1. General Introduction

• Application

Driven by media pump and compressed air, this machine specially designed for wet blast process can be utilized in the works as follows.

• Knock off oxide, remaining salt and welding slag from surface of castings, forgings, weldments and heat-treated parts. The process quality is up to Sa3 degree.
• Remove burrs and remainders from surface of machined parts.
• Improve surface roughness, the value of Ra.
• As a pre-treatment, active-surface will be obtained so to raise the adhesion to electro-plating or painting.
• Undertake the works that other process cannot do, such as smooth finishing the parts that are required for high precision and high smoothness or the parts that are shaped in grotesque.
• Improve physical and mechanical characteristics of part skin e.g. improving stress condition, bettering the coupling joining or lowering noise of working coupling.
• Renovate old machine parts.

• Range of Process

• Suitable for wet blasting process.
• Suitable for medium-small size parts in small batches.

• Feature

• With this machine, wet blast process makes no dust and keeps operator free from air pollution that endangers their health.
• For not specially requiring extra ventilator or dust remover or a workroom, this machine can be directly installed on products line so as to both save working area and facilitate parts flowing.
• With the features of flexible operating methods and technological parameters’ variety, this machine suits for the requirements of finishing processes for the parts made by different materials and the parts in various precisions.

• Being processed properly under reasonable parameters, the part surface quality will raise one lever higher than before.
• Wet blast process can harden part skin so to increase wear-resistance and fatigue strength.
•  Working circularly, media consumption is limited.
•  Main parts of the machine last long life and are easy to be maintained.

•   Outward Arrangement and Layout

• To mains Electrical supply
• To compressed air
• Filter regulator
• Solenoid
• To return hose from collector
• Door limit switch
• Roof lights
• Electrical box
• Oil fog lubricator
• To water pump
• To separator
• Media pump
• Liquid-in hose
• Separator
• Media Collector
• Left foot switch
• Middle foot switch
• Right foot switch
• Turntable
• Main body（Working Cabinet）
• Water return hoses（Flow back      hose）
• Media-in hoses

23.       Water supply

24.       To return hose from separator

Fig 1    Arrangement Drawing

Fig 2    Layout Diagram

1.5 Technical specification

1.5.1 Electric apparatus

• Media pump motor: Ac380V-50HZ, 4KW, 2840rpm.
• Separator motor: Ac380V-50HZ, 0.4KW, 2840rpm.
• Lighting: AC220V-50HZ, 3´ 20W.
• Voltage for control circuit: AC24V.
• Total consumption: app. 4.5KW

1.5.2 Sump volume: app.110L

1.5.3 Media:

• Media: Aluminum oxide (recommended) or others alike.
• Grade: 46#~180#.
• Quantity in circulation: app.20kg.

1.5.4 Turntable:

• Diameter: f700mm.
• Load (uniformly distributed): Max 100 Kg.

1.5.5 Process gun

• Quantity: One set hand-held gun.
• Media nozzle internal diameter: f12.5mm.
• Air jet internal diameter: f6.5mm.
• Air pressure (show on manometer when operating): 0.4~0.6Mpa.
• Air supply for single gun: app.1~1.5 m3.p.m (depended on working pressure).

1.5.6 Total air consumption: app.1~1.5 m3.p.m. (depended on   working pressure).

1.5.7 Air supply pipe: out-diameter f13mm, same as internal diameter of hose.

1.5.8 Water supply pipe: out-diameter f13mm, same as internal diameter of hose.

1.5.9 Weight with case: main unit app. 610Kg. accessories app. 210Kg.

1.5.10 Requirements

• Power: AC380V, 50HZ.
• Compressed air: Pressure 0.8~1Mpa, Flow at least 1.5cubic-M.p.m (on standard status of 20°C and 101.325 KPa).
• Water: Industrial tap water.

Note: Requirements above(1.5.10) should be meet by customer!

2. Operating Principles

As shown in fig 3, this machine consists of three separate but related units. They are main unit, grease dirt separator and media collector.

Knob

• Pneumatic wiper
• Wash hand valve
• Process gun
• Wash gun
• Workpiece
• Turntable
• Media level
• Media
• Bypass nozzle
• Media pump
• Overflow pipe
• Liquid-in hand valve（Normally closed，opend while collecting）
• Media return pipe
• Water supply
• Sump filling hand valve
• Overflow outlet
• Air supply
• Filter regulator
• Solenoid
• Wash nozzle
• Oil fog lubricator
• Liquid-out hose
• Liquid-in hose
• Inlet
• Outlet
• Vortex cone
• Pot
• Media-out hand valve
• Injection nozzle
• Drifting greasy dirt
• Dirt clearing funnel
• Bypass hose
• Injection hose
• Tank
• Draining pipe
• Draining valve
• Water pump

Fig 3     Service Line Diagram  

2.1 Main unit

As shown in the diagram at fig 3, the wet blast process, which completes a finishing treatment, is that the process gun driven by media pump and compressed air blasts mixed media liquid directly at the surface of work-piece so as to reach the requirement.

The media liquid (media for short) is a mixture of proper grade media and fresh water in which some corrosion inhibitor is added. Media and water should be mixed in certain ratio.

2.1.1 Circulation of Media  

As shown in fig 3, media in sump should be filled to the level of overflow outlet.

While media motor is running, the media is pumped to process gun, bypass nozzle and media collector. Inside process gun, media should meet compressed air. Driven by these two powers, media should be blasted through gun nozzle directly to work piece at high speed. Simultaneously a jet of media should come out through the bypass nozzle to agitate the media in sump for evenly keeping the ratio of the mixture that is being sucked into the pump.

Only when the collector is operating should the process media be allowed to go in the collector.  

Warning: Make quite sure that liquid-in ball valve to the collector is closed when starts the main unit.

2.1.2 Circulation of water

This machine would use industrial tap water. As shown in fig 3, water connected to cabinet goes in three ways. The first is to sump through filling valve. The second is to wash gun to clear processed component and cabinet interior after operation. And the third is to window wash nozzle of wiper, which would jet a water- curtain at window when wash valve is turned on.

2..3 Air circuit

Compressed air supply must be pre-installed for this machine. As shown in fig 3, connected into the machine, the air is divided in two ways. One is to the process gun. The other is to drive the wiper.

There are two process methods which customer selects according to the requirements. One method is called no-air process which media blasting is driven only by media pump. The other is that compressed air is simultaneously led to process gun for speeding up media blasting. Switching on or off the solenoid in air circuit would alter methods above.

Also, the window wiper is driven by compressed air. Operating a knob valve would start, adjust speed of or stop the wiper. Wiping frequency can be adjusted within a certain rang.

2.2 Media collector

This unit is for separating media from media liquid and collecting media. It works in two cases as bellow.

a.  To meet the process requirement of changing grade or sort of media or both, media in circulation must be taken out so that required one could be filled in. The collected media should be stored for further use.

b.  After long use, media was damaged to certain extent and can’t reach the process requirement. To renew media, collecting operation is a must. Collected medias would be gathered for further picking up.

As show in fig 3, liquid-in hose to the collector is connected to media pump. The liquid-out hose extends into the blast cabinet.

Warning:  Be sure that media pump is working when turn on liquid-in hand valve to start collector.

Turn on the liquid-in valve to collector, which is closed normally. Flows of media from pump would come to the vortex cone’s tangential inlet tube, which injects liquid into the cone at high speed. As a result of cone wall’s limit and the difference specific gravities between water and media, they separate. Under the centrifugal force the media that is heavier would spiral down along wall to cone’s bottom and drop into the pot.

Forming a cylinder around cone’s axis and on which exerted a lift, the water returns to cabinet sump via the outlet at cone top and delivery hose.

Switch off media pump after it has run for several minutes. Turn on the media-out valve of depositor to collect media slurry with a container. Most of working media could be collected in one time operation. After 2-3 cycles more than 90% of media would be collected. Only less in every nook and corner could be missed.

Warning: Turn off media-out valve before start media pump. Fix or hold process gun firmly while collector is working.

2.3 Greasy-dirt Separator

Separator matches main unit to clear away greasy dirt and feedback the media to sump. Feedback and clearing are done at same time as separator is working.  

Warning: Before start the separator, be sure that media pump was switched off.

See diagram at fig 3. Before start the separator, fill the separator tank with fresh water to the level of dirt-clearing funnel top.

During the separator operation, clear water is pumped to returning to cabinet sump through pipe so as to arise sump level rising. The greasy dirt drifting on media would then overflow into separator tank and some of them flow into the funnel.

Several minutes later, stop water-motor, turn on the grease draining hand valve under the separator to drain away the greasy dirt water, which had flown into the funnel.

When media pump works, as the bypass nozzle agitating media for keeping mixture ratio even in the upper level, some media carried by overflow water would go into separator from sump and deposit down to bottom of tank. The longer media pump works, the more the media loses from the sump. That would reduce the media concentration and would impair process quality.  So the separator should have the function to send the lost media feedback to the sump.

To solve the problem water pump, bypass hose and injector unit are designed. While liquid pumped into sump through delivery pipes from tank, the bypass water-jet keeps liquid in constant agitation to suspend the solid media so that it could be sucked, together with water, in the hose that deliveries liquid to tee joint and goes back to cabinet sump via tee joint to which the injection nozzle is connected. These construct a circulation of media feedback.

3.Electrical System

3.1 Mains supply

The required power supply is 380V, 50Hz, app.4.5 KW, and an earthed line. Customer should prepare a set isolator switch so that the power can be cut off in case the machine electrical system needs maintenance. Rightly fix input power lines to the terminal L1, L2, L3, N and PE.

Warning: Only specialist can do power connection.

3. Electrical circuit instruction