Pump Universe

Just observe this water droplet. This droplet creates a pressure on the surface it sits. Based on this, please advise how do you define a pressure.  Good Day Everyone, This is Karthik and Welcome to the Pump Hydraulics Basics.  Overview First Things First A quick overview of what we are going to discuss in this series.  Firstly, What is pressure. Then different types/ variants  of pressure.  Secondly, Bernoulli’s theorem and its significance Then, the total differential head and how to calculate them.  More about NPSH and how to calculate them Then finally about Specific speed and Suction Specific Speed. Some datas and myth busters.  Pressure  Pressure is nothing but force per unit area.  The  person swimming in the pool experiencing the force in his ears and his body is the force acting on his body which is a defined area by itself.  Hence, when we talk about pressure, we refer to force acting on an unit area.  The SI unit is ...

Vapour Pressure  Traditionally, we can boil the liquid or turn liquid into a vapour by increasing its temperature and crossing the boiling point. But there is another way of achieving it. i.e., by reducing the surrounding pressure. Just like the example video that I am sharing it with you. ( Wait until the video ends) This phenomenon of liquid turning into a vapour at a particular temperature and pressure is called Vapour Pressure.  What happens when liquid turn into a vapour in a pump ?  You experience what is called a cavitation. Cavitation is a process of liquid turning into a vapour and vapour turning into a bubble. The rumbling sound that you hear in a pump are mostly the cavitation. Just like the animation that I am sharing with you, the bubble implodes/collapses to induce micro cracks on the surrounding parts. Effects of Cavitation Typically, it is impeller that gets affected. Just like what you see in your screen right now. NPSH That’s why Net Positive Suction Hea...

Specific Gravity Have you ever wondered why oil floats above the water if you mix them together, whereas the sand sinks to the bottom, if you mix sand and the water . This phenomenon of liquids/solids floating / sinking under the water due to the difference in the density is called the relative density. As you see in the formula, Ratio of Density of liquid/solids to the density of water is called relative density. If the SG > 1, the liquids tend to be heavier than water If the SG < 1, the liquid tends to be lighter than water. SG & its uses How does it impact the pump system then. Well, it does in two ways. It impacts the pressure head calculations and the shaft power calculations. As you see in the formula,if the head generated by the pump is constant , then the pressure is directly proportional to the specific gravity. i.e, if you run a pump that gives the discharge head of 10m, let’s say the pressure is 1.2 barg for SG 1.2 liquid. The same pump would give the same head, bu...

A quick question to reflect upon : What are the two main components that you observed in the operating principle animation?  First, the impeller adds the the velocity to the liquid or in other words, kinetic energy . At the same time, the centrifugal force that is generated at the centre of the impeller forces the liquid to its edge. Then, the casing converts this moving energy/kinetic energy into the potential energy. Hence, the casing and impeller are the most important components of a Centrifugal pump. Of course the source of the kinetic energy is the motor and shaft is responsible to transmit them to the impeller. Hence they are important too. Then , what are the other parts that are important for reliable Pump operation?  We have mechanical seals to control the leakage and bearings to handle the rotor loads. Pump Performance Curve Now let’s look at the performance curve and reflect on this question,  what do you generally look in a performance curve.  You see, t...

Pump Hydraulics an Introduction Let me tell you a story to begin with.. Once upon a Time, ABC Company has just won a bid for a lube oil pipeline transfer Tender. Mike  the Manager  and John his Junior  are tasked to the design work. They have the experience in handling the water pipeline transfer projects. But due to the company’s restructuring, now they have been tasked to do this lube oil pipe design John , being the junior is unsure whether his estimates are correct. But Mike advises him not to worry and liquids will not play a major role in their calculations. I will let you know what happened to John and his calculations. But let me ask you a question first: Does a liquid property really influence the pump /pipe/system design? Good Day Everyone This is Karthik and Welcome to the Pump Hydraulics – An Introduction. First Things First A quick overview of what we are going to discuss today. Firstly, What is pump hydraulics. What is this session all about Secondly, the o...