Pressure Vacuum Relief Valve with Flame Arrester NK-BVF70 Series

INTRODUCTION
Pressure / Vacuum relief valves are used on liquid storage tanks and other process vessels or systems to prevent structural damage due to excess internal vacuum. Storage tanks are pressurized when liquid is pumped in, compressing the existing vapor or when rising temperatures cause increased evaporation or expansion of existing vapor.Conversely, a vacuum condition may be created when pumping out or due to falling temperature. To prevent tank damage, vapor must be allowed into or out of the tank at specified vacuum condition. The volume rate of venting depends upon the tank size, volatility of the tank contents, the pumping rates and the temperature.

MODEL NAME : NK-BVF70 SERIES

DESIGN AND FUNCTION

Model No.

Type Material

Setting Pressure Range

NK-BVF70W

Weight Loaded release to ATM Aluminum, Carbon Steel, Stainless Steel

22 ~ 700 mmH2O

NK-BVF70S

Spring Loaded to ATM Aluminum, Carbon Steel, Stainless Steel

Above 700 mmH2O

Note) Other specification to be consult by factory.

A combination of the model NK-BV12, NK-BV15 pressure vacuum relief valve and model NK-FA21T flame arrester make up the model NK-BVF60, NK-BVF70. The model NK-BVF70 combination units are used for pressure vacuum relief where vapors must be piped away. The bank assemblies are designed of wafer design for easy removal from the housing to facilitate inspection and cleaning.

Pressure Relief
As the pressure in the storage tank increases, the vacuum pallet is held shut.When the set pressure is reached, the pressure pallet lifts and relieves to atmosphere (or to a header if it a pipe away valve).

MODEL NAME : NK-BVF60W

MODEL NAME : NK-BVF60S

MODEL NAME : NK-BVF70W

MODEL NAME : NK-BVF70S

Vacuum Relief
As a vacuum is drawn in the storage tank (for example, when fluid is being pumped out), the pressure pallet is held shut by atmospheric pressure. When the vacuum setting is reached, the pallet lifts and air is drawn in the storage tank from the atmosphere.

MODEL NAME : NK-BVF60W

MODEL NAME : NK-BVF60S

MODEL NAME : NK-BVF70W

MODEL NAME : NK-BVF70S

INSPECTION AND STORAGE
The vacuum relief valve is carefully packaged to prevent damage or contamination during shipping. Inspect all equipment when it is received: report any damage to the carrier immediately. The valve should be protected during handling and storage. Keep all the ports plugged to prevent intrusion of foreign materials. Before installation, inspect the unit for indications of physical damage or internal contamination. If these are observed, the valve must be disassembled, cleaned and repaired before installation.

DRAWING AND DIMENSION

SIZE I.D1 I.D2 H1 H2 L1 L2
2” x 3” 50 80 590 740 140 395
3” x 4” 80 100 645 820 165 470
4” x 6” 100 150 735 970 185 535
6” x 8” 150 200 905 1210 220 665
8” x 10” 200 250 1000 1320 253 785
10” x 12” 250 300 1145 1500 290 890
12” x 14” 300 400 1280 1685 330 1025

UNIT : mm

SIZE I.D1 I.D2 H1 H2 L1 L2
2” x 3” 50 80 590 770 150 400
3” x 4” 80 100 645 870 160 472
4” x 6” 100 150 735 1035 220 535
6” x 8” 150 200 905 1280 238 665
8” x 10” 200 250 1000 1350 253 785
10” x 12” 250 300 1145 1530 290 890
12” x 14” 300 350 1280 1710 330 1025

UNIT : mm