DeVilbiss HVLP Gravity Feed Spraygun Spécifications télécharger pdf (Page 4)

Introduction

The spray gun is the key

component in a finishing system. It

is a precision engineered and

manufactured instrument. Each

type and size is specifically

designed to perform a certain,

defined range of tasks.

As in most other areas of finishing

work, having the right tool for the

job goes a long way toward get-

ting professional results.

This chapter will help you know

which is the proper gun by review-

ing the Conventional Air and High

Volume/Low Pressure spray gun

designs commonly used in finish-

ing – suction feed, gravity feed and

pressure feed. It will also review the

different types of guns and

components within each design.

A thorough understanding of the

differences between systems will

allow you to select the right gun, to

use it properly to produce a high

quality finish and to contribute

toward a profitable finishing

operation.

SPRAY GUN TYPES

1. What is an air spray gun?

An air spray gun is a tool which

uses compressed air to atomize

paint, or other sprayable material,

and to apply it to a surface.

Air and material enter the gun

through separate passages and are

mixed at the air cap in a controlled

pattern.

2. What are the types of air spray

guns?

Air spray guns may be classified in

various ways. One way is by the

location of the material container:

Figure 1 shows a gun with a cup

attached below it.

Figure 3 shows a gun with a cup

attached above it.

Figure 4 shows a material container

some distance away from its

pressure feed gun.

The type of material feed system is

also a way of classifying guns:

Suction Feed...draws material to

the gun by suction as in Figure 1.

Gravity Feed...the material travels

down, carried by its own weight

and gravity as in Figure 3.

Pressure Feed...the material is fed

by positive pressure as in Figure 4.

Guns may also be classified as

either external or internal mix

depending upon the type of air

cap.

3. What is a suction feed gun?

A spray gun design in which a

stream of compressed air creates a

vacuum at the air cap, providing a

siphoning action. Atmospheric

pressure on the material in the suc-

tion cup forces it up the suction

tube, into the gun and out the fluid

tip, where it is atomized by the air

cap. The vent holes in the cup lid

must be open. This type gun is

usually limited to a one-quart, or

smaller, capacity container and low

to medium viscosity materials.

Figure 1- Suction Feed Gun with

attached cup

Suction feed is easily identified

by the fluid tip extending slightly

beyond the face of the air cap,

see figure 2.

Figure 2 - Suction Feed Air Cap

Suction feed guns are suited to

many color changes and to small

amounts of material, such as in

touchup or lower production

operations.

4. What is a gravity feed gun?

This design uses gravity to flow the

material from the cup, which is

mounted above the gun, into the

gun for spraying. No fluid pick-up

tube is used, since the fluid outlet

is at the bottom of the cup.

This cup has a vent hole at the top

of the cup that must remain open.

It is limited to 32 ounce capacities

due to weight and balance.

Gravity feed guns are ideal for

small applications such as spot

repair, detail finishing or for finish-

ing in a limited space. They require

less air than a suction feed gun,

and usually have less overspray.

Figure 3 - Gravity Feed Gun with

attached cup

2. Air Atomizing Spray Guns

4

1 2 3 4 5 6 7 8 9 ... 29 30

Commentaires sur ces manuels

Pas de commentaire