HFP diaphragm seal · Wafer / pancake body · Flush process diaphragm
Flanged Pancake Diaphragm Seal
Compact wafer-style isolation for flanged off-line pressure measurement.
The HFP places a flush diaphragm in a thin pancake body at the process flange. Haygor publishes ANSI Raised Face, Ring Type Joint, and DIN EN 1092-1 choices, standard ANSI sizes from 2 to 4 inches, classes from 150 through 2500, and configurations with or without a backup flange.
- Compact wafer / pancake profile
- Available with or without backup flange
- ANSI Class 150 through 2500
Quick answer
What is a flanged pancake diaphragm seal?
A flanged pancake diaphragm seal is a thin, wafer-style pressure-isolation assembly installed at a flanged process connection. Its flush diaphragm is exposed to process pressure, while a sealed hydraulic fill fluid transfers that pressure to a gauge, transmitter, or switch without allowing process media into the instrument.
The Haygor HFP may be specified with or without a backup flange. This compact arrangement is useful where an integral full-body flange is unnecessary or installation profile matters, provided the mating flange, optional backup flange, bolting, gasket or ring, and complete joint stack-up are engineered as one assembly.
Hydraulic pressure transfer
How the HFP seal works
The HFP combines a compact flange-joint profile with a process-facing diaphragm and a sealed pressure-transfer system.
- 1
The wafer body locates at the process flange
The selected RF, RTJ, or DIN geometry is matched to the process connection and the intended backup-flange arrangement.
- 2
The flange joint clamps the assembly
Bolting and the optional backup flange support the pancake body while the gasket or ring forms the process seal.
- 3
Process pressure acts on the flush diaphragm
The process-facing diaphragm responds without the deeper chamber used by a recessed off-line seal.
- 4
Fill fluid transfers pressure to the instrument
A direct connection or remote capillary carries the hydraulic pressure signal to the gauge, transmitter, or switch.
Application fit
When a flanged pancake seal is a strong choice
The HFP is designed for off-line flanged pressure points where a flush diaphragm and compact wafer-style installation are preferred.
Installation advantages
- Thin pancake body minimizes the installed profile
- Flush diaphragm reduces the recessed process cavity
- Available with or without a backup flange
- ANSI Raised Face, ANSI RTJ, and DIN choices
- Optional calibration or flushing ring
Selection conditions that favor the HFP
- The flange joint can properly support and clamp a wafer-style seal
- Flange standard, size, class, face, and bolt requirements are known
- A flush diaphragm is preferred for the process media
- The selected diaphragm and ring materials are chemically compatible
- The complete assembly pressure and temperature limits are verified
Common industrial settings
Compact isolation for demanding flanged measurement points
- Chemical processing
- Refining
- Petrochemical
- Oil & gas
- Power & utilities
- Water & wastewater
Catalog specifications
HFP flange, backup-flange, connection, and dimension choices
The values below summarize the HFP selections published in Haygor's diaphragm seal ordering guide.
Compact body format
Flush-diaphragm seal installed as part of the flange joint.
Three published face families
ANSI Raised Face, ANSI Ring Type Joint, and DIN Raised Face.
Published ANSI sizes
2-, 3-, and 4-inch process selections.
Published ANSI classes
Class availability is dependent on size and face style.
| Selection | Published choices | Catalog note |
|---|---|---|
| Flange type | ANSI Raised Face; ANSI Ring Type Joint; DIN Raised Face EN 1092-1 | Match the mating face, gasket or ring, bolting, and applicable piping standard. |
| ANSI process size | 2, 3, and 4 in. | Additional sizes may be available by request. |
| DIN process size | DN50, DN80, DN100, and DN125 | Availability depends on the selected PN rating. |
| ANSI pressure class | 150, 300, 600, 900, 1500, and 2500 | Not every class is published for every size and face style. |
| DIN PN rating | PN10/40 for DN50; PN10/16 and PN25/40 for DN80-DN125; PN63, PN100, PN160, and PN250 for DN50-DN125 | Confirm current combinations and dimensions with Haygor. |
| Instrument connection | Weld or 1/4 NPT | The weld connection is not listed with Titanium or Zirconium body construction. |
| Body material | 316/316L stainless steel; Titanium; Zirconium 702 | Titanium or Zirconium body construction is required with the matching diaphragm material. |
| Backup flange | Not required; 316/316L stainless steel; carbon steel | Verify the complete flange stack-up, support, bolt length, and pressure-temperature rating. |
Published HFP ANSI Raised Face dimensions
Dimensions are in inches. T is the flange thickness, flange diameter is the backup-flange outside diameter, and A and B correspond to Haygor's dimensional drawing. RTJ dimensions and groove numbers are published separately in the ordering guide.
| Diaphragm | Flange | Bolt pattern | T | Flange diameter | A | B |
|---|---|---|---|---|---|---|
| 2.4 in. | 2 in. Class 150 | (4), 0.75 in. holes, 4.75 in. B.C. | 0.75 | 6.00 | 1.08 | 3.62 |
| 2.4 in. | 2 in. Class 300 | (8), 0.75 in. holes, 5.00 in. B.C. | 0.88 | 6.50 | 1.08 | 3.62 |
| 2.4 in. | 2 in. Class 600 | (8), 0.75 in. holes, 5.00 in. B.C. | 1.25 | 6.50 | 1.08 | 3.62 |
| 2.4 in. | 2 in. Class 900 | (8), 1.00 in. holes, 6.50 in. B.C. | 1.75 | 8.50 | 1.08 | 3.62 |
| 2.4 in. | 2 in. Class 1500 | (8), 1.00 in. holes, 6.50 in. B.C. | 1.75 | 8.50 | 1.08 | 3.62 |
| 2.4 in. | 2 in. Class 2500 | (8), 1.12 in. holes, 6.75 in. B.C. | 2.25 | 9.25 | 1.08 | 3.62 |
| 3.5 in. | 3 in. Class 150 | (4), 0.75 in. holes, 6.00 in. B.C. | 0.94 | 7.50 | 1.08 | 5.00 |
| 3.5 in. | 3 in. Class 300 | (8), 0.88 in. holes, 6.62 in. B.C. | 1.12 | 8.25 | 1.08 | 5.00 |
| 3.5 in. | 3 in. Class 600 | (8), 0.88 in. holes, 6.62 in. B.C. | 1.50 | 8.25 | 1.08 | 5.00 |
| 3.5 in. | 3 in. Class 900 | (8), 1.00 in. holes, 7.50 in. B.C. | 1.75 | 9.50 | 1.08 | 5.00 |
| 3.5 in. | 3 in. Class 1500 | (8), 1.25 in. holes, 8.00 in. B.C. | 2.13 | 10.50 | 1.08 | 5.00 |
| 3.5 in. | 3 in. Class 2500 | (8), 1.38 in. holes, 9.00 in. B.C. | 2.87 | 12.00 | 1.08 | 5.00 |
| 3.5 in. | 4 in. Class 150 | (8), 0.75 in. holes, 7.50 in. B.C. | 0.94 | 9.00 | 1.08 | 6.00 |
| 3.5 in. | 4 in. Class 300 | (8), 0.88 in. holes, 7.88 in. B.C. | 1.25 | 10.00 | 1.08 | 6.00 |
| 3.5 in. | 4 in. Class 600 | (8), 1.00 in. holes, 8.50 in. B.C. | 1.75 | 10.75 | 1.08 | 6.00 |
| 3.5 in. | 4 in. Class 900 | (8), 1.25 in. holes, 9.25 in. B.C. | 2.00 | 11.50 | 1.08 | 6.00 |
Confirm current dimensions, flange-standard availability, backup-flange requirements, pressure and temperature limits, diaphragm displacement, material compatibility, gasket or ring selection, bolting, fill fluid, and the rating of the complete seal-and-instrument assembly with Haygor before order entry.
Configure the complete assembly
HFP materials, backup flange, flushing rings, ports, and options
Build the flange joint and remote-seal system as one engineered assembly rather than selecting the pancake body in isolation.
Joint geometry
Specify ANSI or DIN, nominal size, class or PN rating, Raised Face or RTJ geometry, gasket or ring, and mating-flange details.
Backup flange and bolting
Choose no backup flange or a supplied flange, then verify support, bolt quantity, hole pattern, bolt length, preload, and installation access.
Diaphragm and wetted parts
Select process-facing materials compatible with the actual media, concentration, pressure, temperature, and cleaning method.
System and service details
Define the instrument connection, direct or remote mounting, fill fluid, capillary, ambient conditions, flushing access, and documentation.
Published diaphragm materials
Match the process-facing diaphragm to the media
- 316 / 316L stainless steel
- 304 / 304L stainless steel
- Tantalum
- Alloy 20
- Alloy C-276
- Alloy B-3
- Monel 400
- Alloy 600
- Alloy 2205
- Nickel 200 / 201
- Titanium
- Zirconium 702
Material availability can depend on body construction, flange type, ring selection, and fabrication method. Confirm every wetted component in the final configuration.
Published option codes
Surface treatments, plugs, and documentation
- /AU
- Gold-plated diaphragm
- /NS
- PTFE-coated diaphragm for non-stick service only
- /P1
- Single pipe plug for flush port
- /P2
- Dual pipe plugs for flush ports
- /MC
- Material certification with MTRs
Selection note
Use system-level limits, not a single component value
The usable HFP range depends on flange standard and rating, backup-flange and bolting arrangement, diaphragm and body materials, process pressure and temperature, fill fluid, instrument, capillary length and routing, ambient conditions, mounting orientation, and required measurement performance.
Compare flange and diaphragm geometry
Related Haygor diaphragm seals
Compare integral-flange, recessed, threaded, and flushing-access designs when the process joint or maintenance strategy calls for a different interface.
Frequently asked questions
Flanged pancake diaphragm seal FAQ
These answers summarize Haygor's published HFP product data. Final selection should be based on the complete process, flange joint, instrument, and installation requirements.
Ask Haygor a technical questionWhat is a flanged pancake diaphragm seal?
A flanged pancake diaphragm seal is a compact wafer-style pressure-isolation assembly installed at a flanged process connection. Its flush diaphragm separates the process media from the pressure instrument, while a sealed fill fluid transfers pressure to a gauge, transmitter, or switch.
How is the HFP different from the HFF flush flanged seal?
The HFP uses a thin pancake or wafer body and may be supplied with or without a backup flange. The HFF is a flush flanged seal with an integral rotating flange. The preferred design depends on the flange joint, available space, bolting arrangement, maintenance approach, and process requirements.
Can the HFP be supplied without a backup flange?
Yes. Haygor lists a no-backup-flange selection and states that the HFP is sold with or without the flange. The mating flange, support, bolt length, gasket or ring, and complete joint stack-up still must be verified for the installation.
Which flange standards and sizes are published for the HFP?
Haygor lists ANSI Raised Face, ANSI Ring Type Joint, and DIN Raised Face to EN 1092-1. Published ANSI sizes are 2, 3, and 4 inches. Published DIN sizes are DN50, DN80, DN100, and DN125.
What pressure classes and PN ratings are listed?
The ordering guide lists ANSI Classes 150, 300, 600, 900, 1500, and 2500, plus DIN PN combinations through PN250. Availability is dependent on nominal size, face style, material, and the complete assembled system.
What instrument connections are available?
The HFP ordering guide lists a weld connection and a 1/4-inch NPT connection. The weld connection is not listed with Titanium or Zirconium body construction.
Can the HFP include a calibration or flushing ring?
Yes. Published selections include no ring or a ring in several metals or PTFE. Flushing connections can be omitted or specified as single or dual 1/4-inch or 1/2-inch NPT female ports, or single or dual 1/4-inch or 1/2-inch pipe socket-weld connections.
What information should I provide for an HFP quote?
Provide the process media and concentration, operating and maximum pressure, process and ambient temperature, flange standard, nominal size, class or PN rating, face style, backup-flange requirement, mating-flange details, instrument model and connection, wetted-material requirements, flushing-ring details, fill-fluid requirements, mounting method, and documentation needs.
Move from flange-joint data to an HFP configuration
Configure a flanged pancake seal or send the complete application to Haygor.
Use the configurator for a guided starting point, or request a quote for flange, backup-flange, diaphragm, material, flushing-ring, fill-fluid, and instrument review.