1950s Broomwade piston compressor

I have a Broomwade FA70 piston air compressor, dating from around 1951, that I need in full working order. Unfortunately the unloader valve / lever mechanism is not working. I am looking for advice on the best approach to repairing or replacing this. Alternatively, I wonder if the compressor could be adapted in some way with a new unloader? With many thanks.

Is it the unloader valve (part in the head), or the actuator (seen in 2nd - 3rd pics) that is not working? I have never worked on that style actuator/unloader (very cool by the way) before, but my guess would be the actuator has some 0-rings in it that may need replacement, and I'd have to take unloader apart to figure out what is going on there.

"Cobbling Up" Something to Get it Working

HarryWF:

DalmatianGirl61 has asked the right question: is it the actuator or the unloader itself which is malfunctioning?

If it's the actuator, you could cobble together a mount for a solenoid and create an electrical control circuit which keeps the unloader in the "unload" position for a short fixed time delay after the motor is energized.

(Then, you can take your time figuring out what's wrong with the original actuator, with an eye toward reverting to the original.)

If the problem is in the unloader itself, this should probably be attacked directly by careful dismantling. Any parts you need will likely have to be custom-made. This is an open-ended task whose duration, expense, and likelihood of success are impossible to quantify.

The cold, hard fact is that if this compressor is truly mission-critical to you, it should be replaced with something for which maintenance parts are currently available. I like old machinery as much as anyone, but sometimes we must bow to economic realities!

John R.

Is the check valve functioning? Is the actuator spring loaded? I have replace a unloader that whas plumbed in to the discharge line and to the pressure switch
Square D 9013FHG42J59M1X Pressure Switch

Personally I would take it apart, clean and oil. Might just be build up from years of use.
I just recently acquired an old wade air compressor minus motor that had been left out. The compressor was just about stuck from water getting into 1 cyl. After a good disassembly, cleaning and fresh oil it runs like a champ with a 1/2 horse motor. Not only is it over built but quiet as a sewing machine.

The unloader on that machine is in fact oil pressure activated- the machine cannot pump air unless oil pressure is developed within the pump. It has a leather packing on the piston and this responds to oil pressure to allow the valve to close. Pressure is controlled by the Igranic pressure switch and they don't work so well if this is replaced with a modern one for some reason.
The pump was also made by BEN patents and seems to be a design Broomwade aquired. I have one marked with both names, about 1949-1950 vintage. Motor is a MASSIVE Higgs.
The valve is servicable by removing the cap in the cylinder head. Lots get pitted seats, also make sure the check valve is working properly otherwise the valve and seat will overheat. It's a dead simple mechanism.
Later models used an air unloader which allows continous run but has no provision for oil pressure monitoring.

Thanks so much for all the replies, really helpful.

I don’t know whether it is the actuator or unloader valve that is at fault, but I suspect that neither have been operational for a while. The compressor is working fine otherwise, but the lack of unloading is putting too much load on the motor. There is a separate pressure regulator connected to the vessel that works, and which I guess acts independently.

Can anyone explain how the actuator should function? Thanks!

As suggested, it sounds like the best way forward in the first instance is to dismantle and clean/oil the actuator and then the unloader, and replace any gaskets if need be.

The compressor does perform a critical job in that it provides the air to a sewage ejector system. It would be fairly easy to install a modern compressor instead, even as a temporary measure, but as it is a heritage site here, it would be nice to get the original equipment working, especially when it is so well made, and sounds lovely when it is running.

Harry

Greenwud, thank you so much for explaining that. I replied before I had seen your message. The compressor does indeed have the Igranic pressure switch. Do you have any drawings of this design of compressor? Massive thanks, Harry

Sounds like Greenwud knows this system the best. My WAG is that on startup the actuator would pull down. To test, I'm thinking disconnect the rod, start compressor and see if actuator moves, if it does, pull/push against it to see if it can hold position. To test unloader, rod still disconnected, push/pull on it to see if it moves freely and loads/unloads compressor.

I have no idea what an Igranic pressure switch is, and google info is scant. Could one of you provide more info/pics? Or is this just a term for a standard compressor pressure switch that I have never heard?

If oil pressure is what closes unloader valve, and problem is hard starting because unloader valve is not unloading, my guess is that unloader is stuck in closed position.

Dalmatiangirl61, it's a pressure regulator made by the Igranic Electric Company.



Below is a detail of the top of the unloader valve. The uploader is definitely closed at the moment. I guess it is supposed to be spring-loaded to press upwards against the arm, so that it raises when the arm raises?



I am wondering if the plunger-actuator can be adjusted manually to set the oil pressure at which it moves? I am not actually sure where the check valve is on the compressor.

harrywf said:

Dalmatiangirl61, it's a pressure regulator made by the Igranic Electric Company.

View attachment 227774View attachment 227775

Below is a detail of the top of the unloader valve. The uploader is definitely closed at the moment. I guess it is supposed to be spring-loaded to press upwards against the arm, so that it raises when the arm raises?

View attachment 227776

I am wondering if the plunger-actuator can be adjusted manually to set the oil pressure at which it moves? I am not actually sure where the check valve is on the compressor.

Click to expand...

Not sure on exactly how the oil pressure is set, but I beleive it relates to the plugs etc on the end on the pump adjacent to the brass cylinder that control it and the system pressure. Basically, the mechanism ensures the pump is not loaded unless it has oil presure and motor does not start under load.

How it works...
If you unscrew the top of the brass cylinder and remove the plunger; mind the leather packing
Turning the flywheel by hand should fill the cylinder with oil and from here it's not hard to imagine that this oil forces the plunger and linkage up and allows the valve within the head to seat fully, allowing the pump to compress air.
IIRC there is a spring behind the valve to ensure it opens when oil pressure drops. Overheating and rust has the usual undesirable results on the spring and valve components and starting becomes "under load".

The oil pressure in mine drops fast enough that the motor does not start under load but this feature is dependant on the amount of air used- under heavy demand it would need to drop at a higher rate to ensure the function is maintained. The later air unloaders automatically solve this but lose the fail-safe operation.
Check valve on mine is on the inlet to the tank. It's a bronze flap valve.

Igranic made industrial switchgear from fairly early on in the century and their stuff seems well designed and massively overbuilt- lots of phenolic mouldings, neat cadmium plated mechanisms, silver contacts and BA screws. They were good enough for DSG and were bought out by Brookhirst in the mid 1950's.
The pressure switch on my compressor is fully rebuildable and incorporates a hysteresis setting that is maintained irrespective of the set pressure. It's different from the one in the photo.

Big slow turning compressors are a wonderful thing.....

If the compressor works fine otherwise, A modern pressure switch/unloader could be installed on the compressor discharge piping to allow for proper unloading of compressor with each off cycle and even allow owner to retain the present non-working setup if so desired.

Quality Air Compressor Pressure Switch Control Valve 145-175 PSI w/ Unloader 6856562389 | eBay

JL Sargent said:

If the compressor works fine otherwise, A modern pressure switch/unloader could be installed on the compressor discharge piping to allow for proper unloading of compressor with each off cycle and even allow owner to retain the present non-working setup if so desired.

Quality Air Compressor Pressure Switch Control Valve 145-175 PSI w/ Unloader 6856562389 | eBay

Click to expand...

It would require an air cylinder to hold the hold the valve open- essentially as was used on later models such as the AC41.

The oil pressure actuator and the unloader valve are now working, and whole system has been running well. Thanks so much to all the posters above and to Hermetic via here.

I took the oil plunger mechanism apart and cleaned it, and it seemed to be in good condition. By trial and error I got the oil flowing into it again. The top pin on the unloader valve was rusty, but once that was cleaned, the valve worked. One mystery is that the vertical rod assembly between the actuator and the unloader seemed to be about an inch too long. In the end I had to reduce its length to get it to work.

I would like to adjust the Igranic pressure switch, but don't know how to do this.

I had a similar situation with an older Kellogg compressor. In this case the unloader was not oil pressure activated, but rather activated by a set of fly weights on the end of the crankshaft. Parts were no longer available and there weren't enough of the originals left to determine the dimensions to fabricate a new one.

I left all the air and oil lies intact, but removed the what was left of the weights and mounting hardware. The compressor looks and runs like it originally did. I used a "Load Genie" unloader/check valve at the tank to perform the unloader task.


Load Genies & Unloader Valves

These valves are available from a number of vendors. If I recall the proper size for my compressor cost about $50.00

Hi First time on P.M. with some questions on a Broomwade Compressor
I have an N2 Broomwade Comp and guess its about 1940 to 1945 era. Single cylinder, 3 1/2" bore 710 RPM The one posted here has oil pressure decompression the one I have has a manual lever
I am restoring this unit and would like to know if anyone has technical data specification information and or parts information. Most of the main items can be salvaged but there is a need for reed valve washers and some other small items before I start to re-assemble
The unit has been underwater at some point during its life so there is a good amount of contamination
Cheers

Broomwade N2 type Compressor

Hi This is my first time on P.C. site so your help would be appreciated. I have an approx year 1945/48 Broomwade Comp. Type N2 Single cylinder 3 1/2" bore RPM 710 that Im restoring. Very similar to the one shown on this site but without the oil pressure unloader device
I would like to get information on where to obtain service/parts manual for the N2 unit. Specifically the head and reed valves as the reed flexible washers need replacing
The unit is in poor but repairable condition, with some TLC and a few parts it will pumping again
Thanks for taking time to read this request
Pak Pilips

Broomwade N2 type Compressor

Hi This is my first time on P.C. site so your help would be appreciated. I have an approx year 1945/48 Broomwade Comp. Type N2 Single cylinder 3 1/2" bore RPM 710 that Im restoring. Very similar to the one shown on this site but without the oil pressure unloader device
I would like to get information on where to obtain service/parts manual for the N2 unit. Specifically the head and reed valves as the reed flexible washers need replacing
The unit is in poor but repairable condition, with some TLC and a few parts it will pumping again
Thanks for taking time to read this request
Pak Pilips