HCT diaphragm seal · Flow-wedge interface · 300 PSI MWP
Chemical Tee / Wedge Diaphragm Seal
Purpose-built pressure isolation for chemical tee and flow-wedge measurement points.
The Haygor HCT uses a broad, flush diaphragm and dedicated eight-hole flange pattern to fit compatible chemical tee or wedge assemblies. Haygor publishes a 300 PSI maximum working pressure and requires the body material to match the diaphragm material.
- Chemical tee / flow-wedge mounting geometry
- 300 PSI published maximum working pressure
- Matched body and diaphragm material
Quick answer
What is a Chemical Tee / Wedge diaphragm seal?
A Chemical Tee / Wedge diaphragm seal is a specialized pressure-isolation assembly shaped to mate with a compatible chemical tee or flow-wedge connection. Process pressure acts on the broad corrugated diaphragm, while a sealed hydraulic fill transfers that pressure to a gauge, transmitter, switch, or controller without exposing the instrument to the process media.
The HCT is not a general-purpose ANSI flange. Its fixed catalog geometry, broad diaphragm, and matched body-and-diaphragm alloy are intended for the corresponding wedge interface. The mating tee or wedge, gasket, bolting, instrument, fill system, and operating conditions must be reviewed as one pressure-measurement assembly.
Hydraulic pressure transfer
How the HCT seal works
The HCT combines a dedicated wedge-mounting interface with diaphragm isolation and a filled pressure-transfer path.
- 1
The flange mates to the wedge assembly
The eight-hole HCT pattern aligns with a compatible chemical tee or flow-wedge connection.
- 2
The joint secures the process interface
Bolting and the selected gasket or sealing arrangement complete the connection to the mating hardware.
- 3
Process pressure acts on the diaphragm
The broad corrugated diaphragm responds while separating process media from the instrument and fill passage.
- 4
Fill fluid carries pressure to the instrument
A direct-mounted or remote instrument receives the hydraulic pressure signal without direct process contact.
Application fit
Specialized pressure isolation for flow-wedge connections
Haygor publishes the HCT specifically for chemical tee or wedge flanged flow-wedge applications. The broad diaphragm and extensive alloy choices support tailored pressure-measurement assemblies where the mating geometry is already defined.
Where the HCT can fit
- Compatible chemical tee pressure connections
- Flow-wedge primary-element pressure taps
- Direct or remote gauge and transmitter assemblies
- Applications requiring a broad flush sensing diaphragm
- Process chemistry requiring a selected corrosion-resistant alloy
Selection conditions to verify
- Exact wedge or chemical tee manufacturer and mating drawing
- Operating pressure, process temperature, and transient conditions
- Process media, concentration, phase, solids, and cleaning method
- Matched body and diaphragm alloy plus gasket and hardware
- Instrument range, fill fluid, capillary, mounting, and ambient exposure
Common process settings
Measurement points where the wedge interface is part of the design
- Chemical processing
- Petrochemical
- Refining
- Flow measurement
- Specialty process skids
- Corrosive service
Published configuration envelope
HCT connections, pressure limit, geometry, and material rule
These selections summarize Haygor's published HCT ordering information. Confirm current availability and the completed filled-system limits before release.
Weld connection
Instrument weld connection; not published with Titanium or Zirconium.
1/4-inch NPT
Threaded instrument connection for compatible direct or attachment arrangements.
1/2-inch NPT
Larger threaded instrument connection selection.
PSI maximum
Published maximum working pressure for the HCT.
Mounting holes
0.33-inch holes on a 4.38-inch bolt circle.
Matched material
Haygor states the body material always matches the diaphragm material.
The published 300 PSI value is a maximum working pressure, not a substitute for application review. Temperature, process chemistry, gasket and mounting hardware, mating wedge assembly, instrument, fill fluid, capillary, ambient conditions, and required accuracy can further limit the completed system.
Dimensions and ordering selection
Match the HCT to the wedge, alloy, and instrument system
The HCT has a specialized published geometry. Use the drawing and ordering choices as a catalog reference, then verify the exact mating assembly before manufacturing or installation.
Published dimensional callouts
Fixed catalog geometry
- Overall outside diameter
- 5.00 in.
- Published lower diameter
- 3.78 in.
- Mounting holes
- 8 holes
- Hole diameter
- 0.33 in.
- Bolt circle
- 4.38 in.
- Vertical callouts
- 0.66 in.; 0.50 in.; 0.50 in. as shown
| Code | Body material | Code | Body material |
|---|---|---|---|
| S6 | 316 / 316L stainless steel | S4 | 304 / 304L stainless steel |
| C2 | Alloy 20 | HC | Alloy C-276 |
| H2 | Alloy B-2 | M4 | Monel 400 |
| DP | Alloy 2205 | SD | Alloy 2507 |
| NI | Nickel 201 / 200 | TI | Titanium |
| Z7 | Zirconium 702 | — | Confirm current matched material code |
| Code | Diaphragm material | Code | Diaphragm material |
|---|---|---|---|
| S6 | 316 / 316L stainless steel | S4 | 304 / 304L stainless steel |
| C2 | Alloy 20 | HC | Alloy C-276 |
| HB | Alloy B-3 | M4 | Monel 400 |
| I6 | Alloy 600 | DP | Alloy 2205 |
| NI | Nickel 201 / 200 | TI | Titanium |
| Z7 | Zirconium 702 | — | Confirm current matched material code |
Haygor's HCT feature statement says the body material always matches the diaphragm material. The legacy ordering table contains some different alloy names or codes between the two columns, including Alloy B-2 versus B-3 and body-only or diaphragm-only entries. Confirm the current compatible matched material selection with Haygor rather than pairing unmatched catalog rows.
Published option codes
Surface and documentation options
- /AU
- Gold-plated diaphragm
- /NS
- PTFE-coated diaphragm for non-stick service only
- /MC
- Material certification with MTRs
Information to confirm before release
- Chemical tee or wedge manufacturer and current mating drawing
- Operating, maximum, and transient pressure within the 300 PSI published maximum
- Process and ambient temperature plus media composition
- Matching body and diaphragm material selection
- Instrument connection, model, range, and mounting method
- Direct mount or capillary length, armor, fill fluid, and orientation
- Gasket, bolt material, bolt length, torque, and support
- Gold plating, non-stick coating, and material-document requirements
Compare process interfaces
Related Haygor diaphragm seals
Use the HCT when the mating chemical tee or wedge geometry is required. Compare conventional flanged, wafer, saddle, or threaded designs for other process connections.
Frequently asked questions
Chemical Tee / Wedge seal FAQ
These answers summarize Haygor's published HCT ordering information and dimensional drawing. Final selection requires review of the exact wedge assembly, process, filled system, and installation.
Ask Haygor a technical questionWhat is a Chemical Tee / Wedge diaphragm seal?
The Haygor HCT is a specialized diaphragm seal designed to fit compatible chemical tee or flow-wedge applications. A broad process-facing diaphragm isolates the pressure instrument from the process media while a sealed fill fluid transfers pressure to the attached instrument.
Is the HCT a standard ANSI process flange?
No. Haygor publishes the HCT as a Chemical Tee / Wedge flanged seal for flow-wedge applications. Its catalog drawing shows a dedicated 5.00-inch outside diameter and an eight-hole mounting pattern. Confirm the exact mating tee or wedge drawing, joint hardware, gasket, and installation dimensions before ordering.
What is the maximum working pressure of the HCT?
Haygor publishes a 300 PSI maximum working pressure for the HCT. The allowable completed-system pressure may also depend on process temperature, material, instrument, fill fluid, mounting arrangement, and the mating chemical tee or wedge assembly.
What mounting dimensions are published?
The published drawing shows a 5.00-inch outside diameter, a 3.78-inch diameter dimension, and eight 0.33-inch-diameter holes on a 4.38-inch bolt circle. It also shows 0.66-inch and two 0.50-inch vertical dimensions. Use the current Haygor drawing for fabrication and replacement verification.
Which instrument connections are available?
Haygor lists a weld instrument connection, 1/4-inch NPT, and 1/2-inch NPT. The weld connection is not listed with Titanium or Zirconium construction.
Which body and diaphragm materials are published?
Published HCT material families include stainless steels, Alloy 20, Alloy C-276, nickel alloys, Monel 400, duplex stainless steel, Titanium, and Zirconium 702. Haygor states that the body material always matches the diaphragm material. Confirm the exact current matched alloy code because the legacy catalog lists some different alloy designations between the body and diaphragm columns.
What does the PTFE-coated diaphragm option provide?
Haygor identifies the /NS PTFE-coated diaphragm option as non-stick only and specifically states that it is not for corrosion protection. Select a corrosion-compatible base diaphragm and body alloy for the actual process chemistry.
Can the HCT be direct mounted or used with a capillary?
The HCT can be incorporated into a pressure measurement assembly with a compatible instrument connection. Direct mounting, remote capillary, instrument range, fill fluid, ambient temperature, and response requirements should be reviewed as one filled system with Haygor.
What information should I provide for an HCT quote?
Provide the chemical tee or wedge manufacturer and drawing, mating dimensions, process media and concentration, operating and maximum pressure, process and ambient temperature, instrument model and range, direct or remote mounting, required body and diaphragm alloy, gasket and bolting details, fill-fluid constraints, and documentation requirements.
Move from wedge geometry to an HCT configuration
Configure a Chemical Tee / Wedge seal or send the complete flow-wedge application to Haygor.
Use the configurator for a guided starting point, or request a quote with the mating drawing, pressure, temperature, process media, matched alloy, instrument, fill system, gasket, bolting, and documentation requirements.