I'm surprised neither your oil supplier nor your pump supplier had the answer here. It's a fairly well known process called mechanodegradation. The high shear rate that the hydraulic system imposes on the oil causes some of the heaviest [largest/longest chain] hydrocarbon molecules to be...
Not being able to break into the manifold makes it tricky. Can you send a circuit? Here's a few suggestions anyway, hopefully one of them has some potential.
If the actuator always works at the same sort of pressure (when running properly) then you could consider teeing a small, rapid response...
On systems with multiple LS signals where several actuators have to operate simultaneously it is common practice to install pressure compensated flow control valves for each service. The actuator which is working at the highest pressure “calls the tune” and dictates what the pump pressure will...
Hi there Hydroman247
If your rotary actuator is receiving its flow from a simple throttle valve then the only reason you are over-speeding sometimes is because there is too much pressure drop across the valve, i.e., you are getting too much flow. Your load sensing system is supposed to be...
Sorry, I was away for the weekend and didn't pick up on your request for details of the pump I suggested - anyway, you seem to have found a suitable candidate.
With a centrifugal pump you will have maximum flow rate at minimum head (outlet pressure) and zero flow rate at maximum head (the point...
Decades ago I worked on a project which entailed close liaison with a well renowned firm of consulting civil engineers. One of the consultants sort of took me under his wing and gave me an excellent piece of advice: Any fool can build a bridge which stays up, but it takes an expert to build a...
The Davey pump looks like a good enough choice to me. So what if the guy was reading the datasheet out to you - would you prefer him to have memorised it, or made up the numbers?
A petrol pump is going to be a bit of a pain to start and stop automatically (you will need a float switch and an...
I only mentioned the ROV application as an example where the physical effect of a general increase in absolute pressure causes a general increase of bulk fluid viscosity.
Jesahe's original question was all about the Fanning equation indicating that the absolute pressure was not a consideration...
Mineral oils certainly do exhibit a significant change of viscosity with pressure.
The Barus equation gives this relationship as:
VP = Vatm * e^(alpha * P)
Where “Vp” is the absolute viscosity at the new pressure, “Vatm” is the absolute viscosity at atmospheric pressure, “P” is the new...
I can see why you would want a pressure compensated flow control valve now – presumably you want the speed to remain constant regardless of the force needed to push the sample. You might, however, be disappointed with the performance of the simple pressure compensated flow control valves which...
Hi Mike
The thing looks like a press of some sort. It is possible that using the existing relief valve as a bypass flow control will prevent the cylinder from acheiving the full application force.
DOL
There are a lot of systems that do use accumulators as a suspension spring (fork lift trucks being a common example). It is also common to switch an accumulator into circuit on the lift circuits of off road boom lift vehicles.
The business of the gas heating up when it is compressed (during...
Well there's the answer!
Your pump flow rate is 60 cubic inches per minute - that's less than 0.26 USGPM. Your flow control valve is actually a 3/8" NPTF pressure compensated flow control valve with reverse flow check and a quick check of the valve's datasheet shows that the MINIMUM setting of...
I’m surprised that you are limiting your deliberations to such a narrow temperature band. You haven’t said where in the world you will be running this vehicle so let’s guess at somewhere in the temperate zones of the northern hemisphere. It is easy to imagine that, after running at high speed...
The conversion might just about be possible if you are very circumspect with your choice of components.
You should be able to get a suitable motor for about $130 but this will be a budget Taiwanese copy of the real thing. At this end of the market there isn't much difference in the price of...
To be honest, you should attach a circuit diagram so that we can see more of the picture, but here's a simplistic explanation based on the presumption of a very simple circuit.
I guess there is some sort of relief valve in the system which opens at a particular pressure and spills some of the...
Very first question: 16 GPM? is that US gallons per minute or Imperial gallons per minute.
Do you want to use the full 16 GPM and let the pressure go up and down according to the load on the motor? or do you need to make sure that you don't use the full 16 GPM so that the pump outlet pressure...
Hi sam5586
Some systems vibrate [until fixed] and others don't need fixing. If you only have experience of systems that didn't need fixing then, unfortunately, you have nothing to draw upon. A few quick answers from an engineering tips forum cannot take the place of the professional fluid...
The usual rule of thumb for "hydraulic" reservoirs is that the tank should be three times the flow rate per minute. So a 240 L/min flow rate would indicate a 720 litre tank. Then add 10% for the air space above the oil and that makes it 800 Litres.
The reasoning behind this rule of thumb is...
