Flowmeter type of the fuel oil supply/return for heater

[1906]

Recently we experience two operational difficulties for the heater operation.
One is the malfunction fuel oil return ovalmeter which increased fuel oil supply pressure suddenly. Promptly O2 showed almost o% by the increased of oil pressure and increased fuel oil flow.
The other was sudden stop of fuel oil supply ovalmeter thus heater fuel oil was not supplied for the time being.
Based on above experience, we suspect ovalmeter in heater operation seems not good design philosophy. Rather than simple orifice type looks better except acuracy.
If there is anyone who knows well about recent design trend of oil flowmeter type for heater fuel oil measuring, let me have that recent concept and knowledge.

 

[jmw]

You might visit the FTI web site,
Their gear type flow meters are specifically designed for fuel flow to burners and engines and in order not to starve the burner or engine due to a flowmeter fault they have extra clearances.
This goes somewhat against the idea of a PD meter but they do calibrate them across a range of viscosities so that they can correct for the higher slip flows as they change with viscosity.

I suggest this is largely a feature for the cautious as the history of fuel oil meters does not suggest this is a problem.
Rotary piston meters, sliding vane meters, multi-piston meters and gear meters (without any special clearances) have been used with burner fuels of various grades (from light domestic oil to heavy fuel oil) with no significant problems.
Indeed, they have even been used with bitumens and tars.

The meters should not be used outside their design temperature range and so if you change from light oil to heavy oil at a higher temperature you will find some problems possible, the clearances are very much dictated by the expected temperature of operation.
It is also necessary to make sure the fuel is as clean as it is supposed to be. Many PD meters are happy enough with 80mesh filters, but they do need this level of filtration (or as specified by the manufacturer) and there is sometimes a tendency for operators to omit replacing filter screens so that they don't have to come and change them again. Some meters have integral filters but same operator problem.

In other words, the benefits of these technologies are valued and if you have a problem then let's find the problem before we condemn a whole class of meters that has successfully been used for many decades for these applications. This is particularly true of engines since any particulates that will kill the meter are also not so good for the engines. Burner operators are less fussy.

SO, what is the history of these meters? are they new in a new installation?
Are they properly protected by filters (and are the screens fitted)?
ARe they on the duty they were supplied for?
Has anything changed in the installation or operation since they were originally installed? Have there been any significant "events" recently that might impact on the meters?

JMW

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