Unlike standard pipe unions, this component integrates a borosilicate glass disc into the center bore, creating a 360-degree viewing area while maintaining the structural integrity of a threaded pressure fitting. The union body splits into two machined halves joined by a hex collar, enabling installation or removal without rotating connected hoses or rigid tubing. All dimensions, thread forms, and seal gland geometries are manufactured to client drawings with no reliance on casting processes.
CNC Manufacturing Process
Every unit originates from certified stainless steel round bar:
- Bar stock facing & center drilling: Automatic lathes prepare blanks with precise length control.
- CNC turning: External hex profiles, internal bores, and thread pre-forms machined in single setups.
- Glass seat micro-boring: Precision boring heads cut the counterbore and gland groove to ±0.02 mm.
- Thread rolling or cutting: NPT, BSPP, BSPT, or UNF threads generated per specification.
- Surface finishing: Passivation or electropolishing applied to restore corrosion resistance.
- Assembly & seal testing: Borosilicate disc installed with PTFE or FKM gasket; hydrostatic test to 1.5× working pressure.
- Final inspection: Go/no-go thread gauges and bore micrometers verify conformity.
Material Specifications
|
Element |
Specification |
Notes |
|
Body Material |
304 or 316L Stainless Steel |
316L standard for glycol and DI water loops |
|
Sight Glass |
Borosilicate, tempered |
Thermal shock resistant to 150°C |
|
Seals |
FKM (standard), EPDM, FFKM |
Selected per coolant chemistry |
|
Retainer |
316L Split Ring or Threaded Collar |
Field-replaceable glass design available |
Technical Parameters
|
Thread Range: |
1/8" NPT through 2" BSPP; metric threads M10×1 to M42×2 |
|
Pressure Rating: |
10 bar standard; 35 bar reinforced configuration with sapphire glass |
|
Temperature Range: |
-20°C to +150°C (borosilicate); +200°C with sapphire upgrade |
|
Surface Finish: |
Ra 0.8 μm standard; Ra 0.4 μm electropolished for high-purity loops |
|
Hex Sizes: |
Standard SAE or DIN hex profiles; custom wrench flats available |
Quality Assurance
- Dimensional Verification: CMM inspection on first article; SPC tracking on bore diameters
- Pressure Testing: 100% hydrostatic test at 1.5× rated pressure; helium leak test optional
- Thread Inspection: Pitch diameter checked with calibrated thread gauges per ASME B1.20.1
- Glass Integrity: Edge chip inspection and polarized light strain analysis before assembly
- Certifications: ISO 9001; material RoHS and REACH compliance documentation included
Application Sectors
|
Data Center Liquid Cooling: |
Manifold and CDU (Coolant Distribution Unit) visibility ports |
|
Laser & Optics Equipment: |
Chiller loop inspection points for resonator cooling circuits |
|
Medical Imaging: |
MRI and CT scanner closed-loop glycol monitoring |
|
Battery Energy Storage (BESS): |
Thermal runaway prevention through coolant flow verification |
|
Semiconductor Manufacturing: |
High-purity cooling lines requiring particle-free electropolished surfaces |
FAQ
|
Q1: |
What thread types are available for a stainless union sight glass liquid cooling component? |
|
A1: |
We machine NPT, BSPP, BSPT, UNF, and metric parallel/taper threads as standard. AN flare and VCR face-seal configurations are also available for semiconductor and aerospace cooling systems. |
|
Q2: |
Can the borosilicate glass in a liquid cooling sight glass be replaced in the field? |
|
A2: |
Yes. Our split-retainer and threaded-collar designs allow glass replacement using standard tools without discarding the stainless body. Replacement glass kits with pre-cut gaskets can be supplied separately. |
|
Q3: |
What is the maximum working temperature of a stainless steel union sight glass? |
|
A3: |
Borosilicate glass configurations are rated to 150°C continuous. For higher temperatures up to 200°C, we recommend sapphire glass with an Inconel 718 retaining ring and upgraded FFKM seals. |
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