FluidPower.Pro

Tag Archive: valve

Parker 689B series valve obsoleted

Parker 689B series valve

Parker 689B series valve

So, Parker continues to discontinue nice products 🙂

Now they obsoleted valves 689B series…

It is hard to find panel-mounted hydraulic push button valves. Most of the push-button valves are cartridges and to be assembled with a body. Body has mounting holes and some design of brackets is required to mount to assy body + cartridge to the panel.

The benefit of the valve 689B series was in mounting holes at the top, which lets easy mount to the panel.

In most applications, I easily replaced this type with an electrical button that operates a simple solenoids valve. But some specific applications require simple hydraulic manual control (some equipment at the rig, where the electrical-over-hydraulic control is not allowed by safety reasons.)

So, the question to you guys, can you advise an elegant replacement for this valve?

Updates:

Jan 29, 2020 By the advice of couple vendors I ‘m going to try to use Doering push-button valve as a replacement:

Doering push button valve

Doering push-button valve

Different spacers can be used, but I’m going to proceed with custom spacers to make button hight as low as possible over the panel. Not really elegant solution but time is limited and I need to make a decision. I will update this pose as soon as the panel is done to show how the solution looks like.

SUN Hydraulics – delivery time issue

SUN delivery issueWorking on the design of new projects I like to involve SUN Hydraulics valves and use them a lot. They are not expensive, pretty reliable and have uncredible understandable paper and online catalogs.

All these major benefits coming to naught as soon delivery time even of very wonderfull products makes impossible to use them in projects. This is exactly what going on these days.

Today I got a quotation from a local vendor for the valve FDEA-LAN with delivery time 31 weeks!!! It is longer than my project needs to be completed!

Helios Technologies (formerly known as Sun Hydraulics) has three facilities in the Americas, two in Europe and already three in Asia-Pacific (one more plant in China has been opened this year). But this fact doesn’t help to provide SUN valves faster.

Because the company, where I’m working now, has fillies in Europe we know the issue with the SUN product delivery time is currently common for the whole world. There no any comments from SUN and its parent Helios at their websites and I see the delivery time is increasing every month.

Therefore, I’m seriously starting to think about solutions on how to proceed. Problem is a lot of manifolds that have already been designed in our projects use SUN cavities. And to re-design of these manifolds is a pain, you know why. I’m seriously thinking to use SUN clones to cover these positions. Currently, I dug the next manufacturers:

  • Winner Hydraulic. This is a manufacturer from Taiwan, but they do not have distributors in North America.
  • PressureBoss Hydraulics Inc. From their website is not clear what country their plant is physically situated. They have distributors in the US but not in Canada.

For new projects, I’m starting to look at Parker and Eaton cartridges. They have a pretty good assortment and actually last months I already used some of their valves as quick replacement options.

How you are dealing with SUN Hydraulic delivery issue?

Proportional valve control calculation. Part 2.

Part 2. Proportional control in the regeneration mode.

Regen mode - proportional control

Fig.1. Regeneration mode schematic

See also:
Part 1. Proportional control of double acting hydraulic cylinder.
Online calculator for cylinder proportional control.

The goal of the calculation is definition of a cylinder velocity at the current operating voltage at the valve’s solenoid.
For calculations we need to know: cylinder and valve parameters (take them from manufacturer catalog), values of forces at cylinder rod (load) and pressure drop at return line (can be assumed as zero if unknown).

Summary:
2.1. Regeneration mode schematic
2.2. Regeneration Mode: Cylinder extension calculation
2.2.1. Balance of forces at the cylinder
2.2.2. Spool lands ratio and pressure drops at the spool lands
2.2.3. Hydraulic cylinder extension. System pressure calculation
2.2.4. Flow through spool lands: max. and at current voltage
2.3. Hydraulic cylinder retraction calculation
2.4. Final words….

Valve’s middle position configurations

Here are the practical advises to select the configuration of the middle position of 4-ways 3 positions directional valves. There are more than 250 configurations of the flow ways usually used in the practice, but in this quick review let see the generic configurations only.

~~~ // ~~~

All ports are separated from each other:

mid_pos_01

Configuration notes:

  • This spool configuration is used where two or more operations are performed by a single pump or an accumulator. Pump output is available for other valves and actuators with this center condition.
  • Closed port P prevents the loss of fluid from the pump or accumulator when the spool crosses center. Avoid fixed displacement pumps for this configuration. More info about close circuits you can find here.
  • The spool-type valves are not zero-leaking devices. In actual use, leakage oil across the spool lands pressurizes A and B ports, possibly causing a single rod cylinder to extend trough piston/annular area difference. By the same reason this configuration is not for holding applications.