Category: Corrosion

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Case Study: Reinforcement of Weakened 22 Degree Cast Iron Pipe Elbows

Reinforcement of 22 degree elbows on cast iron water mains carried out by Sylmasta

Ending a potentially explosive situation – Sylmasta provide reinforcement for pipe elbows following a blowout in a valve chamber

A blowout in a valve chamber in Grimsby, United Kingdom, alerted a water company to the fact that numerous 22 degree 450mm cast iron pipe elbows were below specification and required urgent reinforcement to prevent further incidents occurring.

Case Study Data

Site
Valve Chamber
Location
Grimsby, United Kingdom
Repair Type
Elbow joint reinforcement
Defect
Below specification 22 degree elbow joints on 450mm cast iron water mains

Products Used

Liquid Metal Epoxy Coating
Offered protection to the pipework from factors such as corrosion and created a PCC-2 compliant load transfer layer with SylWrap HD.

SylWrap HD Pipe Repair Bandage
10 layer application reinforced each elbow joint by providing an impact-resistant protective sleeve.

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Case Study Details

Numerous large diameter water mains made from cast iron were operated by the water company with most of these approximately 50 years old.

After an incident in a valve chamber in Grimsby where a 22 degree bend on a 450mm main blew apart, analysis of the cast iron showed that the original castings were below specification.

The incident was believed to have occurred when the water main pump from the reservoir to the treatment works stopped and the non-return valve closed, causing a pressure surge which peaked at 10 bar from zero.

Analysis of the cast iron pieces showed no corrosion along the crack lines. The blowout was therefore most likely caused by the low strength of the original casting which had a hardness of only 107.

To prevent similar incidents occurring again, the water company needed to carry out reinforcement of all remaining pipe elbows of the same specification.

  • Pipework in a valve chamber where Sylmasta carried out the reinforcement of 22 degree cast iron pipe elbows
Pipework in the Grimsby valve chamber

The length of the repair area was 350mm between flanges and the application needed to withstand 8 bar operating pressure with fluctuations up to the 10 bar which had caused the original blowout.

Sylmasta advised using Liquid Metal Epoxy Coating and SylWrap HD Pipe Repair Bandage to strengthen the elbow joints against future pressure surges and other factors including corrosion.

Each pipe was cleaned prior to being coated with Liquid Metal, a metal-filled brushable epoxy which sets to a smooth, metallic, hard-wearing surface over pipework.

Coating the elbow joints with Liquid Metal provided corrosion protection and improved adhesion between the pipework and the SylWrap HD Bandage, creating a PCC-2 compliant load-transfer layer.

10 layers of SylWrap HD were then applied over the Liquid Metal. SylWrap HD is a composite repair wrap with a water-activated resin which sets rock hard in minutes, providing reinforcement to pipework pressure resistant to 30bar.

  • Reinforcement of elbow joints in a valve chamber made using Liquid Metal Epoxy Coating and SylWrap HD Pipe Repair Bandage

Each elbow joint could be reinforced in two to three hours and there was no need to turn off the water supply to complete an application. Sylmasta’s repair saved the water company considerable money compared to replacing the below specification pipework and the necessary shutdown of equipment.

After the repair, the strategic water operations manager told Sylmasta: “The wrapping materials have proved central to our project in securing the structural condition of some 22 degree bends found to be in weak condition.”

“The early success of the project in Grimsby has seen it already adopted by other sites in our network, with Hartlepool also happy with it as a preventative measure and more to follow.”

If you have an application you would like to enquire about, then please get in touch

Call: +44 (0)1444 831 459
Email: sales@sylmasta.com

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Case Study: Repair of Metal Blades in Bakery Flour Mixers Suffering From Heavy Corrosion

Metal blades in a bakery flour mixer were suffering from corrosion until Sylmasta Ceramic Brushable Green provided a repair

Saving a bakery a load of dough – Sylmasta repair metal blades suffering from heavy corrosion in a flour mixer

When metal blades in two flour mixers were found to be suffering from corrosion, a commercial bakery in Puerto Rico was faced with the prospect of a costly shutdown – until a Sylmasta repair saved the bakery a load of dough in more ways than one.

Case Study Data

Site
Commercial Bakery
Location
Puerto Rico
Repair Type
Corrosion protection and repair
Defect
Heavily corroded metal blades in two flour mixers

Products Used

Ceramic Brushable Green
Brushable epoxy coating refurbished the corroded blades and provided future protection from both corrosion and abrasion

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Case Study Review

The mixers in question were used by the bakery to mix together flour and other ingredients to make turnovers and other popular products.

During a regular inspection to the machinery, it was discovered that the blades were suffering from corrosion. Production using the two mixers in question had to be halted until the parts were either replaced or underwent repair.

A flour mixer in a bakery in Puerto Rico which was suffering from badly corroded interior blades
One of the flour mixers suffering from corrosion

New blades for the flour mixer would have cost $3000 per blade, setting the bakery back $6000 on new parts for both machines plus installation costs. There were further complications when it was revealed that replacement blades were not available from stock.

This meant that the parts would have to be built from scratch, a time consuming process that would have meant a long wait for the mixers to be put back into operation. With the two mixers out of use for the foreseeable future, the bakery would have found itself struggling to fulfil existing orders, let alone take new ones.

An old and worn flour mixer in a bakery required protection and repair from corrosion
Wear and tear had taken its toll on the flour mixers

$6,000 to replace the metal blades suffering from corrosion and many weeks of lost production. The bakery was looking at losing a lot of dough, both in terms of money and the delicious baked goods that it made.

A better solution than replacing the blades was needed and the bakery started looking for repair methods. That led them to Sylmasta, who were able to recommend the use of Sylmasta Ceramic Brushable Green for the job.

Sylmasta Ceramic Brushable Green epoxy coating used to repair and refurbish metal blades in a flour mixer which were suffering from heavy corrosion
The repaired metal blades inside the flour mixer coated with Ceramic Brushable Green

Ceramic Brushable Green is a toughened, solvent-free, water-resistant coating that is used to reinforce and strengthen machine parts. It offers protection against corrosion and its ultra smooth, low friction finish reduces abrasion.

Coating the blades with Ceramic Brushable Green therefore not only allowed the flour mixer to be put back into service, but it lengthened the lifespan of the parts by making them less susceptible to wear and tear.

An epoxy repair coating used to protect metal machine parts from corrosion
Ceramic Brushable Green will protect the blades from corrosion and abrasion

The ease with which Ceramic Brushable Green is used enabled the bakery to carry out a quick and easy repair. It is brush applied and simply painted onto the area requiring repair.

Several coats were used and within 24 hours of the application, both the flour mixers in question were put back into operation and the bakery was operating at full capacity once again.

After completing the repair, the bakery contacted Sylmasta to say how happy they were with the solution and that the blades now looked as if they were brand new.

Ceramic Brushable Green is reinforced with hard-wearing, high purity, green silicon-carbide, which means it will be a long time before the blades require servicing again.

If you have an application you would like to enquire about, then please get in touch

Call: +44 (0)1444 831 459
Email: contact@sylmasta.com