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Date/Time:  1/11/22 3:17 GMT

AAK Unique Design Eliminated the Scream of Hydraulic Relief Valve

When I opened the mailbox this morning, I saw a reorder for 500 pilot hydraulic
relief valves from Jimmy. He mentioned that the pilot hydraulic relief valve
designed by AAK had been used for 2 years and without any complaints. Jimmy is
a purchaser of American company Vickers, responsible for the purchasing of
hydraulic parts. 2 years ago, his company encountered a complaint from customer
for a hydraulic pump. The customer complained that it screamed after being used
for a period of time. After dissecting, their engineer found that there was a
problem with the hydraulic relief valve in the hydraulic pump. The boss asked
Jimmy to solve the problem as soon as possible. Jimmy sent the hydraulic relief
valve back to the original supplier, but the supplier replied that the
inspection result was good. Maybe the problem happened during installation.
Jimmy’s engineers tested the samples by themselves and found that there was no
problem with the hydraulic relief valve, but there was also no problem with the
installation method and operation. Now Jimmy is depressed. The boss is pushing
for status, but he has no clue.

He contacted with several local hydraulic valve manufacturers in the United
States, and they all replied that there was no problem on the hydraulic relief
valve. One day, after browsing AAK website ( in Google,
Jimmy sent an email asking if AAK could help analyze the reason. We replied
that it would be better for engineers to have video communication on site

Jimmy decided to ask Vickers engineers to make a video with AAK engineers the
next morning. After more than half an hour of observation, AAK engineers found
that once the pressure oil at the inlet, outlet and control port of the
hydraulic relief valve fluctuated, it would produce a scream. We got their
original samples and drawings, as well as the working parameters of the
hydraulic pump.

After 15 days, AAK sent a sample of the pilot hydraulic relief valve. A week
later, Jimmy e-mailed us that AAK hydraulic relief valve was installed and
tested on site for 24 hours, and there was no scream. Jimmy wondered why there
was no scream when AAK hydraulic relief valve was used.

AAK engineers analyze the cause from the hydraulic impact. After the hydraulic
pressure impacts the main valve spool in the hydraulic relief valve, the
pressure oil converges through the check valve, resulting in fluid impact and
fluctuation, causing the hydraulic relief valve to oscillate, resulting in the
instability of the pressure oil at the outlet of the hydraulic pump. Because
the pressure oil output by the pump itself has pulsation, the pressure oil
output by the pump will fluctuate strongly and arouse the vibration of the
hydraulic relief valve. For the natural frequencies of the two hydraulic relief
valves are the same, it causes the resonance of the relief valve and the scream
occurs. AAK engineers changed the design to replace the two hydraulic relief
valves with the same pilot hydraulic relief valves, and set the corresponding
overflow value according to the working conditions. The sample was made based
on this process idea.

After solving the problem that bothered Jimmy for half a year, he can finally
confidently report to his boss. After listening, his boss also praised AAK
hydraulic valves and hoped that AAK can produce 50 pilot hydraulic relief
valves as soon as possible to solve the complaints from users first. With AAK
unique designed pilot hydraulic relief valve, there has been no complaint about
scream for two years. Jimmy doesn't want to find a second supplier anymore.

AAK pilot hydraulic relief valve, the unique design of the remedy to the case,
welcome to have a small try! , l/hydraulic-relief-valves-aak129
AAK Unique Design Eliminated the Scream of Hydraulic Relief Valve
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