Gast Iron Pump Vs. Aluminium Pump 2

[5000CT]

Hello Guys/Girls

I am looking for ideally a cast iron pump SAE B mounting flange 13T 16/32 shaft and 32cc. However I am having difficulty finding this type of pump. I can however find rather easily a Aluminium pump. Which is a Bosch/Rexroth PGH4-2X series pump. However they do not have the shaft spec that I need. Reason I am limited on the shaft type is because it is being coupled into a engine aux PTO drive. Please see the attached image of the engine I already have a cast iron tandem gear pump (Bondioli & Pavesi) in the model. I am going to be using the PTO drive C as shown on the bell housing end. (mounting a pump on the fly wheel is not an option as it is used to drive another function)

Now basically I would like a pros and cons of aluminium pumps Vs. Cast Iron pumps if possible?

Regards

 

[5000CT]

other attachment!

 

[hydromech]

My understanding is that cast iron is used where the operating pressure is higher.

For example, external gear pumps. Group 1 and 2 gear pump can just about reach 300 BAR, but cyclic loading allows the seals to be extruded up the side walls. I don't know of any aluminium group 3 external gear pumps that can do 300 BAR.

Come to think of it, I don't remember ever seeing an aluminium internal gear pump. What makes you say that the Bosch Rexroth pump is not cast iron? I've looked at the data sheets you posted, but I can't see where it says the body is aluminium???

This may relate to why you can't get the flange and shaft you want in cast iron, the torque rating perhaps???

Adrian

 

[5000CT]

Adrian

Thanks for the reply

Maximum torque that can be transmitted is 64.5 N/m which is well within the torque limits for a 13T 16/32 DP shaft. I'm struggling to find a group 3 cast iron 32/33cc pump with the flange and shaft spec that I need. Finding a group 2 aluminium one is not a problem. Given the running pressure we need is only 116bar for this pump do you think we would run into any problems with an aluminium group 2. The application if off road machinery. This will also be subject to constant loading and unloading.

Regards

 

[micalbrch]

Parker (

http://www.parker.com)

manufactures gear pumps with a cast iron body. But I'm surprised to read (as Adrian) that the Bosch/Rexroth serial shall have aluminum housings for that high pressure.

 

[hydromech]

I am still not convinced that the Bosch Rexroth pumps are actually aluminium.

It does not confirm in the literature, but the pictures look like cast iron.

I am not sure Parker make internal gear pumps...

Try Bucher, they make very good pumps, I used them on US Naval systems...these are cast iron pumps with ISO 3019/1 and /2 flanges.

http://www.bucherhydraulics.com/311...ducts/Pumps/Internal-gear-pumps-QX/index.aspx

At 116 BAR, either iron or aluminium will be good. You would have to talk to Bosch Rexroth about the random vibration amplitude capacity. No problem when static, 20G acceleration makes a big difference.

Adrian

 

[5000CT]

guys very sorry i attached the cast iron pump that does not have the correct shaft spec that we would need please see the attached documentation on the aluminium pump. Lead designer (Boss) is afraid of attachinng a aluminium pump form previous bad experiences.

Personally at the preffure we will be working it at i dont think there would be any noticable difference.

P.s the Butcher pumps are looking promising even for the tandem pump. As we are trying to find a tandem pump with either a rear inlet, with 2 pressureised ports on the side. Or 1 suction on side 1 pressurised on the same side and one pressurised port on the rear face. It too must have SAE B mount with a 13T 16/32 DP shaft.

Thanks for the help either way guys!

 

[hydromech]

Now that looks more like an aluminium pump!!!

I don't blame your boss. Having worked in fluid power for 20 years and now being a project leader in design and development of pumps for heavy duty diesel engines, I wouldn't want to attach an aluminium hydraulic pump to a PTO either.

Glad to help.

Regards

Adrian

 

[hydtools]

You can find pumps with cast iron mounting flange and aluminum gear housing.

Ted