Thick Barrier Linings Flashcards
(45 cards)
Some thick barrier lining materials are:
- Reinforced plastic materials (such as fiberglass used in polyesters, final esters, epoxy, novolac epoxy, etc.)
-Polymeric sheet materials, including polyethylene - Rubber linings
What are the polymeric plastic sheet materials available?
- poly vinyl chloride (PVC)
- polyethylene (PE)
- polypropylene (PP)
- fluoropolymer materials
- Kynar PVDF
- Halar ETCFE
- Teflon FEP & PTFE
Rubber linings used for in the storage and transportation of:
Acids
certain alkalis,
food, chemicals, and food, products, selected solvent,
specialty chemicals and
other corrosive products, plastic pallets, clays, etc.
Rubber linings are used most commonly in:
Railroad tank cars
truck tanks
barge tanks
What are the two major classes of rubber linings?
Natural and synthetic
What is natural rubber lining?
Derived from latex obtained from Hevia trees and is coagulated with acetic or formic acid.
Unsaturated hydrocarbon known as polyisoprene
What is synthetic rubber lining?
Anyone of a group of man-made elastomers with one or more of the properties of natural rubber
How is rubber lining cured?
Vulcanization
What is vulcanization?
As psysiochemical change, resulting from the cross leaking of unsaturated, hydrocarbon chain of natural rubber with sulfur in the application of heat
What are the three factors that affect the properties of vulcanized product?
Percentage of sulfur and accelerated used, temperature of the curing process, time of cure
What are the cure methods used to vulcanized sheet rubber lining?
Autoclave, internal steam, atmospheric steam, hot water, chemical
Describe soft rubber lining
Greatest flexibility elongation in accommodation to movement of the three groups of rubber, good resistance to a number of corrosive chemicals, excellent abrasion resistance, good temperature resistance up to 140°F, standard for tanks containing hydrochloric acid
Describe try-ply linings
A try apply lining construction is used to form a sandwich which is semi hard, or hard, rubber between two layers of soft rubber
How are triply linings applied?
The steel substrate is coated with a special adhesive primer and then a tie gum (tacky layer of rubber) is applied over the primer to promote bonding of the two surfaces
Triply linings provide excellent corrosion and abrasion resistance. True or false.
True
Semi hard, rubber is compounded with what?
With about 15% by weight of sulfur
Semi hard, rubber linings can be used:
In strong acid concentrations
At temperatures up to 180°F
In water conditioning equipment
In wet chlorine gas
In plating solutions
What are the disadvantages of semi hard rubber linings?
Semi hard rubber compounds:
Are affected by temperature changes
Become very brittle at freezing temperatures
Are not suitable for wide temperature changes
What is an advantage of hard rubber lining?
Can handle highly corrosive solutions such as concentrated HCI and wet chlorine gas at 200 to 220°F
What are hard rubber linings generally used on?
Generally used used on rigid shapes of well-designed equipment that is not subject to rapid temperature changes
What are some characteristics of hard rubber linings?
Low permeability to moisture
Good ab abrasion resistance
Hardness range from 60 to 80 shore D durometer
What are some various types of synthetic rubber?
Butyl
Neoprene
Nitrile
Chlorobutyl
Hypalon
What does butyl rubber have? Excellent resistance to?
Sulfuric acid
Dilute nitric acid
Dilute Hydrofluoric at temperatures up to 200°F
