Building a fill station

[LarryD]

I need some ideas on converting this gravity feed day tank to a pumping tank for the tractor.

The original design filled the tank and floats shut the pump off when full. I can switch the hose around to draw from the tank (got to add a pick-up tube) and I have a 5/8 hose with fill nozzle to get the fuel in the tractor.

My big concern is the pump, since it was controlled with the relay and floats for start/stop, what is going to happen when I turn it on and its builds pressure before I start flow through the nozzle? My friend says, "just do it" but I'll probably use water if I do, the clean up will be WAY less troublesome.

My other option is to find a fill nozzle with a micro switch but so far that isn't producing any hits on the net. I could also find a pressure switch that would cut the pump off and tie that through the relay but without a foot valve on the pickup tube, I think the pump would just short cycle. Am I trying to make this pump do something it just isn't designed to do?

My other problem is finding a fuel filter that will fit under the pump cover. It has 8" of clear space but the fuel filter/water separators I see will need 10"+ of head space.

So help me build my own Rube Goldberg device and stay green by using as much of the original tank accessories as possible. The tank is 50gl and epoxy coated inside, so it's a good starting point.

 

[BobRip]

Larry is the electric motor on top centrifugal switch start motor. If so it puts out a pretty hefty spark on starting. Look inside while it is starting and you can see if it spark (arc). I don't know that this will be a problem, but please be careful.

 

[LarryD]

I'm not familiar with the term "centrifugal switch" but if you mean power switch on and the pump is running then yes.

I was surprised to find the motor is not class 1 div. 1 but this unit has been pumping diesel fuel for more than 20 years without any problem so I feel comfortable with its new purpose. It was a day tank for an old 700kw Mitsubishi generator.

So today was spent plugging various ports on the tank and cleaning the inside. I got all the parts to make a pick-up tube so tomorrow I'll plumb the pump and do a test run on the new arrangement. I still have reservations on the pressure build-up on the pump but I'll be using water and a GFCI plug. It may all come down to replacing the pump in the cut-sheet with the one with the pressure relief valve or a different pump altogether. My goal is to get this up and running for less than $200...$50 spent today so I'm good.

 

[George2615]

We have a similar setup at work for our building generator. The 50 gallon day tank looks just like Larry's 1st pic. Its a standard type day tank unit with automatic fill used for standby generators. The 50 gallon day tank is in the same room as the generator and gets its fuel from an outside 1000 gallon tank when needed. On ours we plumbed in a manual 3 port valve (1 inlet, 2 outlets) so it either feeds the day tank automatically via the float operated switch or with a flip of the manual 3 port fuel valve it can be used to fill our portable 35 gal. fuel caddy with a flexible fuel hose. Our motor is a sealed motor and we added spin on fuel filters to both the in and out lines.

 

[LarryD]

That's good information George.

Do you have any kind of control handle on the end of the flexible hose? If so, it sounds like there is not any problem with the pump developing pressure before you start to fill your portable tank. On the other hand, the pump model I have does not have the pressure relief valve and yours may be the "R" model. Any chance you could pull the cover off and look for that as depicted in the Oberdorfer cut-sheet I posted?

 

[George2615]

We use the on-off-auto switch and have ball valves since we also use it to feed another day tank for our building diesel fire pump. Our motor uses suction to pull fuel in from the outside tank then pushes it either in the day tank or to a valved setup on the wall. The day tank has a return line back to the 1K tank as well. The pump can be plumbed to pump from your day tank to your tractor. We use a flexible 3/4" clear hose with a quick coupler to fill the caddy tank. When I go in Monday I'll gather whatever info I can get off ours and let you know. I'll take my camera to get some pics as well. Should post back Monday afternoon. On a side note, we replaced our day tank about 6 years ago and told the company to haul away the old day tank. I didn't have a tractor or need for it then but wish I'd have taken it to use like you want to. And we don't have any control handle on the clear tube used to fill the fuel caddy. We just plug one end in the coupler, turn a couple valves and turn the pump switch to manual, when full we switch back to auto and return valves the way they were.

 

[JohninCT]

From the pump catalog page you provided.

"If the discharge line contains any throttling devices such as a shut-off valve,
a spray nozzle or other restrictive device, it is necessary to have a relief valve in the
system which returns the liquid to the suction side or to the tank."

You need to install a relief valve on the discharge. Don't run the pump with the discharge closed (fill nozzle off) even with water. You will either burst the hose, break the coupling, or break the pump.

 

[LarryD]

You need to install a relief valve on the discharge. Don't run the pump with the discharge closed (fill nozzle off) even with water. You will either burst the hose, break the coupling, or break the pump.

Well team, todays test run produced mixed results.

I installed a pick-up tube on the tank port and was trying to figure out how to plumb the pump to the tube. The clearence was no more than 2" up and over so it was going to be difficult to span this with any sort of flexible tubing. As I was looking at the motor, it indicated a red wire on a certain terminal for CCW rotation, but the red wire was on a different terminal. Swap the red and black and the pump rotates the other way allowing me to use the original flex hose.

Time to test, open the fuel nozzle and turn the pump on. Works very well until I close the nozzle. The pump built pressure until the motor couldn't turn anymore....

So now I'm going to install a pressure solenoid and wire it through the relay. Reading the literature leads me to think a 50psi solenoid will work nicely.

So now I need a solenoid and a filter/water separator. Grainger, can you hear me know?

 

[BobRip]

I'm not familiar with the term "centrifugal switch" but if you mean power switch on and the pump is running then yes.

To further and better explain: Most electric motors of this size and single phase have two windings. Both are powered at starting and one is powered once the motor reaches a certain speed. One is turned off by a switch which opens up at this speed. The switch is opened by the centrifugal forces of the rotor speed. There is usually a spark created when it opens.
I hope this explanation helps. You can usually see the spark if you look in the end of the motor during starting.

 

[George2615]

Larry,
Sorry for the delay, I was tied up at work all day Monday and never got the chance to get info on our setup. We also have an Oberdorfer pump model N993 without relief (N993 has bigger inlet/outlet ports than your pump). Ours runs a 3/4" line in from the larger 1000 gal. tank through a 110V solenoid before the pump. We valved after the pump so we can direct the flow either to the day tank or out to a teed pipe system. (See Pics) We run an 1 1/2" return line back out to our 1K tank. Non of this info really helps with what you want to do but I can tell you we fill our fuel caddy 35 gal tank by turning the direction valve, opening the ball valve on the wall, plug the flex hose into the quick coupler, place hose in caddy and turn pump switch to run. It only take a few minutes to fill the caddy. When full, we reverse the procedure and put the pump switch back to auto position. Yours should be fairly simple to hook up with 110V power wired to your switch, suction side of pump connected to tank, discharge side of pump plumbed through a filter and finally to your flex hose. Valves may be added as needed.

In your case you'd leave the pump switch in the off position until your have your fuel hose in place between the pump and tank you're filling, open any valves you may have in line then turn on the pump until full.

With out a relief on ours we only risk pump or motor damage if we forget to open the proper valves. That happened one time when someone else tried to fill the caddy and did not have the quick coupler fully inserted and turned on the pump to fill the fuel caddy. The result was the pump and hose did not burst or blow a seal but since the pump could not turn (deadheaded) the motor burned up and I got called in to replace it. Maybe some of my pics will help you get yours plumbed up.

Pic 4 shows the quick coupler (left of green valve) we use to fill the fuel caddy. Yellow valve allows us to pump fuel up and into next room to keep the diesel fire pump day tank full. Pic 5 shows the fuel direction valve that switches flow from day tank to piping on back wall.

As long as you have your hand on the switch to turn off the pump when your tractor or portable fuel tank is full I don't think you'll need a relief. We've been running this setup the past eighteen years and and its only cost us one motor so far.