Aggregate Industry Case Study: Tarmac, Hayes Asphalt Plant

“Since installing Expel approximately four months ago, they have not changed a single solenoid valve.”

Craig Bruce – Electrical Engineer – Tarmac

Tarmac’s Hayes Asphalt Plant has installed the best point-of-use filter available. Since installation, the site has drastically reduced site costs, downtime and maintenance.

Project Background

Tarmac’s Hayes Asphalt Plant has a unique setup. It has two asphalt plants at the same site. Over time, the asphalt plants have experienced continual expansion and are gradually merging. Due to this heavy reliance on compressed air, the plant operates two compressors and two refrigerant air dryers. In addition, the site also had several traditional compressed air filters installed throughout the plants to remove moisture. Despite installing conventional compressed air filters and refrigerant dryers, the site frequently had to replace solenoid valves due to moisture damage.

Solenoid valves are critical for almost every process across asphalt plants. For example, solenoid valves control the amount of each material going into the mixing area; they release specific quantities of material out of silos; they are used to blast compressed air through baghouse dust collectors. Moisture in compressed air lines causes solenoid valves to either malfunction or fail. Failing solenoid valves lead to extensive disruption to the asphalt manufacturing process. If a solenoid valve remains open or closed, it can cause incorrect quantities of a substance to be held or released. The only way to fix a moisture-damaged solenoid valve is to replace it entirely, resulting in avoidable part replacement costs, production downtime and product wastage.


Why did Tarmac choose Expel?


The refrigerant dryers and conventional compressed air filters the site had installed could not solve the moisture problem. Expel is a far more reliable way of protecting pneumatic equipment as it guarantees all liquid water, oil emulsion fluids, and solid particulates down to 1 micron from a compressed air line. The fact that Expel can always ensure such high-performance levels separates it from any other compressed air filtration methods currently available on the global market. 

The benefits of installing Expel at the site were almost instantaneous. The site’s Electrical Engineer was astonished that Expel had eradicated the problem. He reported that the maintenance team has not had to replace any solenoid valves since installing Expel. He also stated that the team put the efficiency and effectiveness of the Expel units to the ultimate test when the refrigerant air dryer broke down. Despite moisture and condensation being even more prevalent in the compressed air lines, Expel removed all condensation without a refrigerant dryer. When the dryers had failed previously, the traditional filters would quickly become overwhelmed with moisture. In radical contrast, Expel provided superior equipment protection by continually ensuring there was never enough moisture present to cause damage.

It was clear to the team that they had sought the best point-of-use filter available on the global market.


Reduced maintenance

Reduces Costs

Reduced downtime

Reduced energy usage


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