Final answer:
The device required is a flow-through valve that closes the internal self-closing stop valve, shutting off all motion and auxiliary power equipment for cargo tank motor vehicles in metered delivery service.
Step-by-step explanation:
The device required to close the internal self-closing stop valve and shut off all motion and auxiliary power equipment for cargo tank motor vehicles with water capacity of 3500 gallons or less in metered delivery service is called a flow-through valve.
This valve allows water to be drawn in through a lower valve and out through an upper opening, ensuring that 300% of the ballast tank capacity is pumped through. By closing this valve, all motion and auxiliary power equipment can be shut off.
Using a flow-through valve is important for maintaining stability during cargo operations and preventing the need for discharging or entraining ballast water. It is a key component in the proper functioning of cargo tank motor vehicles.