50 | |
| 250 | 10 | ZZYPBZ-150LB | XLXZZYP150X10 | 650 | TBD | 405 | 362 | 323.8 | 12-26 | 1100 | 60 | |
| 300 | 12 | ZZYPBZ-150LB | XLXZZYP150X12 | 737 | TBD | 485 | 431.8 | 381 | 12-26 | 1750 | 70 | |
| 15 | 0.5 | ZZYPBZ-300LB | XLXZZYP300X05 | 184 | TBD | 95 | 66.7 | 35.1 | 4-16 | 7 | 8 | |
| 20 | 0.75 | ZZYPBZ-300LB | XLXZZYP300X075 | 197 | TBD | 115 | 82.6 | 42.9 | 4-18 | 7 | 8 | |
| 25 | 1 | ZZYPBZ-300LB | XLXZZYP300X1 | 197 | TBD | 125 | 88.9 | 50.8 | 4-18 | 11 | 10 | |
| 32 | 1.25 | ZZYPBZ-300LB | XLXZZYP300X125 | 210 | TBD | 135 | 98.4 | 63.5 | 4-18 | 20 | 10 | |
| 40 | 1.5 | ZZYPBZ-300LB | XLXZZYP300X15 | 235 | TBD | 155 | 114.3 | 73 | 4-22 | 30 | 16 | |
| 50 | 2 | ZZYPBZ-300LB | XLXZZYP300X2 | 267 | TBD | 165 | 127 | 91.9 | 8-18 | 8 | 16 | |
| 65 | 2.5 | ZZYPBZ-300LB | XLXZZYP300X25 | 292 | TBD | 190 | 149.2 | 104.6 | 8-22 | 75 | 20 | |
| 80 | 3 | ZZYPBZ-300LB | XLXZZYP300X3 | 317 | TBD | 210 | 168.3 | 127 | 8-22 | 120 | 20 | |
| 100 | 4 | ZZYPBZ-300LB | XLXZZYP300X4 | 368 | TBD | 255 | 200 | 157.2 | 8-22 | 190 | 25 | |
| 125 | 5 | ZZYPBZ-300LB | XLXZZYP300X5 | 425 | TBD | 280 | 235 | 185.7 | 8-22 | 300 | 40 | |
| 150 | 6 | ZZYPBZ-300LB | XLXZZYP300X6 | 473 | TBD | 320 | 269.9 | 215.9 | 12-22 | 480 | 40 | |
| 200 | 8 | ZZYPBZ-300LB | XLXZZYP300X8 | 620 | TBD | 380 | 330.2 | 269.7 | 12-26 | 760 | 50 | |
| 250 | 10 | ZZYPBZ-300LB | XLXZZYP300X10 | 660 | TBD | 445 | 387.4 | 323.8 | 16-30 | 1100 | 60 | |
| 300 | 12 | ZZYPBZ-300LB | XLXZZYP300X12 | 775 | TBD | 520 | 450.8 | 381 | 16-33 | 1750 | 70 | |
| 15 | 0.5 | ZZYPBZ-600LB | XLXZZYP600X05 | 184 | TBD | 95 | 66.7 | 35.1 | 4-16 | 7 | 8 | |
| 20 | 0.75 | ZZYPBZ-600LB | XLXZZYP600X075 | 206 | TBD | 115 | 82.6 | 42.9 | 4-18 | 7 | 8 | |
| 25 | 1 | ZZYPBZ-600LB | XLXZZYP600X1 | 210 | TBD | 125 | 88.9 | 50.8 | 4-18 | 11 | 10 | |
| 32 | 1.25 | ZZYPBZ-600LB | XLXZZYP600X125 | 220 | TBD | 135 | 98.4 | 63.5 | 4-18 | 20 | 10 | |
| 40 | 1.5 | ZZYPBZ-600LB | XLXZZYP600X15 | 251 | TBD | 155 | 114.3 | 73 | 4-22 | 30 | 16 | |
| 50 | 2 | ZZYPBZ-600LB | XLXZZYP600X2 | 286 | TBD | 165 | 127 | 91.9 | 8-18 | 8 | 16 | |
| 65 | 2.5 | ZZYPBZ-600LB | XLXZZYP600X25 | 311 | TBD | 190 | 149.2 | 104.6 | 8-22 | 75 | 20 | |
| 80 | 3 | ZZYPBZ-600LB | XLXZZYP600X3 | 337 | TBD | 210 | 168.3 | 127 | 8-22 | 120 | 20 | |
| 100 | 4 | ZZYPBZ-600LB | XLXZZYP600X4 | 394 | TBD | 275 | 215.9 | 157.2 | 8-26 | 190 | 25 | |
| 125 | 5 | ZZYPBZ-600LB | XLXZZYP600X5 | 457 | TBD | 330 | 266.7 | 185.7 | 8-30 | 300 | 40 | |
| 150 | 6 | ZZYPBZ-600LB | XLXZZYP600X6 | 508 | TBD | 355 | 292.1 | 215.9 | 12-30 | 480 | 40 | |
| 200 | 8 | ZZYPBZ-600LB | XLXZZYP600X8 | 650 | TBD | 420 | 349.2 | 269.7 | 12-33 | 760 | 50 | |
| 250 | 10 | ZZYPBZ-600LB | XLXZZYP600X10 | 670 | TBD | 510 | 431.8 | 323.8 | 16-36 | 1100 | 60 | |
| 300 | 12 | ZZYPBZ-600LB | XLXZZYP600X12 | 800 | TBD | 560 | 489 | 381 | 20-36 | 1750 | 70 |
Integrated Nitrogen Blanketing System Control Logic
Product Discharge → Tank Pressure Decrease: When the storage tank is being discharged, the internal tank pressure decreases. The ZZYVP Nitrogen Supply Valve automatically opens to supply nitrogen into the tank, while the ZZVP Nitrogen Relief Valve remains closed to prevent unnecessary nitrogen loss.
Product Filling → Tank Pressure Increase: During tank filling, the vapor space inside the tank is compressed and the internal pressure rises. The ZZYVP Nitrogen Supply Valve automatically closes, while the ZZVP Nitrogen Relief Valve opens to discharge excess nitrogen gas and stabilize the tank pressure.
Extreme Overpressure / Vacuum Protection: In case of extreme overpressure or vacuum conditions, the top-mounted tank breathing valve provides additional safety protection by automatically relieving excessive pressure or preventing tank vacuum collapse, ensuring the structural safety of the storage tank.
