bizzarra theory?

[TECNOMODEL]

Good morning to all,
I ask an opinion on a theory reported to me today by the incompetent octogenary to justify a design choice.
the intake and delivery ducts of a pump (in the same) must have sections that vary so that the fluid has speed variations within the pump.
This leads the pump to be quieter.I press that for me the oleodynamics is a relatively new field, but this theory contrasts with what I found on the texts that I am studying privately.

I therefore ask you an opinion on this. Is the umpteenth shot of an incompetent who thinks he's a designer?

 

[Matteo]

mah, a sense of well-foundedness may have it, but before unbalanced I should have some extra data available (fluid, prevalence, flow, pump topology, ...). take into account that I am a fem/cfd simulation expert and not of oleodynamics specifically (on the forum you will find more experienced users of me in the industry).

ps: "varian" in the sense that sent is different from return, or that vary compared to themselves?

 

[TECNOMODEL]

hydraulic oil, variable displaced blade pump, valid theory for all flow rates.
our range goes from 16 to 120 cc.

 

[TECNOMODEL]

my doubt is: having these section changes in the fluid motion does not create turbulence?
already we do not have a linear motion, go to create further turbulence does not seem correct.

my other hypothesis, having these restrictions the fluid fillets could be detached from the walls and create cavitation.

I repeat, however, for me the oleodynamics is relatively new. But I'm studying and I often find myself with texts that contrast with what I'm told in the company.

So the doubt is that those who speak in reality know little about it and want only to justify some choices to say little questionable.

 

[Matteo]

hello, I don't understand one thing: is the section variation along the conduit? or do you go the warrant section over the return section? what is the prevalence of the pump? What is the speed in the conduit? What are the variations in the section (as a percentage of the turnover)? This is intriguing me:

 

[TECNOMODEL]

the variation would be along the suction duct.
at the entrance and in the area where the oil enters the cartridge has a speed of 1.9 m/sec, already faster than suggested by the texts but little.

changes are still not quantified, it would even want to create rooms along the conduit.

we can not talk about prevalence for these pumps because they are for oil plants, they have a max pressure of 250 bar.

 

[Matteo]

the variation would be along the suction duct.
at the entrance and in the area where the oil enters the cartridge has a speed of 1.9 m/sec, already faster than suggested by the texts but little.

changes are still not quantified, it would even want to create rooms along the conduit.

we can not talk about prevalence for these pumps because they are for oil plants, they have a max pressure of 250 bar.

I am as confused as you are
something like that had happened to me in circuits for floor heating systems and served to separate dissolved gases, but in the end it opted for a specific element. I can't explain why you got the indications!

 

[numero1]

Good morning to all,
I ask an opinion on a theory reported to me today by the incompetent octogenary to justify a design choice.
the intake and delivery ducts of a pump (in the same) must have sections that vary so that the fluid has speed variations within the pump.
This leads the pump to be quieter.I press that for me the oleodynamics is a relatively new field, but this theory contrasts with what I found on the texts that I am studying privately.

I therefore ask you an opinion on this. Is the umpteenth shot of an incompetent who thinks he's a designer?

Well, I don't know whether it's true or not, but the legend (as such), I can confirm it.
I also had been told by the super mega designer with 3,000 years of experience that etc. etc.
then did not do it for convenience, because having a regular section is easier to:
- realisation
- make any calculations
- prevents possible (but not certain) turbulence problems
Ultimately, I was told, that it was only done if it was necessary to reach lower noise levels than normal.
and, of course, only after specific customer request.
I don't think I've ever seen him do in my "oleodynamic" period.
This is what I remember, and I throw it there... :
Hi.

 

[Er Presidente]

The concept should be more or less this.
Hydraulic compression-phase pumps (grips, pistons, blades etc. not screw) tend to compress the oil inside the pump at a pressure greater than that of the mandate line. They basically compress inside and then release the oil in the pulse conduit. This creates a "train" of pressure waves in the oil that circulates that is the source of noise (more than that of the pump itself because it propagates in the plant).
If a diaphragm is interposed on the pipe, a calibrated perforated disc, the oil is forced to increase the speed locally, and after the diaphragm the oil will have a constant velocity, more track than the pulse train. some kind of "trafil" to make the idea.
the hole must be small enough to create a substantial change in speed but not too small to trigger turbulence on the fluid vein.

in practice it is sufficient "pinzare" on the outside of the rubber tube of the mandata a metallic sleeve with the appropriate struzzatura.
I attach photos of a car tube where you see on the right branch inserted the choke.

p.s.: The old deaneries, they seem rincoglioniti but, often, they welcome.... : )

 

[Lettore espatriato]

helmholtz

 

[Er Presidente]

helmholtz

I can't say for sure that it's the same phenomenon but, personally, I'm convinced that in practice an artificial resonance chamber is being created and that everything can be traced back to that theory.

 

[TECNOMODEL]

The concept should be more or less this.
Hydraulic compression-phase pumps (grips, pistons, blades etc. not screw) tend to compress the oil inside the pump at a pressure greater than that of the mandate line. They basically compress inside and then release the oil in the pulse conduit. This creates a "train" of pressure waves in the oil that circulates that is the source of noise (more than that of the pump itself because it propagates in the plant).
If a diaphragm is interposed on the pipe, a calibrated perforated disc, the oil is forced to increase the speed locally, and after the diaphragm the oil will have a constant velocity, more track than the pulse train. some kind of "trafil" to make the idea.
the hole must be small enough to create a substantial change in speed but not too small to trigger turbulence on the fluid vein.

in practice it is sufficient "pinzare" on the outside of the rubber tube of the mandata a metallic sleeve with the appropriate struzzatura.
I attach photos of a car tube where you see on the right branch inserted the choke.

p.s.: The old deaneries, they seem rincoglioniti but, often, they welcome.... : )

Interesting thanks.
but what you bring is on the warrant line.
The dean, as you call it, wants to do the thing in the suction ducts. and does not do a stroking but an increase in section of the duct.

 

[Er Presidente]

Interesting thanks.
but what you bring is on the warrant line.
The dean, as you call it, wants to do the thing in the suction ducts. and does not do a stroking but an increase in section of the duct.

but do not aspire from the tank?

 

[TECNOMODEL]

Yeah, sure.

the variation of section wants to realize it inside the pump, in the ducts obtained in the fusion.

 

[Er Presidente]

Yeah, sure.

the variation of section wants to realize it inside the pump, in the ducts obtained in the fusion.

theoretically also the aspiration is subject to phenomena of pulsation because the pump aspires packets of oil with impulses, it is probable that using an aspiration stroking is considered too penalizing and instead an increase of section leads to the same result, linearization of the flow, without imposing excessive load losses.
I personally feel the least problematic aspiration because it often has bigger and less rigid and much shorter tubes, with the nearby tank I think it's easier not to have problems.
But I don't deny that a change of speed even in aspiration can have its advantages.