BSP Female Flat Seat Fitting: 22211 Series

Why This BSP Female Flat Seat Fitting Passes the Compliance Gate

A BSP female flat seat fitting joins a braided hydraulic hose to a BSPP flat seat connection: a swivel nut with an internal parallel G thread draws a flat sealing face onto the flat seat of the mating stud, and a soft seal element between the two faces does the sealing. The 22211 series from HENGHUA covers 18 part numbers from -04 to -32 with G-series parallel threads from G1/4″ to G2″. Every unit is cold-forged from carbon steel, heat-treated, plated, and 100% pressure tested before shipment. For OEM buyers this fitting is a compliance gate; for maintenance teams it is the flat seat BSP termination that seals with a replaceable washer or O-ring, which keeps service cost low on equipment with many BSP connections.

• Flat seat sealing: the fitting’s flat sealing face compresses a soft seal element (bonded washer or O-ring, confirmed at order) against the flat seat face of the mating male stud. The seal element is a wear part that is replaced in service, not machined away.
• BSPP G thread: the thread is parallel (G series, ISO 228-1) and only holds the connection; the flat faces and the seal element do the sealing. G threads must never be interchanged with BSPT taper threads, which seal by thread interference.
• Swivel nut design: the drawing shows a single hexagon, S2, on the swivel nut; the nut is captive on the body and rotates freely, so the hose can be oriented before final torque and is never twisted by the connection.
• Braided hose executions: the part numbers in the table are for braided hose from -04 to -32; for spiral hose, change the series number to 22212 per the factory sheet.
• OEM gate check: full dimensional and material conformance with G thread form per ISO 228-1, with material test reports (MTR) available for every batch.

Core Advantages

1. Low-cost service seals: the flat seat seals on a replaceable washer or O-ring, so a leaking joint is fixed by changing the seal element, not the fitting.
2. Swivel nut, no hose twist: the nut turns independently on the body, so the hose keeps its natural lay and the assembly is not wound up when you tighten the connection.
3. Eighteen sizes, G1/4″ to G2″: the straight flat seat line covers small instrumentation lines up to main return lines, with T and W tail variants for different hose constructions.
4. Established BSP practice: the flat seat with soft seal element is one of the most common BSPP connection styles in European-style hydraulic equipment, so matching seal elements are available worldwide.
5. 96 to 1000 h salt spray options: trivalent zinc (96 h), zinc-nickel (720 h), or Dacromet (1000 h), matched to your environment.

Technical Specifications

What Is This BSP Female Flat Seat Fitting?

This BSP female flat seat fitting terminates a braided hose with the BSPP flat seat connection. The port end is a swivel nut carrying a parallel G thread (G series, thread form per ISO 228-1). Behind the thread, the fitting presents a flat, machined sealing face. When the nut is tightened onto a male G-threaded stud whose end face is also flat, a soft seal element between the two faces is compressed and forms the seal. The G thread is parallel and does not seal by interference; it only pulls the faces together. This is why a flat seat connection must never be paired with a BSPT taper thread, which seals by thread interference instead.

The flat seat system is the soft-seal cousin of the 60° cone system used across the same BSP hardware. In the 60° cone version, two machined cone faces meet metal-to-metal, or an O-ring on the cone does the sealing. In the flat seat version, the sealing element sits between two flat faces, which makes the joint forgiving on the seat face condition and keeps the service part cheap: when the joint weeps, you change the washer or O-ring rather than reworking any metal. The seal element is normally a bonded washer or an O-ring sized to the seat; HENGHUA confirms the seal type and compound for your fluid and temperature at order, and the element can be supplied with the fitting.

The 22211 is the straight member of the BSP flat seat hose fitting family, complementing the 22241 (45°) and 22291 (90°) elbows on the same sealing geometry. The series covers 18 sizes from -04 to -32; the part numbers in the table are for braided hose, and for spiral hose the series number changes to 22212. Rows marked T and W carry tail-profile variants for different hose constructions; keep the suffix in the part number when ordering.

Dimensional Data and Threads

Full dimension drawings with A, C, and S2 callouts are supplied as PDF and CAD (STEP/DWG) files. Because this is a crimp fitting, the two process-critical parameters are the hose insert depth and the crimp outside diameter; both are hose-series specific and are listed in the crimp data sheet that accompanies every order.

Full Dimension Table (Part Number Matrix) {#by-thread-size}

Read the table with your BSPP thread (E) and your hose size (dash). The part number is the order code; copy it directly into your inquiry or purchase order. The pattern is 22211-[thread dash]-[hose dash]: for example, 22211-12-12 has a G3/4″ thread and suits a -12 (20 mm) braided hose.

The part numbers shown are for the braided-hose version. For spiral hose, change the series number to 22212, whose stem is longer for the extra reinforcement layers.

Select by Hose Dash Size {#by-hose-size}

Match your hose bore first, then read the thread sizes available for that bore:

Material and Heat Treatment

Cold forging preserves the grain flow of the steel, which raises fatigue resistance under pressure pulsation. Each heat-treatment batch is hardness-tested and recorded, so the hardness number on the MTR matches the parts you receive.

Working Pressure

The exact rating for your part number, seal element, and hose combination is confirmed on the datasheet and by our engineers before shipment.

Pressure-Temperature Operating Envelope

The steel body and flat face hold their strength across the full temperature window, but in this soft-seal execution the practical service limit is set by the washer or O-ring compound. Confirm the seal element for your fluid and temperature range with our engineers, and the fitting will not be the limiting part of the assembly.

Selection and Ordering

The 22211 BSP female flat seat fitting series covers the straight segment of BSP hydraulic hose fittings for flat seat connections, from -04 to -32, so most orders can be placed directly from the table above.

BSPP Thread Size Chart

Use this chart to identify the thread on your port. BSPP G threads are parallel; they are identified by measuring the thread outside diameter and counting the threads per inch.

Cross Reference Service {#by-oem-part-number}

Most maintenance teams buy against a legacy part number printed on the old drawing. Send us the OEM or distributor part number you currently use, with a photo of the fitting if possible. Our engineers identify the thread, the seat geometry, the hose size, and the body configuration, then confirm the exact 22211 equivalent before you place the order. The service covers flat seat fittings, BSP hydraulic hose fittings, and BSPP elbows in your inventory, and interchange confirmation is free. The cross reference sheet is returned in PDF for your records.

Packaging and Logistics

Assembly and Use Guide

Four-Step Crimping Procedure

1. Cut the hose square: use a hose cutter, never a hacksaw or an angle grinder. A square, clean end is the precondition for a uniform ferrule grip.
2. Mark the insert depth: read the insert depth for your hose series from the crimp data sheet and mark the line on the hose cover.
3. Lubricate and insert: apply a thin film of assembly lubricant to the stem and the hose bore, then push the fitting into the hose until the mark meets the ferrule.
4. Crimp and verify: select the die per the crimp table, crimp in one continuous stroke, then measure the crimp outside diameter with a caliper and compare with the tolerance.

Connecting the Flat Seat End

On the BSP female flat seat fitting, check that the seal element (bonded washer or O-ring) is in place and undamaged; replace it if cut, flattened, or hardened. Clean the flat seat faces with a lint-free cloth. Screw the swivel nut onto the male G-threaded stud by hand until the faces touch, then tighten to the torque listed for the thread size, wrenching the S2 nut hex. The flat faces compress the seal element, so no thread sealant is used. The nut swivels on the body, so position the hose routing first and tighten last; the hose will not be twisted by the connection.

Installation Warnings

• ❌ Never mix fittings and ferrules from different suppliers, even when the thread and hose sizes look identical. Stem geometry, ferrule hardness, and crimp parameters differ, and a mixed joint will leak or blow off under pressure.
• ❌ Never reuse a damaged or hardened seal element, and never fit a seal of the wrong compound. The washer or O-ring is the sealing element of this joint.
• ❌ Never confuse G (BSPP parallel) threads with R (BSPT taper) threads. A G thread with a flat seat seals by face contact and seal element; a taper thread seals by thread interference and needs sealant. The two are not interchangeable.
• ❌ Never crimp without the matching crimp data sheet. An under-crimped joint weeps, and an over-crimped joint damages the hose reinforcement.
• ❌ Never recrimp a fitting after a failed attempt, and never reuse a fitting removed from a hose.
• ✔ After assembly, pressure-test the circuit at 1.5x working pressure and inspect all joints for weepage.

OEM Customization and Quality Traceability

Customization Options

• Seal element supply: bonded washers or O-rings supplied with the fittings, in the compound matched to your fluid and temperature.
• Size and thread customization: non-standard G thread and hose combinations and special stem lengths machined to your drawing.
• Surface treatment customization: trivalent zinc (96 h), zinc-nickel (720 h), or Dacromet (1000 h) salt spray grades, selected by your environment and corrosion specification.
• Laser marking: your logo, part number, and batch code laser-marked on the hex for full field traceability.
• Material options: 304/316L stainless for chemical, marine, and food-contact circuits, with passivation certificates.

Quality and Traceability System

Every batch follows a documented flow: incoming steel with mill certificate → cold forging → CNC machining → heat treatment → plating → 100% thread gauge and dimension inspection → pressure test → laser marking → packing. The batch number on the carton links back to the raw material lot, the heat-treatment record, and the inspection report. Material test reports (MTR) are provided with every order on request, and third-party inspection reports (BV/SGS) can be arranged before shipment.

FAQ

Q: What is a BSP female flat seat fitting? A: It is a crimp-on fitting for braided hose whose port end is a swivel nut with a BSPP internal G thread (ISO 228-1); the fitting presents a flat sealing face that compresses a soft seal element (bonded washer or O-ring) against the flat seat of the mating male stud.

Q: How does a flat seat fitting seal? A: The parallel G thread pulls the two flat faces together, and the seal element between them is compressed to form the seal. The thread does not seal by interference; the washer or O-ring does the sealing.

Q: What is the difference between a flat seat fitting and a 60° cone fitting? A: The 60° cone version seals on machined cone faces, metal-to-metal or with an O-ring on the cone. The flat seat version seals on a flat face with a washer or O-ring between the faces. Flat seat seal elements are inexpensive and easy to replace in service, which keeps maintenance cost low.

Q: What seal element does the 22211 series use? A: The flat seat is designed for a bonded washer or O-ring, confirmed at order for your fluid and operating temperature. The seal element can be supplied with the fittings.

Q: Which hoses work with the 22211 series? A: The part numbers in the table are for braided hose from -04 to -32 (DN 6 to DN 50). For spiral hose, change the series number to 22212. Confirm your exact hose construction with our engineers, and the matching crimp data sheet will be supplied with the order.

Q: What is the difference between the 22211 and the 22241/22291 elbows? A: The 22211 is a straight termination: the hose approaches the port in line with the port axis. The 22241 (45°) and 22291 (90°) are elbows that turn the hose when the port axis and the hose run are not in line. All three use the same BSPP flat seat geometry.

Q: Can you provide crimp data for my hose? A: Yes. Every order includes the crimp data sheet for your hose construction, with insert depth, crimp outside diameter, and die selection. Send us your hose series and brand, and our engineers will confirm the crimp parameters before shipment.

Request a Quote

Tell us the BSPP thread, the hose dash size, the hose construction, the seal element preference, and the annual quantity. Whether you need stock BSP hydraulic hose fittings for distribution or a custom flat seat fitting for an OEM program, the quoting process is the same. For replacement orders, send the legacy part number and a photo, and our engineers will confirm the interchange before quoting. Every BSP female flat seat fitting leaves the HENGHUA factory pressure-tested, batch-coded, and backed by a written warranty. Request your quote, crimp data sheet, or drawing pack today, and we will respond within 24 hours.