Solving Problems with Precoat Metals

Precoat Metals, Houston, Tx, a supplier of coated roll steel, operates an SGH-PY200 in the waste treatment plant. In 1990, the maintenance manager contacted our office about a pump for lime slurry.

Lime slurry is injected into the waste treater as a neutralizer. Operating in this service was a progressing cavity type pump running at 1725 rpm. Lime slurry was continuously circulated in a loop. When the pH monitor registered a low pH condition, a solenoid actuated valve opened allowing the circulating lime slurry into the tank adjusting the pH.

Their on-going problems were, rapid wear of the pump stator and seal and malfunctioning of the valve, often coated open with thickened lime slurry. Precoat’s home office Engineering Department strongly suggested installing an expensive diaphragm/ball/check type metering pump to solve this problem.

Instead, the maintenance department purchased a Vanton Flex-I-Liner Pump (CC­PY30AM with Neoprene liner). The pump was installed over the lime slurry mix tank. The new pH adjust system now operates in this manner. The pH-probe 4-20 ml signal opens a pneumatic valve which starts the Pumps· air motor. Following the signal, the pump operates only until the pH is adjusted.

Previous experience of pumping lime slurry in the Houston area had yielded a body block life of four years and liner life of twelve months.

The Precoat pump has operated for the past 60 days without a hitch. A second model 30, has been purchased to move domestic waste. The $5,000.00 metering pump was purchased by the Engineering Department. It sets idol in the Houston plant. After hearing the good news, a sister plant also purchased a CC-30 for its pH adjust tank.