The chart of manifold’s ASSY components, provided below is not a rule or a standard, this is just what I usually use in my practice. I decided to share it because this info may be interesting for others.
At the latest my project I used hydraulic motor Rexroth A2FLM710 (710cc). The motor works at 1400 rpm and provides 590 HP to the consumer. For safe motor work, I always try to keep the case temperature below 80*C. The easiest way to do this is a flushing flow adjustment.
In addition to the flow, you need to keep your eyes on the motor case pressure and try balancing to prevent overpressure in the motor case (check in the motor manufacturer’s catalog the max available case pressure to make longer life of motor shaft seals).
The values I have gotten: 21 GPM at 30 psi case pressure and in the worst-case scenario (max motor load, warm hydraulic oil) max case temperature was around 80*C
There are no prescriptions or recommendations for valve or orifice size in motor catalogs for flushing flow, so the selection of flushing valves is a challenge.
Of course, you can find orifices (with different diameters) provided by the manufacturer with the motor in the motor’s catalog. But the flow and result case temperature will be different from application to application and the selection of the correct orifice is an engineering responsibility without any help or advice from the motor manufacturer.
Moreover, the manufacturer can’t provide all range of orifice diameters so the selection in the catalog is usually limited. And as you can see, sometimes values of flushing flow can be really huge and the only experience helps me to select the right flushing valve size at the beginning of the project.
I still believe, manufacturers can provide some diagrams/charts with correlation “power -> flushing flow” for approximate/preliminary estimation of the flushing valve size. Because I do not think everyone has a chance to make long tests during production and play with valves sizes…
What do you think?
Just impressed how efficient can be Magnetic Filter Scrubber. I use it at all applications and photos below can explain why.
I mount these filters at the bottom of the tank downstream the butterfly shuttle valves (tank outlet ports). In case of service, these valves closing and checking/cleaning of scrubbers can be done without full oil drain from the tank. For that, each scrubber is provided with -04 orb port which lets to drain small qty of the hydraulic oil from the scrubber itself.
I’m not showing the brand of the scrubbers at the photo, this is not an advertisement of the specific brand, just wanna share the idea to use scrubbers, especially in the mobile applications, where the size of tanks usually not big enough to sedimentation of particles to the bottom of the tank.
At this article, I show my vision on how to:
- determine the value of the heat needs to be rejected from the system;
- calculate and select the right cooler size.
…and will provide an example of cooler calculation and selection.
What is a cooler and what is a heat exchanger?
The hydraulic cooler is one of the heat exchangers type. But, what is a heat exchanger? The best definition of the heat exchanger is:
Heat exchanger is a device that transfers heat between two fluids.
The simple sentence but a very good description, because fluids can be either oil, air, water, etc., and because transferred heat can be for either cooling or heating target.
There are two most popular types of heat exchangers in hydraulic systems:
Plate heat exchangers
This type has the best value of efficiency/reliability and designed for both cooling and heating applications and a very good for low-viscosity fluids. Pairs of plates can be removed individually for maintenance, cleaning, or replacement. Another advantage of the plate is exchangers is their low initial cost, as well as easy and inexpensive operation.
Fan radiators (air-cooled)
This type is the only option where water is unavailable or expensive for a delivery. From benefits: low maintenance and operating costs and the only option for oil cooling in mobile applications.