Mini diaphragm pumps transmit gas or liquid medium through the reciprocating motion of the diaphragm. These medium will come into contact with the mini diaphragm pumps head and diaphragm materials. The chemical composition, temperature and other physical and chemical properties of the medium may have an impact on the pump head and diaphragm. The pump head and diaphragm The material will also have a decisive impact on what kind of fluid medium the mini diaphragm pumps can transmit. This article sorts out the common pump head materials of mini diaphragm pumps and introduces the special characteristics of different mini diaphragm pumps head materials.
PA6/PA66 reinforced nylon
Nylon series products are widely used, covering almost every field, and are the most widely used varieties among the five major engineering plastics. Reinforced nylon is made by adding blending materials such as glass fiber and tougheners to nylon. With the increase of glass fiber content, the tensile strength and bending strength of the material are greatly improved, while the impact strength is more complicated. With the addition of toughening agent, the toughness of the material is greatly improved.
PA6 is also called nylon 6 (white). This material has the most superior comprehensive properties, including mechanical strength, stiffness, toughness, mechanical shock absorption and wear resistance. This, combined with good electrical insulation capabilities and chemical resistance, makes nylon 6 a “general-purpose” material used in the manufacture of mechanical structural parts and maintainable parts. PA66 is also called nylon 66 (cream color). Compared with nylon 6, PA66 has better mechanical strength, stiffness, heat resistance and wear resistance, and creep resistance, but its impact strength and mechanical shock absorption performance are reduced, making it very suitable for automatic Lathe machining.
1. Advantages of glass fiber reinforced nylon PA6/66
1) After adding glass fiber to nylon, the mechanical properties, heat resistance, dimensional stability, and aging resistance of the modified nylon are significantly improved, and the fatigue resistance strength is 2.5 times that of the unenhanced one.
2) Due to the addition of glass fiber, the mutual movement between the polymer chains of the plastic is restricted. Therefore, the shrinkage rate of the reinforced plastic is greatly reduced, that is, the shrinkage of the product is much better than before the addition of glass fiber, and the rigidity is also greatly improved.
3) Glass fiber reinforced nylon has a high softening point, low friction coefficient, wear resistance, self-lubrication, shock absorption, noise reduction, good electrical insulation, oil resistance, weak acid resistance, alkali resistance and general solvent resistance, self-extinguishing properties, and no Toxic, odorless and weather resistant.
4) After nylon is fiber reinforced, the water absorption rate of nylon slices can be reduced, allowing it to work in high temperature and high humidity environments.
Material Melting point Reinforced Melting point
PA6 230-280℃ 250-280℃
PA66 260-290℃ 275-280℃
2. Disadvantages of glass fiber reinforced nylon PA6/66
1) Toughness decreases and brittleness increases. This can be improved by adding tougheners.
2) Since the glass fiber will be oriented along the flow direction during the injection molding process, the mechanical properties and shrinkage rate will be enhanced in the orientation direction, causing the product to deform and warp.
3) During the injection molding process, glass fiber enters the surface of the plastic product, making the surface of the product very rough and speckled with defects such as floating fibers and material flowers.
4) The greater the proportion of glass fiber added, the greater the wear on the plasticizing components of the injection molding machine, mainly the wear of the screw.
5) Liquidity will decrease.
Most diaphragm air-liquid Mini diaphragm pumps produced by Hailin Technology use glass fiber reinforced PA6 as the material of the Mini diaphragm pumps head by default. It has good physical properties and good chemical resistance to most common media. When the chemical composition of the medium If it may react with PA6, you can choose a Mini diaphragm pumps head made of other materials to achieve chemical compatibility.
PTFE material for Mini diaphragm pumps
PTEE (Polytetrafluoroethylene, abbreviated as teflon) is generally called “non-stick coating” or “easy-to-clean material. This material is acid and alkali resistant, resistant to various organic solvents, and is almost insoluble in all solvents. .At the same time, PTFE has the characteristics of high temperature resistance and its friction coefficient is extremely low, so it can not only act as lubrication, but also become an ideal coating for easy cleaning of the inner layer of water pipes.
Features:
1. Heat resistance: operating temperature -40~260℃;
2. Corrosion resistance: resistant to strong acids, strong alkali and various organic solvents;
3. Hydrophobic: can be used to filter steam and various corrosive liquids;
4. Compared with PVDF, PTFE has a larger density, higher melting point, and is not easy to process, but its corrosion resistance is better.
As the plastic material with the strongest corrosion resistance at present, PTFE is widely used on the pump heads of gas-liquid Mini diaphragm pumps that transmit various corrosive medium. It can also be used as a diaphragm coating to enhance the corrosion resistance of the rubber diaphragm. When special media require the use of PTFE Mini diaphragm pumps head material, you can contact our company for customization.
PVDF material
PVDF polyvinylidene fluoride appears as translucent or white powder or particles. The molecular chains are tightly arranged and have strong hydrogen bonds. The oxygen index is 46%. It is non-flammable. The crystallinity is 65%~78% and the density is 1.77. ~1.80g/cm3, melting point is 172℃, heat distortion temperature is 112~145℃.
Features:
1. It has the characteristics of both fluororesin and general-purpose resin, and the long-term use temperature is -40~150℃;
2. It has good chemical corrosion resistance, high temperature resistance, oxidation resistance, weather resistance, and radiation resistance;
3. Has special properties such as piezoelectricity, dielectricity, and thermoelectricity;
4. In terms of application cost performance, PVDF is several times cheaper than PTFE.
5. Processing performance is better than PTFE
PTFE, as an engineering plastic material whose corrosion resistance is close to that of PTFE but has better processing performance, can be used as a corrosion-resistant Mini diaphragm pumps head substitute for PTFE to achieve better Mini diaphragm pumps head strength based on good corrosion resistance.
PPS material
PPS polyphenyl sulfide is a thermoplastic resin with phenylthio groups in the main chain of the molecule. It is a new type of high-performance thermoplastic resin with high mechanical strength, high temperature resistance, chemical resistance, flame retardancy, and good thermal stability. , excellent electrical properties and other advantages. It is widely used in the fields of electronics, automobiles, machinery and chemical industry.
Features:
1. Heat resistance: long-term use temperature can reach 260°C, and remains stable in air or nitrogen at 400°C;
2. Corrosion resistance: Corrosion resistance is close to tetrafluoroethylene, and chemical resistance is second only to PTFE material;
3. Excellent electrical properties, excellent mechanical properties, and good flame retardant properties;
4. It has average strength and good rigidity, but is brittle and prone to stress cracking. It is not resistant to benzene, gasoline and other organic solvents.
5. Through glass fiber reinforced modification, higher operating temperatures can be achieved and more toughness can be achieved. For engineering applications, glass fiber reinforced PPS is often used.
Most of the Mini diaphragm pumps produced by our company can select and customize the Mini diaphragm pumps head material to achieve medium compatibility with different temperatures and chemical compositions. For details, please consult our sales manager.