HAM-LET® H-300 Integral Bonnet Needle Valves

The Ham-Let® H-300U Series is an advanced high pressure instrumentation needle valve for shut-off service, its packing bolt design for easy mounting being the best solution for instrumentation panels.

This compact valve enables relatively high level of flow regulation and long-life service. Special stem surface treatment, based on low temperature carbon diffusion, enables higher surface hardness with improved wear resistance, resistance to system contaminations and optimal operational torque.

The H-300U was designed for high pressure services were moderately uncontaminated media is used.

For steam applications, it is recommended to select one of Ham-Let severe service needle valves.

For relatively high pressure pure oxygen applications, assure that the selected valve is tested and found to meet the specific application requirements.

The H-300U are available with a choice of stem tips:

  • Regulating: Used where some degree of flow control is required.
  • V-Stem: Standard stem tip used for on/off operation in general-purpose liquids and gas service.
  • Non-Rotating: Typically used in high-cycle applications to extend valve life and prevent stem rotation inside the body tip, a suitable selection for gaseous high pressure applications.
  • Soft seat: soft seat tip requires lower seating torque than a metal stem tip; the best choice for clean gaseous high pressure applications. Maximum allowable working temperature is 200°F (93°C).


  • The H-300U design has been tested for Burst and Proof.
  • Every H-300U valve is factory tested with nitrogen at 1000 psig.
  • Maximum allowable leakage across the seat is 0.1 std cc/min.

Packing Adjustment:

  • Due to the varied service applications of the valve, packing adjustment may occasionally be necessary.
  • Packing is factory adjusted to 1000 psig service. Initial packing adjustment is recommended after installation and prior to start-up.
  • Please see packing adjustment procedure for more details.

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