PRODUCT FEATURES
Union Flat Ptfe M/F — Product Features
ood & beverage equipment, water treatment, pharmaceutical piping, cooling & heating circuits, machinery process piping, marine plumbing, pump and valve connections, pipelines needing frequent disassembly.
Product Feature
Buyer Notes
Product Feature
EN 10204 3.1 material test certificate available for bulk orders. OEM marking is acceptable. Samples can be supplied for dimensional inspection and leak test before mass production. Please confirm thread type and size before order. Spare PTFE gaskets can be provided separately upon request.
OPERATING PRINCIPLE
How Union Flat Ptfe M/F Works
1. **M/F (Male × Female) Flat-Seat Union**: Features a male thread on one end and a female thread on the other, utilizing a PTFE (polytetrafluoroethylene) flat-gasket seal.
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2. **Three-Piece Construction**
Comprises two main body components and a hexagonal connecting nut, facilitating easy installation and disassembly.
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3. **Replaceable Pure PTFE Flat Gasket**
Offers exceptional chemical inertness and heat resistance; suitable for acids, alkalis, oils, and high-temperature media.
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4. **AISI 304 Stainless Steel**
Provides reliable rust resistance, making it suitable for use with fresh water, mildly corrosive media, and outdoor installations.
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5. **Precision-Machined Threads**
Available with BSPP, BSPT, or NPT thread options, compliant with ISO 7-1, DIN 2999, or ANSI B1.20.1 standards.
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6. **PN20 (150LB) Pressure Rating**
Manufactured in accordance with the ISO 4144 standard, ensuring stable sealing performance under rated operating pressures.
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7. **Pickled and Passivated Surface**
Features a clean surface with enhanced corrosion resistance; supports customized marking.
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8. **Comprehensive Size Range**
Available in a full range of sizes from 1/4″ to 2-1/2″ (DN8 to DN65).
ENGINEERING DATA
Technical Specifications
Technical data supplied for Union Flat PTFE M/F. Ratings and material combinations should be confirmed for the selected configuration.
| PARAMETER | SPECIFICATION |
|---|---|
| – Material | AISI 304 (1.4301 / ASTM A182 F304) |
| – Type | Union with flat-seat PTFE seal (male thread × female thread), including PTFE gasket |
| – Thread Standard | NPT (ANSI B1.20.1) / BSPT / BSPP (ISO 7/1, DIN 2999) |
| – Pressure Rating | PN16 (150LB, 20 bar) |
| – Standard | ISO 4144 |
| – Sealing | Flat PTFE gasket |
| – Surface Treatment | Pickled and passivated |
| – Operating Temperature | -20°C to +120°C |
MECHANICAL DIMENSIONS
Dimensions & drawings.
Compare connection size with the corresponding overall length, bore and handle clearance dimensions from the supplied drawing.
Dimension chart
| SIZE | L1 | L2 | D1 | D2 | D3 | D4 | D5 | H |
|---|---|---|---|---|---|---|---|---|
| 1/4″ | 9 | 9 | 12 | 12 | 11.5 | 13 | 17 | 44 |
| 3/8″ | 10 | 10 | 13 | 13 | 15 | 16 | 20 | 46 |
| 1/2″ | 10 | 10 | 15 | 15 | 18.5 | 20 | 24 | 53 |
| 3/4″ | 12 | 12 | 16 | 16 | 24 | 26 | 30 | 56 |
| 1″ | 14 | 14 | 17 | 17 | 30 | 32 | 37 | 62 |
| 1-1/4″ | 15 | 15 | 19 | 19 | 39 | 41 | 46 | 71 |
| 1-1/2″ | 17 | 17 | 22 | 22 | 45 | 47 | 52 | 74 |
| 2″ | 18 | 18 | 22 | 22 | 56 | 59 | 65 | 82 |
| 2-1/2″ | 20 | 20 | 25 | 25 | 72 | 75 | 80 | 93 |
Refer to the supplied dimension chart.
APPLICATIONS
Applications
Applicable media: the supplied document lists the following fluids. Actual compatibility depends on selected materials, concentration, temperature, pressure and the specific service conditions.
Application – Water Circulation
Cooling water, circulating water, drinking water and neutral purified water.
Application – Steam Piping
Clean, low-temperature saturated steam, subject to the product’s confirmed temperature and pressure limits.
Application – Compressed Air
Compressed air and nitrogen; verify compatibility for each system.
PURCHASING SUPPORT
Frequently Asked Questions
Find answers to common questions about sizing, materials, threaded connections and operating conditions.
1、What is Union Flat PTFE MF?
It is a 3-piece flat seat union. One end is **male external thread**, the other end is **female internal thread**. The sealing relies on compressing a PTFE gasket between two flat mating faces at the union centre, not metal taper seal. It allows easy disassembly for maintenance without cutting the pipeline.
Important distinction:
✅ Union Flat PTFE MF: Male × Female thread ends
✅ Union Flat PTFE FF: Female × Female thread ends
The flat seat gasket structure is identical, but the end thread configuration cannot be interchanged.
2、What thread standards are available?
Standard: **BSPP (G / ISO228-1 parallel thread)** for flat seat PTFE union. Optional BSPT (R/Rc) or NPT on request.
Threads are NOT interchangeable. Please confirm thread standard and size before order.
3、What stainless steel grades can you supply?
Standard grades:
– 304 / CF8 for water, air and general low-corrosion service
– 316 / 316L / CF8M for coastal, brine, chemical and chloride-containing media
4、What standard and pressure-temperature rating?
Manufactured to ISO4144, Class 150LB (PN20 / 300PSI).
PTFE gasket working range: **-20°C ~ +120°C**.
Pressure will derate when temperature rises. RPTFE gasket is available as an option for higher temperature service.
5、Manufacturing process: casting or bar stock machined?
Standard stock items: lost wax investment casting.
High-purity / high-precision requirement: solid bar CNC machined, higher cost.
7、Can you provide MTC material certificate?
Yes, EN10204 3.1 MTC with heat number is available. EN10204 3.2 third-party certificate can be arranged at buyer’s extra cost.
8、Surface finish options?
Standard: pickled matte finish.
9、Can you do laser marking?
Yes. We can mark size, grade, heat number, customer logo or brand on the flats.
10、Packaging for sea shipment?
Male threads are protected by plastic thread caps. Packed into export cartons, then loaded on fumigated wooden pallets with waterproof stretch film to avoid scratch and thread damage.
11、What is the lead time?
Typically, shipments are dispatched within 7–15 days of receiving the deposit, depending on the order quantity.
12、How is quality controlled?
Raw material inspection → CNC machining → Thread inspection → Hydrostatic testing → Visual inspection → Final dimensional verification before packaging.
13、Which Incoterms are available for overseas buyers?
We offer FOB (Free On Board) terms, with the shipment originating from a Chinese port. We will provide a commercial invoice, packing list, and bill of lading for import customs clearance.
14、Which Incoterms are available for buyers?
We offer FOB (Free On Board) or CIF (Cost, Insurance, and Freight) terms, with shipments originating from a Chinese port. We will provide a commercial invoice, packing list, and bill of lading for customs clearance.
15、What should be done if the threads are found to be defective or do not meet requirements upon arrival?
Please provide photos, videos, and inspection records. We will assess the root cause; depending on the contractual terms, solutions may include product replacement, a partial refund, or a reshipment.
Union Flat PTFE M/F
304 Stainless Steel Union Flat PTFE M/F, Flat Seat Male x Female Union with PTFE Gasket, PN16 150LB, ISO4144
3-piece flat face male × female union with replaceable PTFE flat gasket. Enables easy pipeline disassembly for maintenance. SS304 corrosion resistant for industrial process piping. MTC certificate available.
Type: Union Flat PTFE M/F
Material: 304/316L stainless steel
Nominal diameter: 1/4”–2-1/2” (D8–DN65)
Rated pressure: 150LB/3000LB
Connection type: Threaded connection (BSPT / BSPP / NPT)
