What Is Capillary Action? Expression for Capillary Rise/ Fall?

capillary rise and fall

What is meant by capillary?

Capillary is a phenomenon of rising or falling of liquid surface in a small tube compared to the adjacent normal liquid level. The rise of liquid in tube known as capillary rise while depression of fluid level is known as capillary fall. Capillary depend upon density of liquid, surface tension of liquid and the diameter of the tube. The example for capillarity: blotting paper absorbing ink/water, chromatography, water absorption by sponges, soil water rises to surface by capillarity.

Governor Controlling Force and Controlling Force Diagram

Governor Controlling Force and Controlling Force Diagram

Controlling force

When governor running each ball of the governor subjected an inward pull. Consider a governor running at a steady speed, then the inward force acting on the rotating governor ball is known as controlling force. Controlling force of governor is equal and opposite to the centrifugal reaction.
Controlling Force, Fc = mω2r

In porter governor controlling force is provided by the weight of sleeve and balls. In spring controlled governor (eg: Hartnell governor) controlling force provided by spring and weights.

What Is Meant By Effort And Power Of A Governor?

effort power governor

Read: What Is A Governor?

Governor effort and governor power are the tools that can be used to compare different type of governor.

Effort of Governor

Effort of governor is defined as the mean force exerted at the sleeve of governor for a given percentage of change in speed of spindle or lift of sleeve. When governor running at constant speed, the force exerted on the sleeve is zero. When the governor speed changes the spindle moves up or down to new equilibrium position. There will be a force that prevents this movement of sleeve. The resistance is equal to Effort of governor. This resistance varies from maximum to minimum as the sleeve moves to the new equilibrium position.

Pickering Governor Construction and Working and Equations

Pickering Governor diagram

Construction and working of Pickering Governor

Pickering governor is very simple in construction and it is used for small machines. The sleeve movement in Pickering governor is very small when compared to the other centrifugal governor. It controls the speed by dissipating excess kinetic energy.

Wilson-Hartnell Governor Construction and working

willson-hartnell governor
Read: Construction and working Hartnell Governor

Construction and working of Wilson-Hartnell Governor

A Wilson-Hartnell Governor is shown in above figure. In this type of governor has a primary/ main spring and an auxiliary spring. The main spring arranged symmetrically on either side of the axis and it connects two flying balls on the vertical arms of bell crank lever. The horizontal arms of bell crank lever carry rollers which press against the sleeve of governor. An adjustable auxiliary spring is attached to sleeve mechanism of governor through a pivoted lever.  The Purpose of this auxiliary spring is that to adjust the equilibrium speed for a given radius of rotation. The auxiliary spring tends to keep sleeve down.

Hartung Governor Construction, Working and Equations

hartung governor image
Read: What is the purpose engine governor?

Construction and working of Hartung Governor

Hartung governor is a type of spring controlled governor. The various parts of a Hartung governor are indicated in above figure. The bell cranks are pivoted at O, O’ to the frame. The horizontal bell crank livers are attached to the roller fits into the grooves of the sleeve. Sleeve is free to move up and down along the central axis of Hartung governor by two keys. The vertical arm of bell crank lever is fitted with spring balls which compress against the frame of the governor. The spring opposes the centrifugal force acting on the spring balls.