MIXER GEAR BOX

Mixers are optional on asphalt tanks and are used mainly for blending PMACs (polymer modified asphalt cement). Heatec currently uses Dodge gear boxes from Rockwell Automation.

The mixer has a gear box that is filled with lubricant. The lubricant should be periodically checked and replaced according to the manufacturers instructions.

A vent is shipped loose with each new mixer gear box. You should install the vent in place of the non-vented plug after the tank is erected and before the mixer is put into service (Fig. 19) . The vent prevents a build-up of pressure inside the gear box housing while the mixer is in operation.

Figure 19. Mixer gear box. Install vent when tank is erected. Remove it to add lubricant. Plug on side is used to check lubricant level.

The manufacturer of Dodge gear boxes currently recommends use of ISO 220 EP type mineral oil. The manufacturer recommends replacing it-depending on operating conditions- after 3 years of operation or 10,000 hours of operation whichever comes first.

The manufacturer provides other essential information about the gear box. This information is furnished with each new gear box. You should always follow the manufacturers recommendations, which are subject to change and may differ from the recommendations cited above. You may damage the bearings and gears inside the mixer gear box if you operate it without proper lubrication.

You should check the gear box for proper operation and lubrication at the start of the operating season and once a month during operation.

A plug is located in the housing of the gear box so that the level of lubricant in the gear box can be checked (Fig. 18). Do not check lubricant level while gear box is running. Remove this plug temporarily to make sure the level of lubricant is approximately the same height as the hole from which you removed the plug. If not, add lubricant until it begins to spill out of the hole. Be sure to replace the plug. When you check for proper lubrication you should also check mounting bolts of the mixer gear box to make sure they have not vibrated loose from operation.

To check for proper operation, open the manhole on top of the tank and operate the mixer. Visually observe that the shaft is rotating.

LUBRICATION

It is not unusual for plant operators to overlook the need to lubricate certain parts of an asphalt tank. Tanks have a number of parts that need lubrication. And their lubrication is very important.

Oil in the P-trap of the gauge board and lubricant in the mixer gear box have already been discussed. In addition to those parts, you especially need to lubricate hot oil valves and asphalt valves on the tank. Moreover, you should lubricate these valves on all the asphalt piping and hot oil piping. Be sure to apply some grease to the locking lever on the manhole-its hinges and its latch joints.

Some operators may not be aware that valves really do need to be lubricated and that they do indeed have lubrication fittings (Fig. 20). The fittings are button-head fittings and have flat ends, unlike conventional fittings that most everyone recognizes. The lubrication opening is often obscured by paint, which may be the reason they are commonly overlooked. Be sure to scrape the paint from the end of the fitting to ensure that your grease gun can easily inject the lubrication.

Figure 20. Resun valve with button-head fitting for lubrication. You may need to scrape paint from top of fitting to ensure that lubricant will be injected into body of valve.

R&M Energy Systems is the manufacturer of Resun valves used on Heatec products. They provide servicing instructions entitled Sealant Injection Equipment and Recommended Maintenance Procedures. These instructions can be downloaded from R&M Energy Systems. We normally provide a copy of these instructions with all Heatec products that use Resun valves.

You should follow Resun’s instructions for lubricating and maintaining valves on your Heatec products. They recommend a number of lubricants (sealants) suitable for various applications. Resun 101 and Resun 104 sealants (lubricants) are well-suited for valves on Heatec products.