Device Selection

After the form of the circulation system is determined, it is necessary to determine the equipment required by the system. These equipment include: equipment in the central paint supply system, spray station outlet components and pipelines.

1. Equipment in the central paint supply system

(1) Pump

The pump is the core of the paint supply system, and the selection of the pump usually takes into account the flow, pressure, chemical compatibility and driving mode. The determination of the flow rate should consider the paint sprayed during painting and the amount of paint required by the system circulation; the determination of the pressure should consider the pressure required for paint spraying and the pressure loss in the pipeline. In order to ensure the reliability of the system, when considering the flow rate, it is generally considered in accordance with the operating frequency of no more than 20 times/min, which is beneficial to ensure the stability of the system. When choosing a pump, the four-ball plunger pump is preferred, because it has more stable performance and longer life than the general double-ball pump, and at the same time, the shear is much smaller than that of the centrifugal pump.

(2) Paint control components

Paint control components include regulators, filters, back pressure regulators, agitators, feed pumps, pressure gauges, etc. The selection of these components mainly considers the matching of materials, pressure, flow, etc. with the main circulating pump. For water-based coatings and shear-sensitive materials, low-shear components should be used; the choice of agitator should match the size of the paint bucket.

(3) Air/hydraulic oil control components

Air/hydraulic oil control components include air filters, lubricators, pressure regulators, runaway protectors and related valves, pipes and joints.

(4) Paint cans

Paint cans are containers used to store paint to meet the needs of spraying, but the design of paint cans must avoid the occurrence of paint precipitation. At the beginning, the inner wall of the paint can must be as smooth as possible, without grooves and dead corners, and the weld must be polished and polished, so as to reduce paint adhesion and reduce the obstacle to the paint overturning; and the size of the paint can should be based on Especially the consumption and pipeline capacity are determined by the packaging of nuclear materials, and the necessary sealing can prevent the pollution of the external environment. It is usually necessary to use stainless steel, and the return pipe should extend below the liquid level to prevent bubbles from forming on the paint surface. For water-based paint, electrolytic polishing and passivation of the tank are required; for containers with heat preservation, a page control device is indispensable, which can effectively prevent the generation of condensed water or paint and the pollution of the paint.

Second, the outlet components of the spray station

The outlet components of the spray station include paint and air, including paint and air pressure regulators, gun down pressure regulators, spray gun quick-change connectors, valves, hoses and joints, etc. For automatic spray stations, they may also include color change valves, solenoid valves, etc. The design of the outlet element of the spraying station is mainly based on the form of the circulation system, taking into account the pressure resistance, flow rate and the corrosion resistance of the material. For shear-sensitive materials, it is also necessary to consider the selection of low-shear elements. The spray station is usually set outside the spray booth, which can prevent the outlet components from being contaminated by paint, and is also convenient for disassembly, assembly and maintenance. Before the outlet component and before the position that needs to be disassembled, the valve should be installed, and the length of the hose should be appropriate. It is not good if it is too long or too short.