Freeze-resistant metering valve
AssigneeHydraulik-Ring GmbH
InventorsDieter Maisch, Stefan Klotz, Matthias Bleeck
Life of this patent
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Abstract
A freeze-resistant metering valve is provided that comprises a magnetic part and a hydraulic part. The magnetic part has an armature biased by a spring. The hydraulic part has an annular space for receiving and conveying a liquid as well as a tappet facing a valve seat. The valve seat comprises a nozzle opening on the side facing away from the tappet. In a currentless state, the tappet blocks the annular space in the direction of an opening (nozzle opening) until a freezing pressure exerted onto the armature generates a sufficient force by virtue of the solidifying liquid. This force is used to counteract the spring force until a freeze expansion space is created by way of a relieving motion.
Claims20
A freeze-resistant metering valve, comprising:
- a magnetic part and a hydraulic part;
- the magnetic part having an armature biased by a spring;
- the hydraulic part having an annular space for receiving and conveying a urea-water solution and a tappet facing a valve seat, the annular space extending along at least a portion of the tappet;
- and
- the valve seat having a nozzle opening,
- wherein:
- the metering valve is itself passively relieved during freezing of the urea-water solution;
- a length of the annular space is created such that the magnetic part is positioned in a markedly lower temperature range than an end piece of the hydraulic part of the valve;
- the urea-water solution is introduced into an exhaust gas stream without use of compressed air;
- and
- an outlet is provided as a further opening in a vicinity of the nozzle opening, the further opening enabling a constant circulation of the urea-water solution such that the hydraulic part is cooled by the urea-water solution.
Dependencies are inferred from the claim text.