Compact test points rated to 63 MPa. Pressure measurement, fluid sampling, and circuit ventilation — without breaking the line. By RUIHUA HARDWARE.
What Is a Hydraulic Test Coupling?
A test coupling is a small fitting installed directly on a hydraulic circuit. It lets you connect a pressure gauge or sample hose in seconds — no need to shut down or open the line. RUIHUA HARDWARE manufactures these in working pressures up to 63 MPa (630 bar), with a configurable part number system that covers most industrial requirements.
Common uses: commissioning checks, routine pressure verification, fluid sampling for contamination analysis, and system venting.
NBR (-20 to +100 °C), FKM (-20 to +200 °C), EPDM (-40 to +150 °C), Low-temp (-50 °C)
Surface Treatments
Zinc-plated, Zinc Nickel CrVI-free
Media
Hydraulic oils, mineral oil-based fluids (gas and other media — confirm with RUIHUA HARDWARE)
Why Choose RUIHUA HARDWARE Test Couplings?
630 Bar — Tested, Not Theoretical
630 bar is the tested working pressure, not a marketing figure. Mobile hydraulics, press machines, test rigs — these couplings hold under real conditions.
Four Seal Materials for Four Operating Windows
Hydraulic systems run different fluids at different temperatures. One seal does not fit all. RUIHUA HARDWARE offers four options:
NBR (N) — General hydraulic oil service, up to 100 °C. The cost-effective default.
FKM (F) — High-temperature environments up to 200 °C. Good chemical resistance.
EPDM (E) — Steam, brake fluid, polar fluids. Operates down to -40 °C.
Low-Temp (L) — Service down to -50 °C. Available on request.
Match the seal to your actual conditions. Don't default to the cheapest option — the wrong seal fails early and costs more in downtime.
Corrosion Resistance That Matches the Environment
Standard zinc plating works for indoor, dry conditions. For outdoor, marine, or washdown environments:
Zinc Nickel CrVI-free — Higher salt-spray resistance, EU REACH compliant. No regulatory issues for European customers.
Stainless Steel 304 — Solid general corrosion resistance at moderate cost.
Stainless Steel 316L — Molybdenum-added. Best for chloride and saltwater exposure.
Protection Caps That Do Not Walk Away
A loose cap means a contaminated port. RUIHUA HARDWARE offers four cap styles:
Cap Type
Code
Best For
Round Cap with Chain
R
General use — chain prevents loss
Hexagonal Cap with Chain
H
Wrench-tightenable, high-vibration zones
Universal Cap
E
Venting and protection combined
Plastic Cap
P
Cost-sensitive, indoor use
Chain-linked metal caps survive rough handling. That's why they're the industry standard.
Anti-Vibration O-Ring
Constant vibration loosens fittings over time. Add the anti-vibration O-ring (code 1 in the part number) and the problem goes away. Minimal cost, real field impact.
How to Read the Part Number
Every RUIHUA HARDWARE test coupling is built to spec using a six-segment code:
Surface – Seal – Cap – Series – O-ring – Marking
Z – N – R – TC – 0 – 0 │ │ │ │ │ └─ 0 = No mark / XX = Custom trademark │ │ │ │ └───── 0 = No O-ring / 1 = Anti-vibration O-ring │ │ │ └────────── TC = Test Coupling series │ │ └─────────────────── W = None / H = Hex / R = Round / E = Universal / P = Plastic │ └──────────────────────── N = NBR / F = FKM / E = EPDM / L = Low-temp └──────────────────────────── Z = Zinc / N = Zn-Ni / C = Color Zinc / e = Black / F = 304SS / L = 316LSS
Ordering Examples
Part Number
What It Means
Z-N-R-TC-0-0
Zinc-plated, NBR seal, Round chain cap, no O-ring, no custom mark
Confirm media compatibility with RUIHUA HARDWARE before ordering
Frequently Asked Questions
Can the RUIHUA HARDWARE test coupling handle gas service?
The standard design is rated for hydraulic oils and mineral-based fluids. For gas or non-standard media, contact RUIHUA HARDWARE before ordering. We verify seal and body material compatibility for your specific application.
What is the difference between 304 and 316L stainless steel test couplings?
304 stainless steel provides solid general corrosion resistance at a lower price. 316L adds molybdenum for superior resistance to chlorides and saltwater. Choose 316L for marine, coastal, or chemical processing environments. Both are available from RUIHUA HARDWARE.
Can RUIHUA HARDWARE engrave my company logo on the test coupling?
Yes. Use marking code XX in your part number and specify your trademark. RUIHUA HARDWARE laser-engraves custom logos on every unit.
Do I need the anti-vibration O-ring on my test coupling?
If your equipment runs with continuous vibration — pumps, compressors, mobile machinery — add it. The anti-vibration O-ring prevents loosening under vibration. It adds minimal cost but prevents a common failure mode in the field.
What thread sizes does the RUIHUA HARDWARE test coupling come in?
RUIHUA HARDWARE test couplings cover standard metric and BSP thread ranges. Contact us with your required thread size and we confirm availability immediately.
What is the minimum order quantity for RUIHUA HARDWARE test couplings?
MOQ is flexible for standard configurations. Contact the RUIHUA HARDWARE sales team with your quantity and specification. We respond within 24 hours with pricing and lead time.
Which seal material should I choose for my hydraulic test coupling?
NBR for general hydraulic oil up to 100 °C. FKM for high temperatures up to 200 °C and aggressive chemicals. EPDM for steam, brake fluid, and polar fluids down to -40 °C. Low-temp seal for service down to -50 °C. RUIHUA HARDWARE stocks all four options.
Does RUIHUA HARDWARE offer REACH-compliant surface treatments?
Yes. RUIHUA HARDWARE offers Zinc Nickel CrVI-free plating that meets EU REACH requirements. This is the standard choice for European customers who need regulatory compliance without sacrificing corrosion protection.
Get a Quote — RUIHUA HARDWARE
Need pricing, a size recommendation, or a delivery estimate? Reach out — we'll get back to you fast.
