Hydraulic Hose Burst Valves

Hydraulic Hose Burst Valves
I have talked many times about my dislike for Hose Burst valves (velocity fuse).
A cheap and nasty little valve that screws directly into the cylinder port and should close when the velocity across the valve exceeds the spring setting.
So why do I hate this valve so much?
Many unwitting users do not realise that these valves must be properly adjusted using feeler gauges if they have any chance of them working properly. The manufacturer should supply a chart with the valve showing a valve gap dimension based on flow. This is not the flow of the pump but the flow that will pass from the cylinder under normal conditions and is calculated using the displacement volume of the ram and its velocity.
The valve will not compensate for any change in temperature or load and can often close when operating under normal conditions, causing annoying stoppages. However the main purpose is that they must close should a pipe or hose burst. If the worst happens and the valve does not close, the result can be catastrophic and cause serious damage or injury.
If you are serious about protecting against hose burst then spend a little more money and do the job properly using a Pilot Operated Check valve. It will react instantly and must be built in as part of the cylinder with no pipe between the cylinder port and valve except for the pilot. This is a better quality valve and much more reliable.
Always keep in mind that there is NO complete failsafe way of hydraulically holding up any load with a ram except by using mechanical locking. Even if a new installation initially holds well, time and wear will eventually increase leakage and the load will creep down.
Be safe.
Bob Jackson (The Hydraulicman)
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