Question 66 QMED03 - Oiler

The Correct Answer is D ### Explanation for Correct Option (D) **D) The pump and motor have a common shaft.** This statement correctly describes the defining characteristic of a **close-coupled pump**. In a close-coupled design (also known as a motor pump), the centrifugal impeller is mounted directly onto the extended shaft of the motor. This eliminates the need for a separate bearing frame, an external flexible coupling, and complex alignment procedures. Because the motor shaft serves as the pump shaft, the pump and motor are considered to share a common shaft. ### Explanation for Incorrect Options **A) The pump suction and discharge connections are made with screwed pipe fittings.** Sanitary pumps are designed for easy cleaning (CIP - Clean In Place) and to prevent the entrapment of bacteria. Standard screwed pipe fittings (NPT) are difficult to sanitize because they create small crevices where media can accumulate. Therefore, sanitary pumps utilize specialized quick-disconnect fittings, such as Tri-Clamp, Bevel Seat, or other sanitary clamp connections, rather than standard screwed fittings. **B) The pump housing and motor frame provide for radial adjustment of the shaft coupling.** Radial adjustment is necessary for external, flexible couplings used in *frame-mounted* pumps to ensure proper alignment between the separately supported motor shaft and pump shaft. Since the close-coupled pump uses a common shaft (D is correct) and eliminates the need for a separate flexible coupling, no radial or angular adjustment between shafts is required or provided for. **C) The pump impeller is classified as double suction.** While double-suction impellers exist (used primarily for very high-flow applications to balance axial thrust), the vast majority of standard close-coupled sanitary pumps use a single-suction (or end-suction) impeller design. Double suction is not a universally defining feature of the typical close-coupled sanitary pump construction.