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Constant Gas Flow Using Pressure Regulator

10/12/2016 5:19 AM

I have installed an Elster American Meter Co Gas Pressure Regulator at one of my client's site. The problem is that whenever the inlet pressure increases, usually it fluctuates from 12 psig to 45 psig, the outlet pressure remains the same, set at 2.75 psig, but the flow rate of the gas increases, and the chimney of the furnace starts giving black smoke due to more gas into the system, the air is fixed, its a natural draft sodium sillicate regenerative furnace. So what they do is, that they just adjust the pressure from the regulator everytime to avoid black smoke. What I am going to do now, inorder to prevent re-adjusting of the regulator every time, is that i will install a tube downstream to measure the total pressure (static + dynamics) and feed that back to the regulator, and if this total pressure is constant, I will get a constant gas flow rate whatever the inlet pressure may be.

I need sugestion, if it sounds a feasible idea. Will it work?

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#1

Re: Constant Gas Flow using Pressure Regulator

10/12/2016 6:04 AM

You can't obtain constant flowrate by maintaining the pressure constant, as you have seen.

What is wanted is oxygen trim control. Modulate the gas flowrate to obtain minimum excess oxygen in the stack. That way, smoke, an indication of too much fuel, will be minimised. If in doubt, consult the furnace manufacturer for more information.

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#4
In reply to #1

Re: Constant Gas Flow using Pressure Regulator

10/12/2016 11:27 AM

the static pressure remains constant. thats what the regulator do, it maintains the static pressure, but the dynamics pressure increases with the increase in main line pressure, upstream, and hence the gas flow rate increases. I am using a pitot tube type concept to measure the total pressure the the outlet of regulator, and will feed that back to diaphragm of the regulator. that will maintain a constant total pressure. and hence a constant volume flow rate.

we dont want to use oxygen trim its way to expensive.

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#6
In reply to #4

Re: Constant Gas Flow using Pressure Regulator

10/12/2016 11:33 AM

Then you haven't got constant flow. The starting point for this thread is false.

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#8
In reply to #6

Re: Constant Gas Flow using Pressure Regulator

10/12/2016 1:35 PM

I NEED CONSTANT FLOW RATE! That was the starting point of this thread. Currently i am facing the problem of variable flow rate, i need to have constant flow rate, by only using a gas pressure regulator

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#22
In reply to #8

Re: Constant Gas Flow using Pressure Regulator

10/13/2016 4:33 AM

So you said earlier. I did read it. You're not going to get what you want with the installation that you have.

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#45
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Re: Constant Gas Flow using Pressure Regulator

10/15/2016 1:33 AM

we live in a rational world. Reply with a REASONING!!!

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#26
In reply to #8

Re: Constant Gas Flow using Pressure Regulator

10/13/2016 10:07 AM

Last time I checked, a gas pressure regulator has nothing in particular to do with the flow rate in the system, other that establishing wide limits of flow. It has nothing to do with constant flow. Apparently, what we have here is another failure to communicate.

Do you experiment, but remain quiet until you have proof your idea works.

And do please stop insulting the very astute and capable members of this forum. You are not a superior being, and apparently are not a particularly smart one.

Here: Take a read, and go sip some warm tea with butter under a fig tree until you release your guile and vitriol, and learn to love others as you would have them love you.

gas service pressure regulators

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#48
In reply to #26

Re: Constant Gas Flow using Pressure Regulator

10/15/2016 1:51 AM

I apologize, if you feel that way, but i didn't mean anything like that.

You can see the data sheet you have attached yourself which clearly says, that if inlet pressure increases, the flow rate would eventually increase. You are right, i must try my idea, and check how it goes.

thanks

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#55
In reply to #48

Re: Constant Gas Flow using Pressure Regulator

10/17/2016 11:46 AM

Typically, here in the United States, there are always at least two regulators, one on the down let pressure from the main gas line, and a second near the burner controls (of a boiler for example).

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#37
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Re: Constant Gas Flow using Pressure Regulator

10/14/2016 5:11 AM

But if the system adjusts things to keep flow constant, the dynamic pressure is constant, so no need to adjust for it.

In any case, at a typical velocity 5 m/s, and gas density 0.8 kg/m3, pressure 0.5*ρ*V2 ~ 10 Pa = 1 mm wg. 2.75 psi is ~ 1900 mm wg, so dynamic pressure likely to be negligible.

Sounds like you have a sophisticated regulator if it can accept control inputs, e.g. 4 - 20 ma. Usually these things are self-actuating, with an adjustment knob.

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#50
In reply to #37

Re: Constant Gas Flow using Pressure Regulator

10/15/2016 2:06 AM

the flow is around 12000 to 13000 cubic ft per hour in a 2 Inch 40 SCH pipe. Any regulator data sheets says that increase in inlet pressure will cause increase in flow rate, and if the static pressure downstream remains the same, obviously there is an increase in the dynamic pressure, which we dont want to increase.

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#2

Re: Constant Gas Flow using Pressure Regulator

10/12/2016 7:37 AM

Do you have a gauge on the downstream pressure? If so, does it remain steady?

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#5
In reply to #2

Re: Constant Gas Flow using Pressure Regulator

10/12/2016 11:30 AM

Yeah there is a gauge downstream. it remains steady. when the gas burner jets are open the the gauge shows 2.75 psig. and when the the valves are closed the gauge shows 5 psig. there is no intermediate position of the valves.

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#36
In reply to #5

Re: Constant Gas Flow using Pressure Regulator

10/14/2016 4:36 AM

There's something odd here. If the system characteristics downstream of the regulator are fixed (which would be the case with a burner), and the regulator downstream pressure stays constant at 2.75 psig, the flow should be constant.

It's probably irrelevant that the pressure rises to 5 psig when the burner valve is closed, but regulators are available which give constant outlet pressure at zero flow, bleed-off type or something if I remember right.

Is the regulator rated for inlet pressure 45 psig?

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#39
In reply to #36

Re: Constant Gas Flow using Pressure Regulator

10/14/2016 9:49 AM

With natural gas, one wants to not have any venting due to pressure changes, for the simple requirements of equipment safety.

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#41
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Re: Constant Gas Flow using Pressure Regulator

10/14/2016 10:20 AM

Yes, I suppose it would have to bleed to atmosphere. I haven't dealt with these things for some years. But if there's a pressure relief (I think there is on some of the regulator models in the link on your #26, but I haven't time to reopen it) that would discharge to somewhere appropriate, and bleed-off could go into same line.

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#40
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Re: Constant Gas Flow using Pressure Regulator

10/14/2016 9:56 AM

That makes the situation obvious: Upstream supply is wildly swinging, perhaps due to your furnace operation, but more likely due to other local users with high demand on the system.

You must employ the second regulator on the upstream feed side, so that your 2.74 psig regulator never sees an inlet pressure higher than 12 psig. The condition of pressure during no flow is no consequence to furnace operation whatsoever.

Once you establish constant pressure on the furnace inlet gauge, nothing should change, you should have near constant flow, controlled combustion ratios, etc., and no more smoke, unless someone is throwing a dead pig into the furnace.

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#52
In reply to #5

Re: Constant Gas Flow using Pressure Regulator

10/16/2016 1:25 PM

"when the gas burner jets are open the the gauge shows 2.75 psig. and when the the valves are closed the gauge shows 5 psig. "

It should be obvious what your problem is related to right there.

Your regulator is set for 5 PSI not 2.75 and you are only getting the 2.75 PSI output pressure due to excessive internal restriction of the regulator due to it being undersized or the gas flow you require.

More than likely when running below the 40 PSI inputs the regulator can not pass enough volume through its internal metering valve and thusly you get the 2.75 PSI output but once the input pressure is high enough it can push more gas though thus raising the output pressure above the 2.75 PSI value eventually reaching someplace near its 5 PSI setpoint.

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#56
In reply to #52

Re: Constant Gas Flow using Pressure Regulator

10/17/2016 2:55 PM

Good point, I'd noticed that, velocity is very high for gas supply. I meant to ask OP if the pipework is run in same size as the 2" regulator, but forgot. I'd be surprised if the gas inlet flange on the burner is 2", more likely 4". Perhaps he'll come back.

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#58
In reply to #52

Re: Constant Gas Flow using Pressure Regulator

11/08/2016 7:50 AM

"when the gas burner jets are open the the gauge shows 2.75 psig. and when the the valves are closed the gauge shows 5 psig."

That is normal operation for direct acting pressure regulators. The pressure above the setpoint is called Lock-up, as shown below in a characteristic pressure vs flow performance chart:


Standard adjustment procedure is to adjust the operating pressure at some nominal flow rate, not at no-flow conditions, because the no-flow lock-up pressure is higher than flowing conditions.

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#3

Re: Constant Gas Flow using Pressure Regulator

10/12/2016 11:17 AM

WE won't know until YOU try it.

They are your client, you are being g paid to make it work.

Call the manufacturer!

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#9
In reply to #3

Re: Constant Gas Flow using Pressure Regulator

10/12/2016 1:38 PM

I was seeking a suggestion on the proposed solution i have thought of. Installing a pitot tube to determine the total pressure (static +dynamic) right after the regulator, and feed it back to the regulator diaphragm.

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#11
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Re: Constant Gas Flow using Pressure Regulator

10/12/2016 1:50 PM

Try it, and report back, but make sure the feedback is negative, so that increasing the signal dynamic pressure will reduce the static pressure at the regulator, or something to that effect. There are more elegant solutions to flow regulation, and it usually requires a direct measurement and a control valve.

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#14
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Re: Constant Gas Flow using Pressure Regulator

10/12/2016 2:13 PM

Yeah, I will definitely try it. Yes you are right. Adding the dynamic pressure signal will reduce the static pressure at the regulator, but we will re-adjust from the spring to get the required flow rate of the gas, the good part is that if the main line pressure rises from 12 psig to 40 psig the total pressure at the outlet of regulator will remain constant. Hence i am quite positive that we maintain a constant flow with this technique. Alternatively i have used a Pressure Transmitter upstream which give a 4-20 mA control signal, which i have used to control a motorized butterfly valve downstream. The problem with this system is Fine Tuning, primarily.

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#18
In reply to #14

Re: Constant Gas Flow using Pressure Regulator

10/12/2016 3:25 PM

Why not use a doggone flow transmitter?

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#20
In reply to #18

Re: Constant Gas Flow using Pressure Regulator

10/13/2016 2:10 AM

If we use flow transmitter, we will have to use an orifice, nozzel, or venturi to attach it to...adding more complexity to the system. And rather than doing this, we would simply buy a mass flow controller and attach it to the gas line, which will have all the things included in it. I am going to try that dynamic pressure feedback thing, and lets hope it works..and if it does, nothing would make me more happy, and I am sure its not a bogus idea to implement.

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#33
In reply to #3

Re: Constant Gas Flow using Pressure Regulator

10/13/2016 8:01 PM

If you had ever solved this problem, you would know the answer. But you have not, nor have I, and the OP doesn't need either of us to tell him that we don't know. Someone may have knowledge that you and I don't posses, and the fact that your ignorance on the subject compels you to be an asshole over and over and over is so tiresome. Where do you get the stamina?

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#7

Re: Constant Gas Flow Using Pressure Regulator

10/12/2016 1:30 PM

The real question is why is the clients' supply pressure swinging so wildly? Can your furnace operate with 12 psig? If so, then why not install a pressure regulator upstream of the 2.75 psig regulator, and set the upstream one on 12.5 psig. It sounds like you need to control the supply to the system before you can control furnace supply.

Just a wild guess.

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#10
In reply to #7

Re: Constant Gas Flow Using Pressure Regulator

10/12/2016 1:48 PM

The supply pressure fluctuation is really not client's fault. Its Natural Gas Supply Company's fault. Sometimes the supply pressure is around 12 psig, and some times its 40 psig. We cannot change.

Installing double regulators, was also an option on the table, but the problem will remain there, because once the main supply pressure increases from 12 psig to say 40 psig, the flow rate will eventually increase.

My point is, what if we using a pitot tube downstream right after the regulator, use that total pressure (static +dynamic) to control the diaphragm of the regulator. Pressure regulators are always designed for static pressure, so why dont we try to utillize the total pressure upstream

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#12
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Re: Constant Gas Flow Using Pressure Regulator

10/12/2016 1:52 PM

You do understand that flow usually reduces the dynamic pressure on a system?

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#13
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Re: Constant Gas Flow Using Pressure Regulator

10/12/2016 2:07 PM

Well, what I have learned in Fluid Dynamics Course at engineering, the flow reduces the static pressure. For example, if we have a tank full of compressed air, 40 psig, which is the static pressure = total pressure with no flow. now if we connect a hose pipe to the tank and open the valve, the tank pressure will remain 40 psig, but in the pipe where the area is less and velocity is high so the static pressure is less tan 40 psig, and the part of total pressure is converted into dynamic pressure. Higher the flow, higher the dynamic pressure at any given point.

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#19
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Re: Constant Gas Flow Using Pressure Regulator

10/12/2016 3:27 PM

Not necessarily true, since the Bernoulli effect can even produce negative pressure.

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#15

Re: Constant Gas Flow Using Pressure Regulator

10/12/2016 2:18 PM

I've never seen a furnace or any kind of gas appliance that didn't have a pressure regulator upstream of the equipment(~15psi) for the main line and another regulator at the device for final pressure feed.....

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#16
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Re: Constant Gas Flow Using Pressure Regulator

10/12/2016 2:32 PM

So you are saying that we must have one regulator on the mainline, that provides 15 psig or 1 bar and then we must have another regulator that reduces 15 psig to 3 psig at the point of use. But say even if we have two regulators, the problem still remains the same, the mainline pressure will increase upto 40 psig, which will increase the dynamic pressure, although the static pressure remains the same after each regulator, but the flow has increased due to increase on dynamics pressure, which is coming from increase in mainline gas pressure rising to 40 psig.

People usually use multiple regulator concept because its costly to install a high pressure regulator for each appliance, what they do is that they install a high pressure regulator on the mainline, and use low pressure regulators for appliances or furnaces installed after that for individual control, But here its just the mainline, and the furnace, so we can have only One Regulator working for us.

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#17
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Re: Constant Gas Flow Using Pressure Regulator

10/12/2016 2:41 PM

The first regulator is to step down pressure and provide constant velocity to the second regulator which is sized according to the line size which is sized according to the appliance demand which determines the second regulator size...

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#21

Re: Constant Gas Flow Using Pressure Regulator

10/13/2016 4:31 AM

So, why is the furnace manufacturer not involved so far?

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#23

Re: Constant Gas Flow Using Pressure Regulator

10/13/2016 5:10 AM

Unless your regulator is malfunctioning (failing to give constant downstream pressure), then everything thereafter will give constant flow. You are overthinking (and thereby underthinking) everything about this.

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#46
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Re: Constant Gas Flow Using Pressure Regulator

10/15/2016 1:35 AM

The regulator is not malfunctioning, if you come across a data sheet of a regulator it will tell you that for a constant downstream pressure, the flow rate increases with the increase in upstream pressure.

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#53
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Re: Constant Gas Flow Using Pressure Regulator

10/17/2016 10:33 AM

I don't know what data sheet you've looked at, but that isn't right. A simple throttle would give that characteristic. The function of a pressure regulator is to maintain constant downstream pressure, irrespective of changes in upstream pressure and downstream resistance, within the regulator design range. (that would be ideal, in practice downstream pressure unlikely to be exactly constant). Also explained in Iris's #51.

As I said in #43, at a given inlet pressure, reducing downstream resistance gives increase in flow, at constant pressure (ideally), up to a point, after which the pressure falls rapidly (the internals being wide open), and the flow reaches a maximum when the outlet is open to atmosphere. If that is repeated at a higher inlet pressure (same set pressure) the pressure fall-off occurs at a higher flow. Maybe that's what you're thinking of. But it's irrelevant if the regulator has been correctly selected for the proposed duty.

I realise that doesn't solve your problem. From the link in Iris's #51, depending which orifice is fitted it seems possible the regulator is borderline sized, but that still wouldn't explain why the flow has increased if, as you say, the downstream pressure has not increased. The pressure/flow characteristic of the burner doesn't change, unless there's something you haven't told us. Are you sure your pressure gauge is accurate? If in doubt I would rig up a water manometer, easy to do and can't be argued with!

As you said earlier, you could use a control valve, flow meter and controller (with PID to eliminate droop) but that would be more expense, and isn't usually necessary for boiler supply.

Let us know how you get on.

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#54
In reply to #53

Re: Constant Gas Flow Using Pressure Regulator

10/17/2016 11:39 AM

I'm suspecting the being undersized since he says in post 5 that when the valve to the burner is shut off the output pressure goes up to 5 PSI.

Also given the high volume gas flow through the line if the gauge is connected at a 90 degree tap onto the line (like any typical pipefitter would do) it's not likely to be all that accurate either being the gauge port into the main line could very well be experiencing high degree of venturi effects that are giving it a false reading well below what the actual pressure is inside the main line.

Output pressure could go up yet the increased flow past the gauge port and a venturi effect in play could counteract the gauge reading from going up so even though there was a considerable volume increase (as his burner flame shows to be happening) the gauge itself could very well show no change as he is saying.

If you do the numbers 12 - 13,000 CFH through a 2" line is a working velocity of ~150 - 170 feet per second which in my books would be capable of a substantial venturi effects given any hole in the wall of the pipe!

That's what I have suspicions of.

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#24

Re: Constant Gas Flow Using Pressure Regulator

10/13/2016 7:21 AM

Which model Elster regulator?

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#47
In reply to #24

Re: Constant Gas Flow Using Pressure Regulator

10/15/2016 1:36 AM

its Elster American Meter Co 1803 with internal static connection. Size DN50

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#25

Re: Constant Gas Flow Using Pressure Regulator

10/13/2016 9:55 AM

Have you considered that the black smoke may be from the quality or mix ratios of their fuel supply changing?

Natural Gas suppliers add air to their fuel delivery to change its effective thermal content per unit of volume in order to adjust for different amounts of other combustible or noncombustible gases that may be present in the supply and in many cases some do it to simply cheat the customer into having to buy more gas than they need as well.

Whats in utility supply gas.

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#27
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Re: Constant Gas Flow Using Pressure Regulator

10/13/2016 10:35 AM

I would have less confidence in natural gas supplies in Pakistan, but the OP never stated this was natural gas, or unnatural gas. It could be something really, really bad, of varying BTU content, or even of widely varying ratios being saturated gases as methane, and unsaturated gases such as ethene, acetylene, etc. It might even be refinery off-gas that could include BTEX as vapors. Who knows what they really are burning?

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#28
In reply to #27

Re: Constant Gas Flow Using Pressure Regulator

10/13/2016 10:40 AM

I understand completely but he doesn't 'so it has to be the regulators fault' being that's adjustable on his end and appears to correct the problem.

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#35
In reply to #27

Re: Constant Gas Flow Using Pressure Regulator

10/14/2016 4:24 AM

He said natural gas in #10. What that means in Pakistan I've no idea!

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#49
In reply to #27

Re: Constant Gas Flow Using Pressure Regulator

10/15/2016 1:52 AM

dont worry, nothing like that. Fixed BTU per Cubic Ft. and its 95% Methane

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#29

Re: Constant Gas Flow Using Pressure Regulator

10/13/2016 11:03 AM

By far the easiest and cheapest solution is to go to a stack gas oxygen sensor and throttle control the fuel supply to maintain oxygen concentration in the exhaust gas.

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#30

Re: Constant Gas Flow Using Pressure Regulator

10/13/2016 11:17 AM

A second, bulletproof method would be to regulate into a buffer tank at 12.5 psi. Take the buffer tank output and feed it to the existing regulator, which becomes a static setting throttle valve.

The problem you describe is one I have seen in pressure reliefs and regulators in that the existing valve has hysteresis due to internal component friction and a feature called accumulation due to dynamic gas flow and internal surface area configuration. This is built into the regulator and the only solution is to go to a different valve with a different internal design and geometry. Sensing line geometry and location has been mentioned by others already. It is not reasonable to expect a single stage, garden variety regulator to cope well with a 300% swing in inlet pressure.

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#34
In reply to #30

Re: Constant Gas Flow Using Pressure Regulator

10/13/2016 11:26 PM

Why?

The LPG regulator on my house, and most BBQ grills, puts out 10" - 11"s WC with a input range of 2 - 315 PSI as single stage units.

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#38
In reply to #34

Re: Constant Gas Flow Using Pressure Regulator

10/14/2016 9:45 AM

I would be willing to bet real money (about $0.25 in my pocket), that your source pressure is really steady. Especially since it runs off old tires.

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#42
In reply to #38

Re: Constant Gas Flow Using Pressure Regulator

10/14/2016 11:48 AM

The house furnace uses regular propane from a tank like everyone else's. It's the backup heating system.

The tires go in the shop boiler for fuel for the hot water heating system that does the primary heating.

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#31

Re: Constant Gas Flow Using Pressure Regulator

10/13/2016 11:22 AM

MFC- mass flow controller. this seems like a simple fix. Perhaps you should look this up.

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#32

Re: Constant Gas Flow Using Pressure Regulator

10/13/2016 2:50 PM

What you want has an interesting parallel with anaesthetic machines. This are supplied by a regulator at 4 bar, although the sorts of pressure a human lung tolerates are measured in cm of H2O. The needle valve at the bottom of the flowmeter acts as a very high resistance, so as soon as there is flow, the pressure at the outlet is dropped to safe levels. There is a second effect, though. There is a high pressure applied to the top of a high resistance. If you do this with volts and high ohms, varying any further resistance has little effect on the flow, i.e. it becomes a constant-current source. If you do the same thing with a high pressure regulator and a length of thin tubing to act as a restrictor, you will end up with a constant flow.

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#43

Re: Constant Gas Flow Using Pressure Regulator

10/14/2016 1:00 PM

Looking at this again I notice you say set at at 2.75 psig. But what is the actual downstream pressure when the inlet pressure varies?

The regulator curve, plotting flow horizontal and outlet pressure vertical, at a given inlet pressure should show constant pressure (horizontal line) as the downstream resistance falls (on a test setup) up to a point, after which the pressure starts to fall, going to near zero if the outlet is opened wide. At a higher inlet pressure it's similar, initial pressure as before, but the pressure drop-off occurs at a higher flow. And higher still for higher pressures.

If you're not sure about downstream pressure, it's possible that with 12 psig inlet you're on the falling part of the curve, but higher inlet pressure takes you back to the horizontal bit, at higher flow. Specially if the regulator size is borderline for the flow required.

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#44
In reply to #43

Re: Constant Gas Flow Using Pressure Regulator

10/15/2016 1:29 AM

Thank you for a serious feed back. The downstream pressure remains steady at 2.75 psig. The PROBLEM is that the INLET PRESSURE DOES NOT REMAINS CONSTANT. We need a constant flow at 12 psig inlet pressure and 40 psig inlet pressure, and whats in between. I hope you get it. My concept was to utilize the TOTAL PRESSURE (dynamic +static) downstream and feed it back to the regulator.

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#51

Re: Constant Gas Flow Using Pressure Regulator

10/15/2016 11:49 AM

Elster 1803, 2" (DN50) regulator

1) Be aware that any mechanical pressure gauge is subject to damage when over pressured. Is the gauge responding in a linear fashion (the pointer is not stuck at some fixed position due to having been overpressured?) at a reasonable accuracy?

2) A pressure regulator maintains sensed downstream pressure and attempts to hold it constant, regardless of upstream pressure, within its design operating limits. It does that by regulating the flow through the orifice. It is a regulating valve.

It does so in a proportional-only fashion, meaning that there is some droop (drop off in pressure regulation) as the flow increases. Droop is always in a negative direction (lower maintained pressure), never in a positive direction.

3) Flow rate is determined by the downstream demand (how many devices consume volume). If the demand is constant, the flow at a constant pressure is constant. If the demand varies, the regulator adjusts flow to maintains the outlet pressure as closely to its setpoint as it can.

The implication is that a pressure regulator can maintain a constant pressure (minus droop) but it does not maintain a constant flow rate, it is not a differential relay (a constant flow regulator). This is physics.

4) Regulators need to be sized for the expected flow rate and required pressure. There are a variety of orifices and spring ranges used to accomplish matching the required flow rate and pressure.

The manual at this link
http://www.elster-americanmeter.com/assets/products/products_elster_files/SB8540.pdf

shows tables with the variety of combined orifices and springs.

The 1803 DN50 (2 inch) with a spring for 2-3 psi outlet pressure sizing table (page 9, SB 8540.3) is shown below:

If the valve orifice is 7/8" (depending on holder), or 1" or 1 1/4", then the 45 psi supply pressure exceeds the operating limit as shown by the solid black line. A 2nd upstream 'knockdown' regulator with sufficient flow capacity would be needed.

5) If the pressure gauge indicates a steady pressure, the regulator is doing its job, maintaining down stream pressure. It does that by regulating the flow through the orifice valve.

6) Given the conditions above, either
- the regulator is not functioning correctly. It is not holding a constant downstream pressure with varying upstream pressures due to
* incorrect sizing
* internal malfunction
- or the regulator is working properly but something is varying downstream of the regulator to create a periodic gas rich/combustion air starvation condition.

7a) How do you know this regulator is sized correctly for the flow rate at the pressure required?

7b) Is the combustion air adequate? Is the combustion air being choked?

7c) The internals determine the pressure regulation ability. Have you checked the ID tag on the unit to confirm the correct spring and orifice for this application (assuming you know the required flow rate for the burners)?

Springs and orifices are replaceable. Could the internals have been replaced and not identified properly? (used regulator?)

http://www.kinggageengineering.com/Portals/0/Products/Manuals/Elster%20American%201800-2000%20IOM.pdf

The IOM's (Installation Operating Manual) parts list shows that the springs are color coded.

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#57

Re: Constant Gas Flow Using Pressure Regulator

10/21/2016 9:01 AM

Are you thinking of letting the forum know if and how the problem has been solved?

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