Selection Guide for Different Materials of Micro Diaphragm Pump Head

When the micro diaphragm pump transmits fluid media through the reciprocating movement of the diaphragm, these media will come into direct contact with the pump head and membrane.The chemical composition, temperature, other physical and chemical properties of the fluid medium may affect the pump head and diaphragm. The material of the pump head and diaphragm also has a decisive influence on what fluid medium the pump can transfer.

What are the characteristics of pump heads made of different materials? What gases and liquids are suitable for transmission? This article will explain these problems in detail, hope it can provide you with reference when selecting models.


1.PA66 material
PA66,also name nylon 66, is polyhexamethylene adipate, which is a translucent or opaque milky white crystalline polymer with plasticity. The material has the most superior combination of properties, including mechanical strength, stiffness, heat resistance and abrasion resistance, coupled with good electrical insulation and chemical resistance, making it a "universal grade" material. Most TOPSFLO micro diaphragm pumps use PA66 as the material of the pump head.

PA66 main features:
A. Excellent mechanical properties, with high mechanical strength and good toughness.
B. Good self-lubrication and small friction coefficient, so it has a long service life as a transmission part.
C. Excellent heat resistance. After glass fiber reinforcement, PA66 can be used for a long time at 150°C, and its heat distortion temperature can reach above 250°C.
D. Excellent electrical insulation properties, with high volume resistance and high breakdown voltage, making it an excellent electrical and electrical insulating material.
E. It is resistant to acids, alkalis, most inorganic salt solutions, halogenated alkanes, hydrocarbons, esters, ketones, etc., but is easily compatible with polar solvents such as phenol and formic acid.
Suitable liquid or gas type of PA66:
Liquid: light acid, light alkali and neutral liquid, such as gasoline, lubricating oil, ethanol, methanol, acetic acid, acetone, etc. Some aqueous solutions, such as ammonia, nitric acid, sodium hydroxide, etc.
Gas: air, nitrogen, hydrogen and other inert gases. Certain industrial gases, such as methane, ethylene, acetylene, chlorine, etc.

2.PP Material
The name of PP is Polypropylen. It is a non-toxic, odorless, tasteless milky white high-crystallization polymer. TOPSFLO can provide customized solutions for PP pump heads according to the specific needs of customers.

The main features of PP are as follows:
A. Physical properties: Odorless, tasteless, non-toxic. It is the lightest of the commonly used resins.
B. Mechanical properties: Excellent mechanical properties, including tensile strength, compressive strength and hardness, outstanding rigidity and bending fatigue resistance, and poor impact strength at low temperatures.
C. Thermal properties: It has good heat resistance, the product can be sterilized at temperature above 100°C, and it will not deform at 150°C under the condition of no external force. Embrittlement will occur below -35°C, and its cold resistance is not as good as PE.
D. Chemical stability: Good chemical stability. It does not interact with most chemicals except strong oxidants. water resistance is particularly good.
E. Electrical properties: Good electrical insulation resistance to high frequency, and also has good electrical insulation in humid environments.

The type of liquid or gas suitable for PP material:
Liquid: acidic liquid, such as sulfuric acid, hydrochloric acid, hydrofluoric acid, etc. Weak alkaline liquid, such as ammonia water, ethanolamine, etc. Some organic solvents, such as acetone, formaldehyde, etc. Drinking water, pure water, etc.
Gas: air, nitrogen, hydrogen and other inert gases. Chlorine, ammonia and other active gases.

3.PPS material
PPS is a new type of high performance thermoplastic resin with a white, hard, polymer-like physical appearance. Topsflo can provide customized PPS pump head solutions according to customers' specific needs.

The main features of PPS are as follows:
A. Heat resistance: It has excellent heat resistance, its continuous use temperature is up to 220-240°C, and its heat distortion temperature under a load of 1.82MPa is above 260°C.
B. Flame retardant: It has very good flame retardancy, and can reach UL94-VO and 5-V grade (no dripping) without adding any flame retardant, and the smoke emission during combustion is very low.
C. Chemical resistance: Excellent chemical resistance, insoluble in any organic solvent below 200 ℃ (except strong oxidizing acid), and stable to various radiations.
D. Dimensional stability: After compounding, PPS resin has extremely small molding shrinkage, low water absorption, small linear expansion, also show excellent dimensional stability even at high temperatures or high humidity conditions.
E. Electrical properties: Electrical insulation and dielectric strength is good, no much change even at high temperatures, high humidity and high-frequency conditions.

The type of liquid or gas suitable for PPS material:
Liquid: some organic solvents, such as benzene, toluene, xylene, acetone, etc. Weakly acidic and neutral liquids, such as nitric acid, acetic acid, ethanol, water, etc.
Gas: High temperature gas, such as automobile exhaust, smoke, etc. Some industrial gases, such as methane, chlorine, ammonia, etc.
Under some extreme conditions, the performance of PPS materials may change and specific experimental tests are required.

Pump head selection case reference for micro diaphragm pump :

Case Reference	Liquid Type	Product Solution	Product Photo
Customer A	Corrosive materials: 16% blend of chlorine, phosphoric acid and oxalic acid	TF30-A24-A01 Pump Head：PP Material Rated Voltage：24V Max flow rate：0.4L/min

It is worth noting that for some special environments such as strong acids, strong alkalis, and strong oxidants, various materials may not be suitable. The specific situation needs to be considered comprehensively according to the chemical properties of the material and the liquid or gas.

TOPSFLO can select and customize the material of the pump head of the micro-diaphragm pump to achieve compatibility with media of different temperatures and chemical compositions. If you want to know more about pump solutions, pls feel free to consult TOPSFLO pre-sales engineers.