Welding fume extraction - hood tips

Welding fume extraction - hood tips
NO.1 The Suction Hood should be placed facing the welder

The hood should face the welder and be placed in a position to draw the fumes away from the welder's breathing area. Whether the hood is placed in front of, to the left, or to the right of the welder, it should be placed facing the welder to effectively capture the welding fumes and remove harmful fumes before they are inhaled by the welder.

NO.2 Placement distance between suction hood and smoke source

The hood should be captured close to the source of the fume generation, without obstructing the welder's work space. The hood also cannot be placed too far from the source of the smoke, as crosswinds may blow the smoke out of the effective capture area and spread the smoke to other areas of the workshop.

So, what is the ideal distance between the fume source and the hood? Generally, a distance equivalent to the diameter of the extraction arm is used. For example, for an 8" diameter extraction arm, the hood should be placed 8" from the source of the flue gas.

NO.3 Ingenious suction hood design can improve capture efficiency

Many hoods on the market are round or oval. In this case, the hood draws more air behind the hood, thereby reducing the amount of smoke trapped in the front.

The hood shape of the Nederman NEX MD and NEX HD Extraction Arms is cleverly designed to expand or even double the fume capture range of the hood. In addition, the design of the bottom edge of the suction hood helps to cut off the flow of non-target gas, so as to focus on trapping the target gas, which greatly improves the capture efficiency of welding fumes.
NO.4 The suction hood is different from the overall ventilation

It has been common practice in the past to install integral ventilation above the welding operation to remove welding fumes. Integral ventilation is not effective in preventing harmful fumes from reaching the welder's breathing zone. The hood also cannot be used for overall ventilation.

NO.5 Under what circumstances can the extraction arm be used for dust removal?

Extraction arms and hoods differ from vacuum cleaners in that they are low-vacuum fume capture devices that do not have enough suction to capture heavy particles that fall on surfaces. However, they can be used in applications such as compounding. Dust-splattering processes such as cutting or grinding can often be removed using a sanding table or a high-vacuum kit.

NO.6 The suction hood will not suck away the protective gas

Pulling shielding gas out of the torch requires suction equal to that of a vacuum cleaner. The vacuum pressure of a hood is much lower than that of a vacuum cleaner or high vacuum tool kit. Therefore, they do not affect the shielding gas.

NO.7 Consider the size of the extraction arm before installation

The extraction arm requires 3-4 feet of space in height and is between 3 and 16 feet in length. For a smooth installation and use of the hood, make sure you choose the size and length of the extraction arm to fit your working space.

NO.8 Excessive bending of the extraction arm may reduce the air volume

If the extraction arm is bent too much, the airflow will be blocked and the air volume will be limited, reducing the fume capture capacity of the hood. Therefore, it is very important to choose the correct size and length of extraction arm.