Which type of valve is used to prevent jack overload?

The correct answer is the pressure relief valve, which plays a crucial role in preventing overload conditions in hydraulic jacks. This type of valve is designed to open at a predetermined pressure limit, allowing fluid to escape from the system when the pressure exceeds safe levels. By diverting excess fluid, the pressure relief valve protects the jack from damage that could occur due to over-pressure scenarios, ensuring operational safety.

The pressure relief valve acts as a protective feature, maintaining system integrity and preventing the risk of catastrophic failure. It's important to understand that while safety valves and pressure regulators also play protective roles in hydraulic systems, they have different functions. A safety valve is typically used in scenarios where a total failure of pressure regulation could occur, while a pressure regulator valve modulates the pressure within a system to maintain a specific output without addressing overload situations directly. Flow control valves regulate the speed and direction of fluid flow rather than serving as a protective mechanism against pressure overload.

In summary, the pressure relief valve is specifically designed to handle overload situations in hydraulic jacks by releasing excess pressure, thus safeguarding the system and ensuring safe operation.