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Product Description
Marine High-velocity Relief Valve DF-ISO Type
The high-velocity relief valve ( pressure/vacuum valve for cargo oil tank ) has already been generally used by the relief system of the oil tanker and chemical tanker, according to the current regulations:IMO and IBC.
IS015364:standards of Ships and Marine Technology Pressure/Vacuum Valve for Cargo Tank and the publication of the IMO.MSC/Circ.1009 Circular provide standards for designing,manufacturing, experimenting and maintaining the high- velocity relief valve.
Recently, Ship Design&Research institutes and ship- owners ask for using the high- velocity relief valve with high quality,because the relief system used for oil tanker and chemical tanker is more important for the Safety of the ship.
It is not only for ensuring the safety of the cargo oil tank and avoiding over-pressure or low- pressure, but also for controlling the fire, the danger of explosion and the releasing of the noxious gas.It also pays more attention on its practicability; provides the safest high-velocity relief valve with a good price.
Aseismatic marine high-velocity relief valve is the right product which satisfies the above demands of Ship Design&Research Institutes and ship-owners.
Basic structure of the DF high-velocity relief valve
| SN | DN | D1 | D | L | H | n-d |
| 8 | 250 | 350 | 395 | 460 | 860 | 12-φ22 |
| 7 | 200 | 295 | 340 | 460 | 860 | 8-φ22 |
| 6 | 150 | 225 | 265 | 390 | 680 | 8-φ18 |
| 5 | 25 | 200 | 240 | 340 | 665 | 8-φ18 |
| 4 | 100 | 170 | 210 | 290 | 565 | 4-φ18 |
| 3 | 80 | 50 | 190 | 290 | 545 | 4-φ18 |
| 2 | 65 | 130 | 160 | 250 | 490 | 4-φ14 |
| 1 | 50 | 110 | 140 | 250 | 490 | 4-φ14 |
| SN | Parts | Ouantity | Material | |||||||
| 1 | P-valve base | 304 | ||||||||
| 2 | P-valve seat | 304 | ||||||||
| 3 | P-valve body(a) | 304 | ||||||||
| 4 | P-valve body(b) | 304 | ||||||||
| 5 | Guiedvane director(P-valve disc) | 304 | ||||||||
| 6 | Balancing weight | 304 | ||||||||
| 7 | P-valve spindle | 316L | ||||||||
| 8 | Lifting shaft | 304 | ||||||||
| 9 | Lifting cam | 304 | ||||||||
| 10 | Positioning board | 304 | ||||||||
| 11 | Lifting handle | 304 | ||||||||
| 12 | Bush | 304 | ||||||||
| 13 | Nameplate | 304 | ||||||||
| 14 | Lifting pin | 304 | ||||||||
| 15 | V-valve bob | 304 | ||||||||
| 16 | V-valve disc | 316L | ||||||||
| 17 | V-valve seat | 316 | ||||||||
| 18 | Small spacerring of flame screen | 304 | ||||||||
| 19 | Flame screen | 2 | 316L | |||||||
| 20 | Big spacer ring of flame scerrm | 304 | ||||||||
| 21 | Flame screen gland | 304 | ||||||||
| 22 | V-valve cover or Gas-freeingcover | 1 | 304 | |||||||
It changes the design method of the valve,making sure that the valve is conceded sealed while it is closed.The experiment proves the valve will open while the pressure of the system reaches to the set pressure; the valve stem is lifted or dropped while the pressure rises and falls.The stem will never be fully lifted and cracked while it is under the maximum working pressure.
The valve will be never vibrated while the ship is moving,because the valve is concertedly sealed while it is closed.It is the best choice to release the mixture gas of the tank.
The gravity type of the high-velocity relief valve is its basic specification.It can reduce gravity and increase the magnetic force, change "becoming to make it becomes" to "becoming".The pressure difference will increase after the magnetic force is increased.Generally speaking,the Ship Design& Research Institutes and ship- owners will choose the traditional gravity type of the high- velocity relief valve for its safety.
Remark : the traditional high-velocity relief valve is in the contact seal while it is closed .
Main Technical Parameters
| Model | Setting opening pressure (kPa) | Rated working pressure (kPa) | Flow rate (m³/h) | MESG (mm) | Pressure valve outlet velocity (m/s) | |||
| Presure valve | Vacuum valve | Pressure valve | Vacuum valve | Pressure valve | Vacuum valve | |||
| DF50 | 14.0~21.0 | 3.5~-7.0 | 21.0 | -7.0 | >300 | >300 | ≥0.65 | >30 |
| DF65 | 14.0~21.0 | 3.5~-7.0 | 21.0 | -7.0 | >400 | >400 | ≥0.65 | >30 |
| DF80 | 14.0~21.0 | 3.5~-7.0 | 21.0 | -7.0 | >600 | >500 | ≥0.65 | >30 |
| DF100 | 14.0~21.0 | 3.5~-7.0 | 21.0 | -7.0 | >800 | >600 | ≥0.65 | >30 |
| DF125 | 14.0~21.0 | -3.5~-7.0 | 21.0 | -7.0 | >1000 | >800 | ≥0.65 | >30 |
| DF150 | 14.0~21.0 | -3.5~-7.0 | 21.0 | -7.0 | >2500 | >2000 | ≥0.65 | >30 |
| DF200 | 14.0~21.0 | 3.5~-7.0 | 21.0 | -7.0 | >3000 | >3000 | ≥0.65 | >30 |
| DF250 | 14.0~21.0 | 3.5~-7.0 | 21.0 | -7.0 | >3500 | >3000 | ≥0.65 | >30 |
The standardized flange of the high-velocity relief valve is connected with the pipe flange of the cargo oil tank,and the mixed compressed gas will be formed when the cargo oil tank is loading cargoes.The valve on the pressure valve with the block will spring out in a flash,at the same time the valve will open while the pressure of the compressed gas reaches to the set pressure(the oil tank is 14kPa.chemical tank is 20kPa),then release the mixed compressed gas to the air with the speed of more than 30m/s (it will be more than 30m/s under the regular operation).
