The advantage of using a venturi tube, rather than an orifice plate for flow measurement is it:

The advantage of using a venturi tube over an orifice plate for flow measurement primarily lies in the characteristic of producing less permanent pressure drop. A venturi tube is designed with a gradually constricted flow area that allows for a smooth transition in flow velocity, which minimizes turbulence and losses. This design allows for the maintenance of a higher pressure downstream compared to the abrupt opening created by an orifice plate.

The lower permanent pressure drop associated with venturi tubes leads to improved efficiency in systems where maintaining pressure is crucial, such as in refrigeration and other fluid handling applications. This aspect can also contribute to lower energy costs and reduced strain on pumps and other system components, as less work is required to maintain the desired flow rate.

The other aspects related to bulkiness, number of pressure taps, and installation costs can vary depending on specific conditions and applications, but the predominant and widely recognized advantage of the venturi approach is its superior ability to minimize pressure losses in the system.