Concrete blocks

Troubleshooting Challenge: Pressure Poses Problem

Feb. 12, 2021
Try your luck with this month's reader challenge.

A company that makes concrete blocks has a carousel with 10 horizontal two-piece molds that are clamped together, one at a time, by a 3-in. bore, 15-in. stroke hydraulic cylinder. Concrete is then poured into the top gate to fill each mold. The clamp cylinder and mold are then moved to the next position on the carousel by a hydraulic motor. The circuit provided shows the transfer motor and only one of the 10 clamp cylinders.

No more than two mold clamp cylinders move at a time. One opens while the other closes. Once the mold that’s opening trips a position sensor, the motor turns the carousel. After a dwell time needed for the concrete to harden, that mold is opened and a block removed. The cycle then repeats unless someone trips a safety-light curtain.

A problem occurred when a freshly filled mold would open slightly, allowing concrete to leak from the bottom gap of the partially open mold. This happened when the carousel first started to rotate resulted in a rejected block because of the void created.

Any idea why the clamp cylinders didn’t always do their job?

Find the Solution

Think you know the answer to this month’s problem? Submit your solution via e-mail. Bob and his company have been involved in troubleshooting, training, and consulting internationally for 30 years. All correct answers submitted by Nov. 16, 2019 will be entered into a random drawing for a $50 gift card. The winner will be notified, and his or her name will be printed in a future issue. Only one gift card will be awarded to any participant within a calendar year.

Solution to Last Month’s Challenge:

Press Mold Moving When it Shouldn’t

The bottom mold that occasionally moved as if it was losing clamping force only happened when a large pneumatic cylinder nearby was shifted and the propeller press started to open at the same time. The large cylinder caused the system supply pressure to drop when both were moving. Technicians installed a large-volume chamber in the supply line close to the press, and it solved the problem.

About the Author

Robert Sheaf | President

Robert J. Sheaf Jr., is the founder and president of CFC Insustrial Training, formerly Certified Fluid Consultants, part of CFC-Solar Inc. CFC-Solar provides technical training, consulting, and field services to any industry using fluid power technology. 

Continue Reading

BOOK 2, CHAPTER 12: Fluid Motor Circuits

March 18, 2009
Table of Contents

Motor leakage variations

Oct. 18, 2006
affect low-speed performance

Sponsored Recommendations


May 15, 2024
Production equipment is expensive and needs to be protected against input abnormalities such as voltage, current, frequency, and phase to stay online and in operation for the ...

All-In-One DC-UPS Power Solutions

March 13, 2024
Introducing the All-In-One DC-UPS, a versatile solution combining multiple functionalities in a single device. Serving as a power supply, battery charger, battery care module,...

Motor Disconnect Switches

March 13, 2024
With experienced Product Engineers and Customer Service personnel, Altech provides solutions to your most pressing application challenges. All with one thought in mind - to ensure...

DC Power Solutions: Streamlined Power Supplies for Every Need

March 13, 2024
CBI All In One UPS Power Solutions combine the requirements for several applications in just one device which can be used as power supply unit, battery charger, battery care module...