In these uncertain economic times, getting the most for your money in industry is a top priority. Quality, reliability and durability are important to users as they focus on the lifetime costs of a pump rather than the initial price. A pump that is relatively inexpensive but breaks down after a short period of time will have to be replaced with a new one. Pumps that leak have unseen expenses in inventory loss, cost of labor and material in cleanup, not to mention the ever-present issue of compliance.
Compliance has become a priority for supplier and consumer in pump choice. Governments have created and will continue to create stringent standards for chemical use in production; violations can lead to heavy fines.
CorrosionPump components that do not stand up to chemicals can pose the problem of corrosion and leaching, which may affect not only the chemical being pumped, but also the integrity and ultimate success of the final product. According to www.corrosioncost. com, the annual cost of corrosion in the production and manufacturing category is $17.6 billion in the U.S. alone. One antidote is to replace metal components with polymers and composites because of their anti-corrosion properties. Corrosioncost.com states that, “The portion of polymers used for corrosion control is estimated at (only) $1.8 billion.” Ultimately, new synthetic pumps present manufacturers with the opportunity for increased productivity and cost savings.
ThermoplasticsPumps manufactured from carbon steel, stainless steel, nickel alloys and aluminum have long been the backbone of industry. Since the introduction of plastics in the late 19th century, and with each succeeding decade, developments in thermoplastics and thermosets have resulted in substantial improvements.
The advent of the semiconductor and computer industries in the 1960s opened the door for the extensive use of thermoplastics. Manufacturers of printed circuit boards found that even traces of metallic contamination, from using metallic pumps in production, could ruin the end product. Polypropylene (PP) pumps, which had better chemical compatibility than metal, delivered the fluids with no contaminants, making plastics and plastic pumps a mainstay of the manufacturing industry.
With each succeeding decade, extensive research brought improvements to old plastics and the development of new plastics. Today, PP, polyvinyl chloride (PVC), polyethylene, polyester, Teflon®, Kynar®, epoxy and Kevlar® are regularly used across all industries.
Plastic advantagesNow, pumps made from synthetic materials offer nearly all of the advantages of metal. Because plastics have more chemical compatibility than steel, manufacturers can use plastic pumps for a wider range of fluids and can expect them to last for long periods of time.
For example, polypropylene is light, but strong and durable, making it the most versatile of all the thermoplastics. It is impact resistant, it has a high melting point (327° F/164° C), it does not absorb water, it is highly resistant to aggressive chemicals, and it is significantly lower in price. The fact that thermoplastics can be heated and cooled many times without damage makes them ideal for recycling.
Polypropylene has the lowest environmental impact of any material, including both synthetic and traditional, because it is the easiest to reuse. While recycling thermoplastics is positive for the environment, it is also an opportunity for the manufacturer.
Weight is a major consideration. Polypropylene pumps are particularly lightweight, resulting in minimized packaging and reduced shipping costs. This source reduction also means that the manufacturer can put more content in each pump because the pump itself accounts for very little weight. In production, co-polymers can be coated without organic solvents or the evaporation of water, thereby reducing both energy requirements and emissions into the atmosphere.
Industries ranging from food and pharmaceutical production, to electronics manufacturing, require that many fluids be pure or ultra-pure to meet government regulations and manufacturing criteria. Contamination is a big issue. Many fluids will absorb moisture from the environment, making them corrosive toward vulnerable metals. While stainless steel is an excellent product for fluids transfer, oxidation of non-stainless can ruin the container of chemical. This oxidation can cause rusting in a nonstainless steel metal pump, and the eroded materials can flake into the fluid content and contaminate it and the end product. Even traces as small as 1 ppb in a fluid can ruin millions of dollars of electronic components if the fluid is contaminated. Food can be ruined by the look and taste of rust.
Due to their physical properties, thermoplastics and thermosets rarely leach contaminating extractables into fluids. Polypropylene, PVC and Kynar are very resistant to alkali materials, which makes them very useful with strong lyes, detergents and soaps.
GroundingIn addition to corrosive properties, liquid chemicals are often highly flammable, making the grounding of a pump extremely important. According to the National Fire Protection Association’s Recommended Practice on Static Electricity (NFPA 77), Paragraph 220.127.116.11: “To prevent the accumulation of static electricity in conductive equipment, the total resistance of the ground path to earth should be sufficient to dissipate charges that are otherwise likely to be present. A resistance of 1 megohm (106 ohms) or less is generally considered adequate.”
Until quite recently, only metal pumps could be effectively grounded to meet this standard. Now, however, pumps manufactured from conductive plastic can be grounded. This makes them as suitable and safe for use with Class 1 and Class 2 flammables as a metal pump, while also offering improved durability and chemical resistance.
With the proliferation of chemicals in manufacturing, safety and compliance have become priorities. Manufacturers who use chemicals need pumps that can handle the full range of process fluids. Pumps made of plastic offer a wider range of chemicalhandling options for less cost than their metal counterparts. Now, new conductive plastic pumps can increase those options to include handling flammable liquids safely and effectively.
In short, plastic pumps stand up to many aggressive chemicals and are more serviceable. They are designed to withstand corrosive atmospheres, have lower friction factors than metal and can better absorb the energy of impacting particles. While plastic components can be used to mitigate the effects of corrosion of a metal pump, a solid plastic pump needs no lining or protective coating, thereby eliminating the potential to peel, crack or abrade.