Pumps - The Hydraulic Source

Chapter: 4

Pumps - The Hydraulic Source

"The real problem is not whether machines think but whether men do."

- Joseph Snipp

"Wisdom is the reward of listening... when you'd have preferred to talk." 

- D.J. Kaufmann

"Two things are infinite: the universe and human. stupidity; and I'm not sure about the universe.

- Albert Einstein

"I invent nothing. I redis- cover."

- Auguste Rodin

Learning Objectives

While reading and after studying this chapter, you will be able to:

• Understand the principle and uses of the hydraulic pumps.

• Differentiate between positive displacement and non-positive displacement pumps.

• Describe and appreciate the principle, construction, operation, advantages, limitations, and applications of various types of gear, vane, and piston pumps. 

• Distinguish between fixed displacement and variable displacement pumps.

• Compute the volumetric displacement and theoreti- cal discharge of the various positive displacement pumps.

• Evaluate the pumps' performance by computing the various pump efficiencies.

• Analyse and compare the characteristic curves and the various performance factors of different pumps.

• Select the appropriate hydraulic pump for a specific application.

1. INTRODUCTION

As discussed in Section 1.7, any hydraulic system requires six basic components: reservoir, pump, electric motor (or prime mover), valves, actuator, and fluid-transfer piping. Though each of these components is very essential for proper functioning of the system, the pump is extremely important component to facilitate transfer of power and motion. In fact, the hydraulic pump is said to be the heart of the hydraulic system.

In this chapter, we shall discuss the construction and working of different types of pumps, their typical applications, selection, and performance.

1. What is a Hydraulic Pump?

• Definition: A hydraulic pump is a device which converts mechanical energy into hydraulic energy.

• The pump is used to impart motion to a liquid. It provides the force required to transmit power and motion.

• The pump does not produce pressure. It produces only fluid flow.