Can the Hydraulic three-way valve "L" with NPT female thread, type SK3L operate safely at -40Â°C given its POM ball and NBR stem seals?

Hydraulic three-way valve "L" with NPT female thread, type SK3L cannot be considered fully safe for continuous operation at â40Â°C given the stated seal materials. Although the valveâs POM ball has an operating range down to â40Â°C, the NBR stem seals are rated only from â20Â°C to +100Â°C. At â40Â°C NBR becomes much harder and less elastic, losing sealing ability and becoming prone to cracking or leakage under pressure and dynamic movement. This raises risks of external leaks, internal bypass, reduced actuation force, and premature seal failure.especially in high-pressure hydraulic installations. If the valve must be used at â40Â°C, options are: replace the stem seals with a low-temperature-compatible material (e.g., FKM variants rated for â40Â°C or better, or specific low-temp NBR compounds), select a valve version specified for â40Â°C operation, or run validation testing under expected pressure/cycling conditions. Without such changes or testing, do not assume safe operation at â40Â°C.

Does the Hydraulic three-way valve "L" with NPT female thread, type SK3L require special maintenance when used near +100Â°C due to POM and NBR seals?

Hydraulic three-way valve "L" with NPT female thread, type SK3L does not require special maintenance solely because it is used near +100Â°C, provided operating temperature does not exceed the specified limits for its seals (POM: -40Â°C to +100Â°C; NBR: -20Â°C to +100Â°C). However, at the upper limit you should monitor for accelerated seal wear or hardening: inspect seals more frequently, check for leaks, and consider shortening routine maintenance intervals. If continuous operation at or above +100Â°C is expected, evaluate alternative seal materials rated for higher temperatures or consult the manufacturer. Ensure system fluid and pressure remain within valve specifications to avoid additional stress on POM and NBR components.

Are there compatibility concerns for hydraulic fluids with the Hydraulic three-way valve "L" with NPT female thread, type SK3L?

Hydraulic three-way valve "L" with NPT female thread, type SK3L. compatibility considerations: 1. Seal materials determine primary compatibility: - Ball seal: POM (polyoxymethylene). Compatible with most mineral oils, many synthetic esters and some PAOs at typical hydraulic temperatures. POM is moderately resistant to oils but can be affected by strong polar solvents, certain brake fluids (glycols), and aggressive chemicals. - Stem seal: NBR (nitrile rubber). NBR is widely used for mineral oils and many petroleum-based hydraulic fluids, but has limited resistance to phosphate esters, some synthetic fluids, and aggressive hydraulic fluids containing high concentrations of esters, ketones, or aromatics. NBR performs well between about -20Â°C and +100Â°C (as noted). 2. Temperature limits affect fluid choice: - Operating temperature ranges given (POM: -40Â°C to +100Â°C; NBR: -20Â°C to +100Â°C) mean fluids that extend outside these ranges (very low pour points or high-temperature degradation) may harden, swell, or lose sealing integrity. Ensure fluid viscosity at lowest operating temperature remains within valve/system design. 3. Fluids to avoid or verify: - Phosphate ester fluids (e.g., Skydrol) can cause NBR swelling/degradation. not recommended unless manufacturer confirms compatibility. - Strongly polar fluids, some biodegradable esters or synthetic fluids may attack POM or NBR. verify with fluid supplier. - Water-glycol fluids and DOT-type brake fluids (glycol ethers) can be incompatible with POM and NBR. 4. Fluids generally acceptable: - Standard mineral-based hydraulic oils (H, HV, HM types) and many petroleum-based synthetic fluids compatible with NBR/POM at normal temperatures. 5. Recommendations: - Confirm the exact hydraulic fluid family and operating temperature range before use. - If using non-mineral, biodegradable, fire-resistant, or phosphate-ester fluids, consult valve manufacturer or perform compatibility testing. - For extended high-temperature or low-temperature operation, verify material performance (swelling, hardness, sealing) with fluid supplier. - Consider alternative seal materials (e.g., FKM, EPDM, PTFE) if required for specific fluids. consult manufacturer. Summary: Hydraulic three-way valve "L" with NPT female thread, type SK3L is broadly compatible with standard mineral hydraulic oils, but compatibility with phosphate esters, certain synthetics, biodegradable fluids, water-glycols and aggressive solvents is uncertain due to POM and NBR seals. Always verify fluid family and temperature range with the manufacturer or supplier before use.

Hydraulic three-way valve “L” with NPT female thread, type SK3L

All products, Directional control valves/

Three-way ball valve “L” type SK3L with internal NPT thread, designed for high-pressure hydraulic installations. Material: steel (body, ball, stem). Seals: POM (ball), NBR (stem). Operating temperature: from -40°C to +100°C (POM); from -20°C to +100°C (NBR).

List of product variants

Article number	Product variant name	Nominal inner diameter	Working pressure [bar]
HZ-SK3L-N-20	Three-way valve "L" DN32 with 1.1/4" NPT thread, POM/NBR	32	350
HZ-SK3L-N-24	Three-way valve "L" DN40 with 1.1/2" NPT thread, POM/NBR	40	350
HZ-SK3L-N-32	Three-way valve "L" DN50 with 2" NPT female thread, POM/NBR	50	350

Three-way ball valve “L” type SK3L with internal NPT thread, designed for high-pressure hydraulic installations. Material: steel (body, ball, stem). Seals: POM (ball), NBR (stem). Operating temperature: from -40°C to +100°C (POM); from -20°C to +100°C (NBR).

Additional information

Material	CS – steel (cast iron)

Additional information

Material	CS – steel (cast iron)

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Hydraulic three-way valve “L” with NPT female thread, type SK3L

List of product variants

Additional information

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Related Products

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