使用EZ-Spray橡胶，避免昂贵的修复

概述


Overview
The EZ-Spray® Jr. System is ideal for a variety of mold making, spray casting and coating applications. To follow is a case history chronicling how a manufacturer of supermarket refrigeration units found EZ-Spray® Silicone 35 a relatively inexpensive answer to a potentially very expensive problem.

The manufacturer has many refrigeration units installed in supermarkets throughout the U.S., with the minimum cost of a unit at $20,000. The units keep fruit and other foods cold and fresh until sold. The galvanized steel plate bottom of each unit measures a minimum of 7' x 4' (2.13m x 1.22m), with many units being larger. These plates end up being a receptacle for water condensing from the refrigeration coils as well as a combination of food byproducts.

The Problem: 8 years following installation, the galvanized steel plate bottom of the unit rust has rusted. This is not something that the manufacturer had anticipated. Holes in the steel plate form, leaking water and other food byproducts onto supermarket floors. The rusty, oily mess created is a potential slipping hazard for customers

Supermarkets that bought these units are not happy and look to the manufacturer to replace them. Aside from the leaking problem, the coolers are still functioning normally, making replacing the entire unit a choice of last resort for the manufacturer. Replacing the galvanized steel bottom of each unit would mean time consuming disassembly of mechanical cooling components at expensive after-hours labor rates (any repairs would have to be done after 1:00am when customer traffic is low).

This led to thinking of how to turn to a coating of some kind that could seal the steel plate and stop the leaking while protecting the unit from further degradation. The manufacturer contacted Smooth-On for a material solution and we established the following criteria for selecting a coating:

It had to seal the plate and provide a barrier that withstood water and food byproducts for as long as possible.
The coating had to be safely applied in grocery stores in proximity to people and food.
Time spent repairing each unit had to be minimal, so the coating had to be fast curing so that the repair crew could be in and out of each store quickly.
After considering a variety of materials, EZ-Spray Silicone seemed to be the most promising candidate. The refrigerator manufacturer commissioned a laboratory to test the cured silicone for resistance to acids (citrus), animal fats, vegetable oils and other food byproducts at different temperatures. EZ-Spray Silicone showed no sign of degradation during prolonged exposure to these material variables.

As the step by step pictorial presentation chronicles, the EZ-Spray Silicone solution worked flawlessly.

Project Statistics

Total repair time including disassembly of the refrigeration unit, cleaning the metal plate, cutting and installing the pre-formed silicone sheet, applying EZ-Spray Silicone rubber and reassembly of the unit – 90 minutes.
Number of refrigeration units needing repair – over 1,200 units located at 280 stores.
Amount of EZ-Spray Silicone used to repair one refrigeration unit (including pre-formed sheet) – Just over 2 Cartridge Units or 6.5 lbs. (2.95 kgs.)
Repair personnel had nice things to say:

"Instead of requiring 5 guys working all night to replace the steel sheeting, the EZ-Spray System let us finish the job with 2 guys working 6 hours in each store. It's amazing, there is no smell or cloud to worry about. If the compressor did not make noise, customers wouldn't know that we were even there."

The manufacturer of the coolers calculates that using EZ-Spray Silicone to solve this problem saved them over 1 million dollars vs. the next least expensive repair alternative.

Materials Used in this Tutorial
Step 1: Preparing Model
The below pictures show the preparation of the refrigeration units for cleaning and application of EZ-Spray® Silicone rubber as a coating. The Galvanized steel has been subjected to years of acids and other food byproducts, causing the steel to rust, corrode, and leak.





Step 2: Dispensing and Curing of EZ-Spray Silicone
Once the steel has been thoroughly cleaned, pre-formed sheets of EZ-Spray® Silicone are cut to conform to all of the pipes and coils. Sil-poxy Silicone Adhesive is used to secure the EZ-Spray® Silicone to the steel base. EZ-Spray® Silicone is self leveling and uniformly coats the metal surface. Rubber is also used to encapsulate the pre-fomred silicone sheet. The spray tip allows precise delivery of the material into hard-to-reach areas. Once all of the surfaces are coated, a heat gun is used to reduce the cure time of the rubber.

The circulating fan is assembled and put in place before the food display shelf is replaced. 4 units done at this store... only 1,196 units left to go. Still, the EZ-Spray® rubber system remains the less expensive alternative to solving this problem by far.















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