Company Index on m.ecvv.com

Specifications

High-velocity relief valve (pressure vacuum valve) is the controlled venting system which is necessary for oil tanker and chemical .tanker. The series of DF-type P/V valve is a new generation production without vibration and anti-collision...The pressure/vacuum valve is installed on the vent pipe of oil tanker and chemicals tanker. It is the only entry and exit for liquid cargo tank. 1. When loading the liquid cargo or ballasting, the pressure valve in the high velocity relief will open, then jet out combustible liquid cargo vapour/air-mixture in liquid cargo tank with the rate of more than 30m/s, and dilute in the air so that it will never drop on the deck. 2. When unloading the liquid cargo, the vacuum valve in the high velocity relief valve will open, then supply air to cabin safely so as to avoid the cabin is over-vacuumed. 3. When the tank navigate on sea, the high velocity valve can automatically adjust the pressure oscillation in the cabin which caused by temperature changes. The experiment of pressure/vacuum valve for cargo ships is done in the lab that is approved by the state organs. It is ratified by China Classification Society and some other classification societies through the following tests according to the above standards: 1. Fire Resistant Test 2. Re-burning Test 3. Frozen Test 4. Corrosion Resistant Test 5. Flowing Test

FEATURES and BENEFITS

1. Reliable operations reduces vapor losses
2. Suaitable and compact design ensures long-term maintenance free life cycle
3. Meet new IMO & MED requirements for cargo vapor flammability - MESG 0.65 mm
4. Non-oscillating performance
5. Full lifting and high flow capacity
6. Variable application for usable installation vent pipe length and flow capacity range
7. No peak pressure over opening pressure
8. No need inside maintenance
9. Available outside inspection, cleaning and maintenance without disassembling
10. Adjustable outside opening and closing pressure without exhausting vapor gas

Main performance parameter

Model	Opening pressure (kPa)		Rated working pressure (kPa)			Flow rate (m3/h)			Outlet air flow velocity of pressure valve(m/s)
Model	Pressure valve	Vacuum valve	Pressure valve	Vacuum valve	Air removal cover	Pressure valve	Vacuum valve	Air removal cover	Outlet air flow velocity of pressure valve(m/s)
DF50	14.0-21.0	-3.5~-7.0	21.0	-7.0	2.0	＞350	＞350	＞250	＞30
DF65	14.0-21.0	-3.5~-7.0	21.0	-7.0	2.0	＞350	＞350	＞250	＞30
DF80	14.0-21.0	-3.5~-7.0	21.0	-7.0	2.0	＞600	＞500	＞400	＞30
DF100	14.0-21.0	-3.5~-7.0	21.0	-7.0	2.0	＞800	＞600	＞400	＞30
DF125	14.0-21.0	-3.5~-7.0	21.0	-7.0	2.0	＞1000	＞800	＞600	＞30
DF150	14.0-21.0	-3.5~-7.0	21.0	-7.0	2.0	＞2500	＞2200	＞900	＞30
DF200	14.0-21.0	-3.5~-7.0	21.0	-7.0	2.0	＞3000	＞3000	＞1200	＞30
DF250	14.0-21.0	-3.5~-7.0	21.0	-7.0	2.0	＞3500	＞3500	＞1200	＞30

Remarks:

1. The high-velocity relief valves with different specification have the same diameter and performance parameter;

2. The opening pressure of the vacuum valves are -3.5kpa; the opening pressure of the pressure valves on the oil tank is 14kpa,on the chemical tank is 20kpa.The opening pressure of the pressure may be different, but the differences of opening pressure and flow range if the pressure valves have the same diameter.

Main Parts of the DF-ISO high velocity relief valve

Serial No.	Parts	Quantity	Material	Remarks
1	P-valve base	1	ZG200-400	Cast 20#
2	Water nozzle	1	0Cr18Ni9	SUS304
3	P-valve seat	1	0Cr18Ni9	SUS304
4	P-valve disc	1	0Cr18Ni9	SUS304
5	Matching block	1	0Cr18Ni9	SUS304
6	P-valve body (A) (B)	1	ZG200-400	Cast 20#
7	Conducting machine	1	0Cr18Ni9	SUS304
8	Handle	1	0Cr18Ni9	SUS304
9	V-valve body	1	ZG200-400	Cast 20#
10	Matching block	1	0Cr18Ni9	SUS304
11	V-valve disc	1	0Cr18Ni9	SUS304
12	V-valve seat	1	0Cr18Ni9	SUS304
13	Flame screen	2	00Cr17Ni14Mo2	SUS304
14	Flame screen gland	1	ZG200-400	Cast 20#
15	Nameplate	1	0Cr18Ni9	SUS304
16	Climbing pole	1	0Cr18Ni9	SUS304
17	Gas-freeing cover or V-valve cover	1	ZG200-400	Cast 20#

Remarks : The materials mentioned before are basic materials , ship-owners can choose better materials , Such as SUS304,SUS304L ,SUS316L .

The dimension parameter of the DF-ISO high velocity relief valve

Serial No.	DN	D2	D1	D	L	H	Assembly hole
8	250	320	350	395	460	860	12x22
7	200	268	295	340	455	850	8x18
6	150	202	225	265	385	710	8x18
5	125	178	200	240	380	665	8x18
4	100	148	170	210	285	565	4x18
3	80	128	150	190	285	535	4x18
2	65	110	130	160	255	485	4x14
1	50	90	110	140	255	485	4x14

Remarkss: flange executive standards: GB2501-89, DN50-DN150,nominal pressure is 0.6MPa; DN200, DN250,nominal pressure is 1.6MPa(is equal to ISO2084-1975, ISO2441-1975).