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Dean Smith Grace 1709, apron Bijur lubricant meter valve check.

imported_brian_m

Cast Iron
Joined
Jun 25, 2006
Location
Oregon
I can usually work things out but this problem is beyond my experience.

I have just replaced the four Bijur metering valves on the apron lubrication of my 1709, Bijur type FJB 0 meters. I have confirmed adequate lubricant flow as far as the manifold where the four metering units are mounted but I can't seem to get any flow beyond the valves when they are in position. All of the 5/32 copper lubrication lines have been replaced and confirmed as clean and free flowing. The meters are installed the right way around. The lubricant pump is properly primed and flow is visible through the provided view port.

If I remove a metering valve from the manifold lubricant flows freely from the distribution block. If I replace all the metering valve there is no apparent flow from the open end of the attached copper tubes on any of the distribution lines. If I replace a metering valve with one that has had the internals removed I see flow from its line. So, this does not leave many options.

a) Could it be that the flow is much lower than I expected and it is so low it is not visible (although I have pumped the oil by cranking the carriage for a considerable time).

b) Although there is flow for an open line the pump output pressure is too low to force oil through the metering valves.

Does anyone know just how much lubricant I should see from a metering valve? Is correct flow obvious for the type 0 valve? Can we express it in drips per minute for example?

Thanks, Brian
 
With those meters you should see drips with enough cycles of the pump unless perhaps your pump isn’t delivering the necessary pressure (psi).

I recall seeing a table somewhere that showed quantified volume per cycle but I’m not sure where. This has relative volumes across the meter unit types.


This one has more detail but says there is no specific flow rate, just relative in the system design:

 
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Thanks Bb,

I am beginning to suspect low pump pressure since I can get flow with no restriction but none through the metering valves. I'm working on it.
The manual I have does not detail the design of this pump and its other parts such as the control valves and they do not seem to make much sense, I am wondering if there is a spring missing on the pressure relief valve.

Brian
 
Those Bijur pumps do get clogged up and don't pump oil very well. You need to take the pump apart, clean and replace the filter screen if you can't see thru it. Also, flush out all the oil lines with fresh oil. I assume you are using way lube and not gear lube to pump thru the pump and metering units?. Do all of this and report back.
 
Those Bijur meter units are only meant to pass a drop at a time, and it can take seemingly FOREVER to see oil at the end of the tube. IIRC, size 0 is the next to the lowest flow rate, so double forever. First break the lines at the inlet side of the meters to ensure you have oil at the meter units. Then, take the lines off the output side... and pump eight or ten times. you should see oil coming out of the meter units. If not, one of two things: the meters are plugged (you did say they were new, but are you sure?) These things are next to impossible to clean. If the meter units are new, I would expect a bad pump. The system I maintained pumped 30 PSI (it had a gauge.) The pump should hold pressure for a while, if not, it is likely worn out.

Dennis
 
I've seen the metering units all the way down to 5/0 being used! I have a couple of 3/0 in my stuff. I like them flowing as much oil as needed without making too much of a mess. Usually a 0 or 00 is as small as I will use on the stuff I play with.
 
Thanks for the input gentlemen. I am understanding a little more about the metering valves.

To clarify, although DSG used Bijur metering valves they built their own oil supply system. Lubrication for the ways is by oil from the apron sump (which means you need to keep this oil topped up). The oil is pumped by a cam on the shaft of what I was taught to call the long-feed handle. The actual pump is a bronze piston mounted horizontally in a housing on the front of the apron which is held against the cam by a return spring. I have fitted a new O-ring seal on the piston. Therefore, the pump operates manually when you turn the long-feed crank handle or automatically in the power feed modes. Above the pump is a ball-bearing check valve as you would expect. Alongside this check valve is another ball-bearing valve which I think must be a pressure or flow control valve but I can't see how this works. I expected it to have a spring fitted but this is not the case. The lube is fed through a filter before being supplied to the system.

There is a sight glass fitted to allow viewing the spurts of oil flow. Just how this part of the system works I can't understand either. The spurts of oil go into a large cavity so unless this cavity is pressurised how does the oil get into the following pressurised part of the system? Perhaps the spurts of oil visible are only a part of the pump output which is no longer pressurised and is used for general bearing lubrication.

Not having the pump operation illustrated in my parts manual is a real pain.

State of the tests so far. Oil is getting to the distribution manifold mounted on a side face of the saddle at good flow rates. I have one drilled out metering valve fitted at one of the positions on the distribution manifold and this provides the same high flow at the end of its attached copper tube. If I fit a new metering valve at this position I see no flow at this open tube or the other open tube that is also disconnected from its final destination.

Thanks, work continues.
 
It's been many years since I've had a Bijur oil pump apart. But yes, it has two ball type checks in the pump. One is spring loaded, and I can't remember about the other one. I don't recall having any kind of service instructions on the pump. I'm pretty certain the pump that DG&G used is a Bijur pump. They are obsolete and not made any more but do show up once in a while on eBay for sale. It sounds to me that you have some clogged metering units still. You need to buy new ones to replace the old ones with. The old metering units are hit and miss on getting them to flow oil thru again. Also, you haven't indicated that you have pressurized oil flow thru the pump. Like others said about 15-30 psi is needed to get flow thru the metering units. As for the drip window on the apron, never heard of one used. If there is such a thing in place, it probably had a 00 or 000 metering unit dripping oil into the window for an indication of oil flow would be my guess.
 
Good guess 4GSR.
The drip through the sight glass is probably the lube for the apron gears that then drips back into the sump. It would make sense to feed the gears through a higher flow supply.
 
Sorry to keep belabouring this subject but I am hoping that something I mention may light a light bulb in someone's head.
Latest test.

I connected one port of the lube distribution manifold directly to a pressure vessel containing lube oil. The first test was to pressurise the vessel to 30 psi. There was no flow from an open copper tube connected to one of the other manifold ports through a metering valve. I increased the pressure to 45 psi, still no flow.

The data plate on the lathe recommends Shell Tonna 33 which is no longer available. I know I can get a substitute for this oil but since I am purging the lube system on the lathe I am using 30 weight non-detergent as a temporary substitute. Could this viscosity be causing a problem?

The metering valves are new supplied from E-bay sourced in Taiwan, the seller has 340 positive results in the last year with one negative so they seem to be OK.

Brian
 
Actually Thermite you can cool down. The items I purchased were sold as Bijur B2495 in the advertisement so I thought I was actually buying genuine Bijur parts. It is not unusual that brand name parts are sold through dealers or as surplus and I did not know that these parts were made in Taiwan until I received the package. It is quite likely that the Bijur products are made in Taiwan and I generally find Taiwanese quality very good.

I will check with the seller and see whether their advertising is inappropriate although, as I mention, they seem to have an excellent E-bay reputation.
 
Just pressurizing won't do, the meter units need to see a pulse of pressure. These systems are designed to be able to have the oiling points arranged along a single line... I know the average mill or lathe has one manifold with a half dozen meter units lined up, feeding to different points, but that's not really what the Bijur system is designed to do. I maintained an injection molding press for years that had, IIRC, 55 meter units, on one circuit. A sub-circuit would tee off, jump via flexible tube to one of the toggle pins, and feed the five link bearings IN A SERIES arrangement. If the meter units fed oil continuously, all the oil would run out of the first dozen or so points, and the distant points would get none, which is exactly what happened when a tube broke. Luckily, the flexible tubes were clear plastic, so inactive lines would eventually get air bubbles, which would start slowly progressing when the problem was fixed. The pump was on the press hydraulic system, one stroke per press cycle, and had a cap that allowed access to the piston to pump by hand. 20 or 30 strokes would only move those bubbles 2 to 3 inches. Dealing with a leak took a LOT of hand pumping to get things right. I finally added a tee and a meter unit to drip in the open at the far end of the system as a visible check on system integrity; when it stopped dripping I knew there was a leak someplace upstream.

Dennis
 
This might have revealed the problem. The proper Bijur valves are apparently designed to open at 5 psi pressure. When you dig in you find the detailed specs. on the ones I received give an operating range of 20 to 280 psi. It looks as though my little apron mechanical pump could not give the required pressure. I am returning the valves and meanwhile I will get the proper Bijur part.

Incidentally the reason I did not buy from Bijur initially is that the wanted me to "Please sign in for a quote". I do not see why if I am sitting there with a credit card in my hand I have to provide them any more information. Tell me what you want and I will give you my card number.

.
 
Rig you up a short length of 5/32" tubing to the end of an air nozzle and attach one of the metering units. Give it some air and you should feel air come out of the other end of the metering unit. If you don't, something is wrong with the metering unit. this is how I used to test them.
 
Thank you all, this has been a learning experience. Metering valves seemed to be such a simple thing.

I have genuine Bijur parts on order. I am upset with the original supplier although I should have been more careful. The heading of the ad. was deceiving, they named the parts as Bijur and even gave the correct Bijur part number, it was only when you scroll down that you find the tech. description says the parts could be from various suppliers. My fault, be careful out there. It may not be wise to publish the company name, I will simply say they are based in CA and seem to sell an extensive range of parts with, apparently, high satisfaction. Whether these parts would have worked correctly in a more modern lube system rather than my mechanical "one shot per turn of the crank" system I can't say.

In any case, many thanks for your input, I will report success.
Brian
 








 
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