Orifice flow calculation
Calculation flow trough orifice
Here is an online calculator of the flow through the orifice. Using this chart you can determine both flow through existing orifice or estimate the orifice diameter for required flow.
Manifold for motors in close loop.
Just a note about one direction motors (not reverse!) in close loop applications.
There are a lot of different ways how to proceed with a hyd. motor in close loop applications to make motor work safe and reliable. From my experience, almost each one direction motor application is required to have the next items:
- Anti-cavitation check valve
- Pressure relief valve
- Case flushing valve
- Test ports
Each motor manufacturer has own solutions for their motors, but here are problems you can meet:
- OEM solution usually is not flexible: you can use only what they have. If you need for example flushing of the motor case – you have to design something external anyways.
- Price for these options is unreasonably high;
- Delivery time increased on 2..6 weeks;
Here is how I like to proceed for one direction motors – with an external manifold, mounted by hoses flange botls directly to both motor ports:
- The manifold is designed with through “A” and “B” SAE Code 62 ports with grooves for O-Rings from both sides. Using gender changer plates (for example, solution from Inserta) the manifold can be mounted in any direction/position and ports can be easy swapped if it required.
- Anti-cavitation valve is integrated to pressure relief valve is a very compact cartridge, which saves space in the manifold. Like an example, here are solutions from Hydac (DBRV16P) and Rexroth (MHDBN).
- Flushing flow control valves examples: HYDAC (SR06-01 or SR08-01) or SUN Hydraulics FDCB-LAN. The benefit of Hydac SR valves is SAE ORB cavity: if you do not need flushing valve you can still use this universal manifold but jut plug cavity with the regular ORB port plug.
- And of course test ports. I like to involve as many test ports as it is possible to make easy maintenance.
The benefit of using flushing flow control valve (vs fixed orifice) is you can adjust required flow for any motor size specificly for application conditions, you do not need to pick the size and replace the orifice with each new motor.
The only thing you have to be careful about is a motor case drain pressure. Therefore, before adjusting a flow put a pressure gauge between the manifold and port “D1” and increase flow slowly to reach the required flow rate but not exceed max case pressure.
Flushing line from the manifold needs to be connected to the bottom case drain port of motor. From the top case drain port, the line needs to be plumbed directly to a tank.
Hydraulic cooler: suction or blowing air flow?
Just got an interesting response from Emmegi technical specialist about a choice between suction and blowing air flow of hydraulic coolers. The response is short but very deployed, so I would share it “as is”:
Here is our take on suction vs. blowing air flow:
- Blowing air flow: If you have seen a cooler that has been in the field for a while you will notice a clean doughnut shaped area where the air is blowing thru the cooler. In all four corners and in the center you will notice gunk/debris.
This indicates that the full surface area is not being utilized.
- Suction air flow: The fan creates a vacuum between the fan and cooling element. The air is very evenly distributed across the face of the cooler utilizing the full surface area.
On the downside, the fan blade is operating in less dense hot air, reducing the performance of the fan.
SUMMARY: For most hydraulic cooling applications the two effects cancel each other out and end up having nearly identical performance. The exception to this rule is for high temperature applications (oil temps above 175F).
- For high temp applications the reduction of air density makes the blowing design more efficient.
- The reason we supply standard coolers with suction air flow is that since the performance is typically the same, the suction air flow traps debris on the outside of the cooler where it is not only visible, but can be cleaned much easier.
if be honest, before this time I thought the suckers are more efficient coolers. Even to order cooler you need to specify symbol to make a blower (because the sucker is a standard).
Parker 50P filter will be discontinued soon
Just got a feedback from one of my Parker suppliers about 50P series filters: this series will be discontinued soon. I used them in a lot of my projects in the past and still continue to use them now. The supplier informed me about the next:
- These filters are a pretty old design, from middle 1960’s and this is why this is a time to stop using these filters.
- The suggested replacement for new projects (by pressure and flow rate) is WPF series
- The price for 50P filters will be increased soon to stimulate customers to start to use WPF.
- No more expedite option even with the price increasing for 50P filters.
The main problem with WPF filters is a design: Base-ported (50P) vs head-up (WPF):
In some applications where I use 50P filters now, will not be so easy to replace filters with new WPF series. There are a lot of factors like access to replace filter element in the current place, different mounting brackets will be required, extra hours for our mechanical engineers to design these brackets and etc.
Moreover, in the applications, we have already done for the years this replacement will not be possible at all.
This is why the best way if 100% replacement can be found.
Take a look at filter Schroeder KC50:
- Mounting dimensions are 100% the same (5″ x 4.5″):
- Schroeder KC50 is approx. 2.5″ higher
- The same rated pressure 3500 psi (240 bar)
- The same flow rating: up to 100 GPM
- BONUS: Filter elements are interchangeable!
You can check Parker’s filter elements for 50P series here and you will be surprised: they matched Schroeder’s KC50 series!
So, if you take a look closer on Parker 50P and Schroeder KC50 you can find these products are 99% identical and we can use Parker’s filter elements in Schroeder filters and opposite.
Really, these filters are suspiciously similar! Therefore I made a request to Schroeder about KC50 filters and got a confirmation they were designed to be interchangeable. The only thing they noticed to be aware is the 50P had an option where they have a reverse flow check option for hydrostats in the housing and the Schroeder version of that filter assy is a KFH50. Also, for 3000 psi pressure (210 bar) you can save a little bit money and use identical filter KF30 series (with the same flow rate).