Parachute valve

Pete

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Pete 02.07.2012 13:56 6 ↑ 0 ↓

Hi!

Can anyone please explain the purpose of a parachute Glossary Link valve installed on a hydraulic cylinder and how it works?

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↑ 0 ↓ kamilrhuadmin 02.07.2012 19:35

The parachute valve, also known as a flow fuse. Its function to shut off the oil that is coming out of the cylinder when the it is rising, falling or holding a load. Widely used in forklifts, car lifters or cranes. The main purpose is to lock the cylinder in motion if the hose connecting the cylinder to the valve control breaks. The valve does not impede or block the flow path in normal operation because it is normally open. But when you have a situation like the breaking of the hose, the flow that leaves the cylinder tends to rise to dangerous levels due to the weight of the load and when the flow exceeds the value set, the parachute valve closes, halting the vertiginous fall.

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↑ 0 ↓ kamilrhuadmin 02.07.2012 19:38

La valvula parachute, tambien se conoce como fusible de flujo. Tiene como funcion cerrar el paso del aceite que sale del cilindro cuando esa linea esta subiendo, bajando o sosteniendo una carga. Muy usada en elevadores de carga, automoviles o en gruas. El principal proposito es bloquear el cilindro en su movimiento si se llega a romper la manguera que esta conectando el cilindro a la valvula de control. La valvula no impide o bloquea el paso del flujo porque es normalmente abierta bajo condiciones normales de trabajo. sin embargo cuando se genera una situacion como la de rotura de la manguera, el flujo que desaloja el cilindro tiende a subir a valores peligrosos debido al peso de la carga y cuando el flujo sobrepasa el valor ajustado en la valvula parachute esta se cierra evitando la caida vertiginosa y sin control de la carga.

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N/A plam 06.04.2012 03:48

Do you know how to adjust the flow level of parachute valve?
Does it need hydraulic test stand,or some spare instrument?

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- ↑ 0 ↓ kamilrhuadmin 06.04.2012 08:37
  
  You can adjust it manually in the machine itself or in a test stand. It is a little complicated due to the fact that there is an internal screw in most of them.
  
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N/A plam 06.05.2012 02:18

Thank you for the information
Right now i have request from customer to supply some hydraulic cylinders with mounted parachute valve.The valves must be adjust for 20 l/min. And i dont know how to adjust the level.I have asked the supplier of the parachute valves,but they are just suppliers.

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- ↑ 0 ↓ kamilrhuadmin 06.05.2012 08:37
  
  Ok, the best way to adjust it is with a flow supply of more than 20 lpm, a flow meter and a flow control. You should know that when the valve receives the adjusted flow or more it closes completely; so the procedure is starting with lower flow (lets say 10 lpm)until it closes taking a close look to the flow meter to be able to read the flow just before it reaches that point.
  If you don't have a test stand or something like it, you still can do it in the machine. Of course, the pump's flow should be less than 20 lpm, the procedure is the opposite. You need to open the adjustment and run the machine a couple of times. Then readjust the valve closing it a little. Try again until the cylinder stops. Then, open the valve and leave it like that. This is an approximate adjustment but it is going to protect the machine against a line rupture.
  
  I hope this explanation is enough.
  
  Camilo
  
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