Where the operator controls the feed rate in a cutting circuit, as found in trenching chains, drills, grade trimming wheels or saws, he will typically try to adjust the rate to prevent stall. A problem with this solution is that when the cutting is easy, productivity is lost. The simple circuit shown in Figure 1 may be a better solution in which stalling is eliminated and optimum feed speed maintained.
Figure 1. Incorporating a counterbalance valve in a cutting circuit can eliminate stalling and improve productivity
Operating principle
A counterbalance valve is a direct-acting, pilot-assisted relief valve. Pilot assist at port 3 lowers the effective setting of the relief valve at a rate determined by the pilot ratio. Port 3 of the counterbalance senses the pressure at the cutting device or saw. Port 1 connects to the feed circuit and port 2 goes to tank.
When the pressure required to drive the saw starts to climb too high, the effective setting of the counterbalance is lowered. Feed force will be modulated by relieving the feed circuit to tank, thus preventing the cutting device from stalling.
Design notes
This circuit is all about pressure control as opposed to flow control. Pressure control allows large changes in flow with small changes in pressure. The determining factor in this circuit is the pressure at the cutting device. Do not get too caught up in numbers. There are at least three performance curves involved and trying to predict exactly what will happen is difficult, if not impossible.
In order to serve this purpose, the counterbalance valve has to have enough capacity to handle the flow of the feed circuit. The counterbalance valve will probably need a low pilot ratio and a high setting.
Axial piston pump series for next-gen hydraulic applications
Hydraulic systems & components
Moog has launched its new AXP Axial Piston Pump Series, a next-generation hydraulic solution engineered to deliver optimal performance, reliability and cost efficiency for industrial applications.
Read more...Tuning into what your system is telling you Hydrasales
Hydraulic systems & components
Hydraulic presses can run like clockwork, but often it’s the things you don’t see, or hear, that carry the most telling signs of irregular system health.
Read more...A guide to common hydraulic system contaminants CT Hydraulics (Nqoba)
Editor's Choice Hydraulic systems & components
Every engineer, machine designer and maintenance professional understands that the heart of any reliable hydraulic system is its fluid. But the moment that fluid is compromised, your system’s life expectancy and your peace of mind drop dramatically.
Read more...Making lines safer with smarter connection Hydrasales
Hydraulic systems & components
Imagine connecting multiple hydraulic lines or a combination of hydraulic, electrical and grease lines with one single, confident movement. That’s the everyday convenience operators get from Faster’s MultiFaster multi-coupling systems.
Read more...Hydraulic system upgrades to boost performance and save money CT Hydraulics (Nqoba)
Hydraulic systems & components
Those working with hydraulic or pneumatic systems know that keeping your machinery running at peak performance balances productivity and cost. As systems age, they often become less efficient, requiring more energy and more frequent repairs. The good news is that you don’t always need to invest in an entirely new machine to solve these problems.
Read more...Navigating ISO standards in hydraulic cylinder manufacturing
Hydraulic systems & components
For hydraulics professionals, understanding and leveraging ISO standards is a powerful way to ensure quality and gain a competitive edge. Here is a guide to the most critical ISO standards for hydraulic cylinder manufacturing, showing how to use them to your advantage.
Read more...Heavy impact, smart control Axiom Hydraulics
Editor's Choice Hydraulic systems & components
Every now and then a project lands on your desk that’s equal parts heavy machinery and fine control - a tantalising mix for any engineer. A client approached Axiom Hydraulics with a project exactly like this.
Read more...Hydraulic systems in heavy machinery
Hydraulic systems & components
In this article, we explore how hydraulic systems function, their role in powering heavy equipment, and why they are the preferred choice for industries requiring immense power and precision.
Read more...How manufacturers achieve zero-leakage demands in hydraulic cylinders
Hydraulic systems & components
Imagine a world where your hydraulic cylinders never leaked. The answer lies in a holistic approach that focuses on the fundamental components and their interactions, particularly the cylinder rod and its surrounding environment.
While every effort has been made to ensure the accuracy of the information contained herein, the publisher and its agents cannot be held responsible for any errors contained, or any loss incurred as a result. Articles published do not necessarily reflect the views of the publishers. The editor reserves the right to alter or cut copy. Articles submitted are deemed to have been cleared for publication. Advertisements and company contact details are published as provided by the advertiser. Technews Publishing (Pty) Ltd cannot be held responsible for the accuracy or veracity of supplied material.
printer friendly version