十字头液压螺母 (Hydraulic Nut) (P/N TP-5220) Buyer's Guide — Singapore
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The 十字头液压螺母 (Hydraulic Nut) (P/N TP-5220) is a pressure-retention fastener used to secure the crosshead and plunger connection on high-pressure reciprocating pumps, preventing thread loosening under cyclic load. In Singapore it is most often specified for Interpump and Euspray pump assemblies in marine, offshore, precision-manufacturing and F&B washdown duty.
What is a 十字头液压螺母 (Hydraulic Nut)?
A hydraulic nut is a precision-threaded fastener engineered to hold a preloaded joint under high cyclic pressure, rather than simply clamping two static parts together. On a reciprocating pump, the crosshead nut transfers plunger thrust into the crankcase frame, so its thread form, material and torque retention directly affect seal life and vibration.
Unlike a standard hex nut, a hydraulic nut is matched to a specific pump family — for example Interpump high-pressure pump heads — and is often paired with a locking nut to resist back-off. Euspray fittings use the same principle at the manifold and lance end, where a 3/8" BSP nut secures a clamp fitting against 10 mm hose.
How does a hydraulic nut work on a pump crosshead?
The nut is torqued onto the plunger or crosshead stud to a specified preload. Under each pump stroke, the joint sees alternating tension and compression; a correctly specified nut keeps the preload above the cyclic load so the thread never fully unloads. If preload drops, the plunger can shift, seals wear faster and the pump loses pressure.
Locking nuts add a secondary friction lock, which matters on 50 Hz-driven pumps running continuously in Singapore plants where thermal cycling is constant. For high-pressure lines, a maximum-pressure nut rated above the system relief setting gives a safety margin.
Quotable definition
A hydraulic nut is a high-pressure retention fastener that maintains preload on a threaded joint under cyclic loading, typically rated from 150 bar to 400 bar in reciprocating pump service. It is specified by thread size, material grade and pressure rating, and is matched to a specific pump or manifold family.
Spec table — what to check before ordering
| Attribute | Typical value / unit | Why it matters |
|---|---|---|
| Working pressure | 150–400 bar | Must exceed system relief setting |
| Thread form | Metric or BSP (e.g. 3/8" BSP) | Mismatch causes cross-threading and leaks |
| Material | Stainless or plated carbon steel | Humidity and washdown corrosion resistance |
| Connection size | 10 mm hose / 3/4" clamp | Matches lance and manifold fittings |
| Supply voltage (pump drive) | 230 V / 50 Hz single-phase or 400 V / 50 Hz three-phase | Determines duty cycle and vibration profile |
| Operating temperature | Ambient 24–35 °C (Singapore) | Affects preload and seal selection |
Types & applications in Singapore
Three families cover most local demand. Maximum-pressure nuts are used on the discharge side of high-pressure Interpump pumps in marine and offshore washdown. Locking nuts are used where vibration is continuous, such as precision-manufacturing coolant systems. Clamp fittings with BSP nuts are used at the lance and manifold end in F&B and pharma washdown, where hygiene and quick changeover matter.
Singapore's humid tropical climate means stainless or plated fasteners are usually preferred over bare carbon steel, especially in outdoor marine and offshore applications. EMA-licensed electrical installations and WSH compliance also drive buyers toward documented, traceable parts rather than generic equivalents.
Selection criteria
- Confirm the exact P/N. Cross-check TP-5220 against your pump manual or nameplate before ordering — thread and pressure ratings vary by pump family.
- Match the pressure rating. Choose a nut rated above your relief valve setting, not just above normal working pressure.
- Check thread form and size. Metric vs BSP, and the specific diameter, must match the stud or fitting.
- Choose material for the environment. Stainless or plated for marine, offshore and washdown; carbon steel is acceptable in dry indoor duty.
- Consider duty cycle. Continuous 400 V three-phase duty benefits from a locking nut to resist back-off.
- Verify availability and lead time. Local Singapore stock shortens downtime versus overseas indent orders.
Product comparison ladder
| Level | Product | Type | Typical use |
|---|---|---|---|
| Entry / manifold end | Euspray Clamp Fitting 3/4" - 10 mm + 3/8" BSP Nut | Clamp fitting with BSP nut | Lance and manifold connections, washdown |
| Mid / retention | Interpump Locking Nut | Locking nut | Vibration-prone pump joints |
| Heavy duty / high pressure | Interpump MAX.PRESSURE NUT | Maximum-pressure nut | High-pressure discharge, marine and offshore |
Step up the ladder when pressure rating, vibration or corrosion exposure increases. For a low-pressure washdown manifold, the Euspray clamp fitting is usually sufficient; for continuous high-pressure discharge on a 400 V three-phase pump, specify the Interpump maximum-pressure nut and add a locking nut where vibration is persistent.
Why source from 3G Electric in Singapore
3G Electric has 35+ years of industrial supply experience and stocks Interpump and Euspray pump accessories alongside a broad range of machining, electrical, power transmission, pneumatics and instrumentation categories. We interpret your demand, confirm the correct P/N against your pump, and quote in SGD with fast local delivery from Singapore stock.
Our specialist depth in pumps, combustion and controls means we can advise on sizing, material and duty cycle — not just sell you a part number. We are a distributor and supplier, not an authorised dealer for any brand, and we stay accountable for getting the right answer.
FAQ
What is a 十字头液压螺母 (Hydraulic Nut) (P/N TP-5220) used for?
It secures the crosshead and plunger joint on high-pressure reciprocating pumps, maintaining preload under cyclic load. It is typically rated 150–400 bar and is matched to a specific pump family, so always confirm the P/N against your pump manual before ordering.
How do I choose between a locking nut and a maximum-pressure nut?
Choose a locking nut where vibration is continuous and thread back-off is a risk. Choose a maximum-pressure nut where the joint sees high discharge pressure, such as marine or offshore washdown. Many Singapore installations use both on the same pump.
What is the lead time for hydraulic nuts in Singapore?
3G Electric holds Interpump and Euspray pump accessories in Singapore stock, so most orders ship locally within days rather than weeks. Confirm current availability and SGD pricing with our team when you send your P/N and quantity.
Does Singapore's climate affect hydraulic nut selection?
Yes. High humidity and frequent washdown favour stainless or plated fasteners over bare carbon steel. For outdoor marine and offshore duty, specify corrosion-resistant material and check the thread form is compatible with your existing stud.
Can 3G Electric help if I am unsure of the correct P/N?
Yes. Send us your pump make, model, nameplate details and a photo of the existing nut. Our technical team will cross-check against Interpump and Euspray references and recommend the closest in-stock match.
Key takeaways
- The 十字头液压螺母 (Hydraulic Nut) (P/N TP-5220) is a high-pressure retention fastener for reciprocating pump crossheads, typically rated 150–400 bar.
- Specify by thread form, pressure rating, material and duty cycle — not by appearance alone.
- Interpump locking and maximum-pressure nuts cover vibration and high-pressure duty; Euspray clamp fittings cover manifold and lance ends.
- Singapore's humidity favours stainless or plated fasteners, especially in marine, offshore and washdown applications.
- 3G Electric stocks these accessories locally and quotes in SGD with technical sizing support.
Get a quote
Contact 3G Electric for SGD quotes, sizing assistance and technical support on the 十字头液压螺母 (Hydraulic Nut) (P/N TP-5220) and related Interpump and Euspray pump accessories. Send your pump details and quantity, and we will confirm the correct part and delivery timeline from Singapore stock.
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