What is a metal diaphragm metering pump?
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The metering pumps I’m familiar with generally have plastic diaphragms, such as PTFE. But a couple of days ago I heard about metal diaphragms (such as 316L); aren’t the hardness and strength of metals higher than those of plastics? What are the advantages of him acting as a diaphragm? Please provide a more detailed introduction to reward_7ree
This post was last edited by To borrow the east wind on 2015-11-23 09:48. Most of those I’ve come across use metal diaphragms; PTFE, which is polytetrafluoroethylene, is used less often in this context. It mainly depends on the conveying medium to see if it is corrosive to the diaphragm. The diaphragms we use from Milton Roy are made of PTFE, while those from Pasfida are metal, those from Wanner are also metal, and those from Dalian Riva are metal as well. Brown Rupi is not clear; I haven’t used it. :):):)
It’s just a distinction between metal diaphragms and non-metallic diaphragms. Metal diaphragms are resistant to pressure, temperature, and corrosion, but they have a lower resistance to bending compared to PTFE.
The TEAL metering pumps used in PP projects are those with metal diaphragms. TEAL is a highly flammable substance (it can catch fire on contact with air). In the past, such pumps were always equipped with metal diaphragms in PP applications. There were concerns that TEAL might penetrate through PTFE and accumulate in the hydraulic section, posing a potential risk. However, later on, some major chemical engineering firms also began using PTFE-lined metal diaphragm pumps manufactured by companies such as Rivera and Mettler.
One version does not use metal as the diaphragm; there are also diaphragms made of white steel. On metering pumps with high outlet pressure. From both corrosion and economic perspectives, PTEF is the better choice.
Both PTFE and metal diaphragms (316L) are materials with good corrosion resistance; the use of diaphragms made from PTFE and 316L is closely related to the nature of the medium； Some of the clients I’ve worked with use metal diaphragms quite often; in my opinion, there isn’t much difference.
The ductility of PTFE diaphragms is greater than that of metals, which can lead to errors in measurements in high-pressure environments.
PTFE diaphragms generally can withstand temperatures below 150 degrees; at higher temperatures, metal diaphragms are required, as they can tolerate temperatures up to 200 degrees. Additionally, some materials can permeate PTFE, so metal diaphragms are also required
Materials such as composite materials, stainless steel, and alloys are chosen based on the specific requirements of each manufacturing process; each of them has its own advantages and disadvantages. Stainless steel diaphragms offer excellent corrosion resistance and wear resistance, and they are suitable for use with water-based coatings as well as viscous fluids~~
A flexibly designed metal diaphragm is used in place of a piston; driven by the driving mechanism, it performs reciprocating motion to complete the suction and discharge processes.
The swinging angle of metal diaphragms is generally only 1 degree, while PTFE can typically reach 12 degrees, and in some cases even 30 or 45 degrees. The advantages of metal diaphragm pumps, compared to PTFE diaphragm pumps, are their ability to withstand high pressures and high temperatures, as well as being less prone to leakage. The downside is that the pump head is large and heavy, and it’s expensive. Generally, additives are used in high-pressure oil wells, and as mentioned above, metal diaphragms are also typically chosen for Teal pumps.