Final answer:
A protective device that stops the operation of a unit due to inadequate fluid flow is called a flow switch. It monitors the fluid's flow rate and acts if the flow is too low, which could signal issues like leaks or blockages. Option C, Flow switch, is the correct answer to the question.
Step-by-step explanation:
A protective device that prevents the operation of a unit when there is inadequate fluid flow is known as a flow switch. This is a critical component in various systems where the flow of a liquid or gas is essential for the proper functioning of equipment.
Unlike a pressure relief valve or a pressure switch, a flow switch is specifically designed to monitor the flow rate and to send a signal if the flow is too low, which could indicate a potential issue in the system such as a leak or a blockage.
The primary function of a flow switch is to ensure that there is a sufficient flow of the fluid before the equipment can operate safely. For example, in a cooling system, if the water flow stops or is too low to cool the equipment effectively, the flow switch would activate and shut down the equipment to prevent overheating and potential damage.
A pressure relief valve, on the other hand, is designed to release pressure from a system when it becomes too high, and a pressure switch is used to sense the pressure level and send a signal based on the pressure condition. A safety interlock is a broader term that could include a variety of devices designed to prevent the operation of equipment under unsafe conditions, but it is not specifically associated with fluid flow.
In conclusion, the correct option for a device that is specifically designed to prevent the operation of a unit when there is inadequate fluid flow is a C. Flow switch.