Mechanical vs. Displacement/hydrostatic lubricators

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Benjamin Maggi
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Mechanical vs. Displacement/hydrostatic lubricators

Post by Benjamin Maggi »

I am not to that point yet but I was trying to do some research on which type of lubricator would be best for our live steam models- specifically, those large enough to run on 7.xx" gauge track. My Sweet William plans show provisions for mechanical lubricators but actual prints for displacement lubricators, so it is builder's choice. I like the functionality of mechanical ones but don't really like their appearance, whether driven off the cross head or some other part of the valve gear. I do like the novelty of putting displacement lubricators in the engine cab and sort of "hiding" them from view because they then don't clutter the clean lines of the engine.

It seems that most people in the larger scales use mechanical ones. Is there a reason for this? Will displacement ones fill up with water too quickly and require constant draining, or are they hard to regulate the amount of oil that is passed through?

Note: regardless of type I do plan to install two separate lubricators, one for each cylinder, to ensure that both get oil.
"One cannot learn to swim without getting his feet wet." - Benjamin Maggi
- Building: 7.25" gauge "Sweet Pea" named "Catherine"
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Fred_V
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Re: Mechanical vs. Displacement/hydrostatic lubricators

Post by Fred_V »

It is a matter of preference. I think hydrostatics can be fussy sometimes. On mechanical ones I used one that has sprag clutches on the lever arm rather than the ratchet. With this the lever has to move farther to engage the next stroke than the ratchet does. This limits how slow you can make it pump.

Mine over pumped a bit. The clutches have so little resistance that you cannot use a slotted rod to slow the stroke.
Fred V
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Bill Shields
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Re: Mechanical vs. Displacement/hydrostatic lubricators

Post by Bill Shields »

hydrostatics as designed by Bill Van B always work and never have problems.

I added a sliding separator to keep all of the water separated from the oil, but it really is not necessary...

hide them under your running board as an air tank and forget about them for the weekend.
Too many things going on to bother listing them.
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gwrdriver
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Re: Mechanical vs. Displacement/hydrostatic lubricators

Post by gwrdriver »

Ben,
The long-observed preference for lubricators is hydrostatic (more correctly "displacement") lubricators for 2.5"ga/Ga3 and below, and mechanical lubricators for 3.5" gauge and above. One consideration is of course physical space. A functioning displacement lubricator can be made very small and can be installed on very small locomotives. Not so much mechanical lubricators. The main thinking however (well, my thinking anyway) is that the larger the locomotive the more important it is to insure it has reliable cylinder lubrication. Unless they are made with metering capability displacement lubricators can be erratic and can either put out far to little or far too much oil, neither of which will cause much damage on a small scale loco if tended to early. Mechanical lubricators on the other hand can be made to be very reliable (if you get the feed ratchet or 1-way roller clutch right) and with a consistent controllable metered delivery. For me it's the reliability and metering capability that is important to have on a large scale loco.

Edit - My first mentor, Paul Brien, tried a pair of LBSC-designed true hydrostatic lubricators on this first locomotive, a 7.5"ga 0-6-0. These had water-filled gauge glasses mounted in the cab. The metered oil dripped Up through the glasses. He was never able to get this setup to work reliably, and he had also tried a couple of other LBSC "guaranteed to work" details on this loco which didn't work either, so he abandoned the hydrostatic setup in favor of mechanical lubricators.
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bcody
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Re: Mechanical vs. Displacement/hydrostatic lubricators

Post by bcody »

I run a Bill Conner designed/built 4+4 Beam Engine which has a mechanical lubricator consisting of two cylinders (with pistons) mounted side by side and interconnected with a beam pivoted 1/4" off center to give the steam cylinder a mechanical advantage. Piping - Oil cylinder is piped to a fitting in the steam line to the locomotive cylinders (after the throttle) through a needle valve for flow rate adjustment. The other (steam) cylinder is piped directly to the steam line from the throttle upstream of the oil connection. Operation - As you apply steam to run you are also applying steam to the lubricator steam cylinder which pressurizes the oil cylinder causing regulated oil flow to the steam line going to the locomotive cylinders. Oil flow rate is proportional to the amount of throttle applied. During the day you check the beam position to determine if you need to add oil. When oil is needed you fill the oil cylinder with a pump type oil can through a check valve in the top of the oil cylinder. This filling of the oil cylinder causes the beam to force the steam cylinder piston back, displacing the water in the cylinder to the steam line going to the locomotive cylinders. I have been running this lubricator since 2001 with no problems, I dialed mine in in 2001 and since then I just keep it full of oil and forget it. Both cylinders are about one inch in diameter x one inch long and I refill after 1-2 hours of running. My locomotive cylinders are 2"x2.75" driving 4.375" drivers through a 20% overdrive.
And yes, I do have enough power and speed to run away and hide if I wish as well as pull a train with 11 preschool children and 12 adults.

Bill
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Fender
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Re: Mechanical vs. Displacement/hydrostatic lubricators

Post by Fender »

Somewhere I've seen pictures of an actual hydrostatic (not a displacement) lubricator on a 2.5" scale loco. It uses glycerin as the medium the oil drops rise through.
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Rwilliams
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Re: Mechanical vs. Displacement/hydrostatic lubricators

Post by Rwilliams »

The mechanical lubricator allows one to have a reliable source of lubrication and keep the oil mess out of the cab.

In full size, even the Bullseye lubricators in the cab are well known for all the connections and leaks. I have seen quite a few of them in 2.5 scale and they do look great in a well detailed cab. Problem is the small ones in 2.5 scale always seem to leak profusely and the area around them is always an oily mess. Saw one in 1.5 scale years ago and it too had the signature oil coating.

I have often felt that a good mechanical lubricator is the most wise choice to go with. If one must have full cab detail, employ a dummy Bullseye lubricator in the cab for visual effect and zero oil mess. Problem is no one has offered a nice dummy Bullseye lubricator in 1.5 scale for this option. With the luxury of metal RP machines today, perhaps someone will step to the plate and solve this long missing link to our hobby.
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cbrew
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Re: Mechanical vs. Displacement/hydrostatic lubricators

Post by cbrew »

Fender wrote:Somewhere I've seen pictures of an actual hydrostatic (not a displacement) lubricator on a 2.5" scale loco. It uses glycerin as the medium the oil drops rise through.
that would be the K36s at Tom Millers.
seem them with my own eyes :)
If it is not live steam. its not worth it.
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Fred_V
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Re: Mechanical vs. Displacement/hydrostatic lubricators

Post by Fred_V »

bcody wrote:I run a Bill Conner designed/built 4+4 Beam Engine which has a mechanical lubricator consisting of two cylinders (with pistons) mounted side by side and interconnected with a beam pivoted 1/4" off center to give the steam cylinder a mechanical advantage. Piping - Oil cylinder is piped to a fitting in the steam line to the locomotive cylinders (after the throttle) through a needle valve for flow rate adjustment. The other (steam) cylinder is piped directly to the steam line from the throttle upstream of the oil connection. Operation - As you apply steam to run you are also applying steam to the lubricator steam cylinder which pressurizes the oil cylinder causing regulated oil flow to the steam line going to the locomotive cylinders. Oil flow rate is proportional to the amount of throttle applied.

Bill
Oil flow is not proportional to throttle but rather to boiler pressure which is what is pushing the system.

I have a similar system. Van Broklin used a cylinder with 2 different cyl. bores and a stepped piston. Steam fed to the bottom of the large piston and the oil was on top of the small piston. He then fed this output to the steam chest with needle valves to adjust flow.

I added sight glasses to this so I get a visual indication of flow. Works great, you always know that you are feeding oil and how often.
Fred V
Pensacola, Fl.
JohnR
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Re: Mechanical vs. Displacement/hydrostatic lubricators

Post by JohnR »

I am a little late to the game but I have interest in design information for a hydrostatic lubricator for my Locomotive (Sweet William).
What I am looking for would incorporate separate sight glasses with glycerin or salt water to monitor the oil consumption.
If anyone has information, pictures , or designs it would be greatly appreciated.
Need this to finish and get the engine on track this spring.
Thank you.
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Fred_V
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Re: Mechanical vs. Displacement/hydrostatic lubricators

Post by Fred_V »

I have CAD drawings for the sight glasses and what I call a Pressure Lubricator. it is a 2 step piston with throttle steam going to the large piston and that pushes oil from the small piston to the sight glasses. Been working for 20 years.
Send me a PM and I'll forward the drawings.
You can see the piston part on the cab floor to the left of the boiler; sight glasses above.
Attachments
Iris cab.JPG
Fred V
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JohnHudak
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Re: Mechanical vs. Displacement/hydrostatic lubricators

Post by JohnHudak »

Didn't the Lucky 7 have displacement lubricators (two) on the backhead? I think I remember seeing prints for them in ME Magazine?
John
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