The efficient and clean application of chalk, talc, stearate or other powders to extruded materials has long challenged manufacturers. Many solutions have been developed – ranging from the simple open box with vibrator to the expensive electrostatic and recirculatory systems using compressed air, jets & filters.
Machines using vibrators are noisy and cause compacting of the powder, and the more expensive equipment requires continuous maintenance and will only operate if the chalk is absolutely dry.
The Marldon Chalker-4 is a compact, low cost and simple machine which solves all the above problems, and offers the following features:
- Will apply a wide range of powders
- Operates with powders of varying degrees of dryness
- Cable / hose passes through a dust cloud whose density can be varied
- Powder cannot become compacted
- No jets or pumps
- No atmosphere pollution other than chalk carried forward by the moving cable
- 220-240v single phase 50 Hz supply
- Replaceable seals and filters easily available from local suppliers
- Suitable for cables up to 50mm dia (optional 75mm).
- Supplied with adjustable height mobile trolley
- Left to right, or right to left operation
- Quiet reliable operation
The machine is of steel construction and comprises two chambers, in each of which is a rotating paddle. The paddles have variable speed control. A rectangular hopper positioned above the two chambers is hinged on both sides of its base allowing it to be opened from either side for initial threading of the cable through the machine. The cable path lies on the joint between the chambers and the hopper. A quantity of chalk is placed in the hopper and falls into the two chambers, where it is picked up and swirled into two contra-rotating circulating clouds through which the cable passes. The cable is shielded above to prevent chalk settling on the top of the cable.
The top of the hopper is fitted with a hinged cover for the purpose of placing chalk into the machine. This high filling point permits the addition of chalk while the machine is running without causing air pollution.
The entry and exit holes to the chalking chambers are filled with long haired wool which prevents the swirling chalk escaping into the atmosphere.
Beyond the exit from the powdering chambers is a long rectangular catch tray with a lower exit hole, beneath which is a removable collecting trough for excess chalk. The upper half of the catch tray is hinged along its length and can be opened while the machine is running if required, to enable chalk carryover to be scraped back into the collecting trough.
Mounted above the catch tray is a further hinged box with a small electric extractor fan and a disposable tissue filter. The end of this box is the point at which the cable leaves the machine and where the extractor fan draws up any fine particles of chalk which may still remain, preventing it escaping into the atmosphere.