Where is PTFE mainly used for spraying on diaphragm cylinders of petroleum machinery

Source：www.dqig.cn Release date： 2025年07月21日

Information summary：In petroleum machinery, diaphragm cylinders (hydraulic/pneumatic actuators that separate the medium from the driving components through diaphragm plates) are sprayed with polytetrafluoroethylene (PTFE, commonly known as "Teflon"), mainly utilizing its strong corrosion resistance, low friction coefficient, excellent non stick performance, and high and low temperature resistance (-200 ℃~260 ℃) to so

In petroleum machinery, diaphragm cylinders (hydraulic/pneumatic actuators that separate the medium from the driving components through diaphragm plates) are sprayed with polytetrafluoroethylene (PTFE, commonly known as "Teflon"), mainly utilizing its strong corrosion resistance, low friction coefficient, excellent non stick performance, and high and low temperature resistance (-200 ℃~260 ℃) to solve problems such as corrosion, wear, and medium adhesion in petroleum extraction, transportation, and equipment operation. The specific application scenarios are as follows:
1、 Diaphragm cylinder in drilling and completion equipment
During the process of oil drilling, diaphragm cylinders are often used to control the transportation, pressure regulation, or wellhead equipment movement of drilling fluids (mud). Spraying PTFE can cope with extreme working conditions:
Drilling fluid control diaphragm cylinder
Drilling fluid contains a large amount of clay particles, chemical additives (such as salts and acids), and rock debris, which have strong corrosiveness and abrasiveness. Diaphragm cylinders used to regulate drilling fluid flow and pressure (such as auxiliary diaphragm control cylinders for slurry pumps), with PTFE sprayed on the inner wall of the cylinder and piston surface:
Can resist corrosive gases such as H ? S and CO ? in drilling fluid, as well as salt spray erosion, to prevent seal failure caused by cylinder rusting;
Reduce the frictional resistance between the piston and cylinder, minimize wear caused by particles in the drilling fluid, and extend equipment life (especially effective in deep wells and high-temperature and high-pressure wells).
Wellhead preventer diaphragm cylinder
Blowout preventer is a key equipment to prevent blowouts during drilling, and its action (such as gate switch) is often driven by hydraulic diaphragm cylinder. There are leaks of crude oil and drilling fluid, as well as erosion from seawater (offshore drilling platforms) in the wellhead environment. PTFE coating can protect the cylinder body from these media corrosion, while ensuring smooth operation of the diaphragm cylinder under high pressure (usually above 30MPa), avoiding the failure of the blowout preventer due to corrosion and jamming.
2、 Diaphragm cylinder in oil extraction and well repair equipment
During the oil extraction process, diaphragm cylinders are used to control pumping equipment, wellhead valves, etc. PTFE coating mainly solves the corrosion and adhesion problems of crude oil media:
Diaphragm driven cylinder of pumping unit
Some new pumping units use diaphragm cylinders instead of traditional hydraulic cylinders to drive the pumping rod, and their working medium may be mixed with crude oil and formation water (containing high concentrations of salts and sulfides). PTFE coating can prevent the inner wall of the cylinder from being corroded by formation water, while also avoiding the adhesion of gum and asphalt in crude oil to the surface of the cylinder body, reducing piston blockage caused by fouling, and lowering the frequency of well repairs.
Diaphragm cylinder for well repair operation
During the well repair process, power equipment used for lifting and lowering oil pipes and casings (such as clamping devices and hydraulic jacks on workover rigs) are often equipped with diaphragm cylinders. These devices need to come into contact with crude oil, sulfur-containing wastewater, and well repair fluids. The chemical resistance of PTFE can protect the cylinder body, while the low friction characteristics ensure that the diaphragm cylinder operates correctly during frequent starts and stops, improving well repair efficiency.
3、 Diaphragm cylinder in oil and gas transportation and processing equipment
In the process of oil and gas gathering, separation, and processing, diaphragm cylinders are used to control pipeline valves, separator components, etc. PTFE coatings are used to prevent corrosion from mixed media:
Oil pipeline valve control diaphragm cylinder
The cut-off valve and regulating valve of long-distance oil and gas pipelines are driven by diaphragm cylinders, and the medium inside the pipeline may contain crude oil, natural gas, water, and trace amounts of H ? S and CO ? (acidic gas). PTFE coating can resist corrosion from acidic media, ensuring long-term stable operation of the cylinder body and avoiding the risk of oil and gas leakage caused by valve control failure.
Diaphragm cylinder of oil and gas separator
In the oil and gas separator, the diaphragm cylinder used to adjust the separation baffle and liquid level control needs to come into contact with media such as oily wastewater and light hydrocarbons. The non stickiness of PTFE can prevent crude oil and oil stains from depositing on the surface of the cylinder body, reducing cleaning and maintenance costs; At the same time, its temperature resistance can adapt to the high temperature environment inside the separator (some working conditions can reach 150 ℃ or above).
4、 Diaphragm cylinder in offshore oil equipment
The equipment of offshore oil platforms faces strong corrosive environments such as salt spray, seawater immersion, and high humidity. PTFE coating is a key protective measure for diaphragm cylinders:
Hydraulic diaphragm cylinder for offshore drilling platform
The driving diaphragm cylinders of the lifting system, anchoring equipment, pipeline valves, etc. on the platform are exposed to salt spray for a long time and may be soaked by seawater splashes. PTFE coating (usually combined with sandblasting pretreatment and primer) can form a dense anti-corrosion layer, preventing chloride ions from penetrating and corroding the metal substrate of the cylinder body (such as carbon steel and alloy steel), ensuring the service life of the equipment in marine environments (generally requiring no major repairs for more than 5 years).
Underwater oil tree diaphragm actuator cylinder
The valve control of deep-sea oil trees (underwater wellhead equipment) relies on underwater diaphragm cylinders, and the working environment is high pressure (water depth exceeding 100MPa), low temperature (4-10 ℃), and seawater corrosion. PTFE coating is not only resistant to seawater corrosion, but also maintains good flexibility at low temperatures, avoiding coating embrittlement and peeling, ensuring reliable operation of diaphragm cylinders in extreme underwater environments.

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