Auto DI-Water Drip System

De-ionized Water Drip System for Investment Casting

Overview

In the process of Investment Casting, there are slurries that are used to create the molds for the parts. Like many slurries, there is a consistency where it flows the best. Furthermore, there will be a gradual reduction in the water concentration in the slurry due to use or evaporation. In the past, PCC Structurals would periodically add deionized water to the slurry pots. Which then would result in the slurry pot being unusable due to the pot needing to homogenize. In order to increase the volume of the parts that could be produced and to extend the life of the slurry pot, PCC Structurals requires a method of maintaining the optimal viscosity.

Requirements

• Modular system

• 4-20mA PLC Communication

• Low flowrate pump

• Deionized water compatible

Design

First, the selection of the pump would be the most critical part as it controls the flow rate, is deionized water compatible, and low enough flow rate to not flood the slurry. If any of these requirements were not met, the project would not work.

Next, I needed to find a reservoir that would be airtight, small, and wall-mounted. Airtight so that the deionized water would not turn into regular water from the free molecules in the air. Small to be modular and to keep a fresh supply of deionized water. Wall mounted because the pump is not self-priming and requires to be gravity fed. Furthermore, it would be the best for small footprint and modular packaging.

Afterward, I needed a way for the deionized water to be refilled automatically. This is the case because we cannot just have the pump drawing water straight from the deionized water maker. The pressure would be too high. The solution I came up with was an ultrasonic sensor that would be mounted at the top of the reservoir. The sensor would trigger a Pneumatic Actuated valve to open up and fill the reservoir with fresh deionized water.

Results

The implementation of the Auto Drip system when tied together with their small-scale viscosity measuring station increased the useable lifespan of the slurry pots and increased the uptime on the slurries. Additionally, making the system modular allowed for the implementation into all the PCC Facilities to save even more money across the corporation.