Espresso machines, it’s now possible see espresso bars at the restaurants and bars as the number of those who appreciate a cup of espresso have substantially increased. First, ground coffee is filled into the filter holder. The correct quantity for a cup is 7 grams. The grinds are lightly tamped. Then the filter holder is placed in the machine and press the button.
Approximately 95°C. high pressure water is forced through the grinds and caramel colored highly aromatic coffee starts to fill the cup. One may think that all the accessories on the machine do the trick. But actually the secret is hidden inside. An espresso machine consist of a few parts. A water reservoir. A portable filter holder and a steam wand, and this is where you place the cup.
The First Thing To Do Is To Fill The Water Reservoir
As soon as it’s filled, the water pumped into the boiler. When the espresso machine is turned on, electricity starts to work. The current passes through the thermostat and arrives to the heater in the boiler. It instantaneously starts to heat the water. The water is heated approximately 95 degrees celsius, in other words, a touch shy of boiling point.
The goal here is to reach the highest possible water temperature without reaching to the boiling point because if boiling water is used, the grinds get burned resulting in a bitter taste and bad aroma. The ideal water temperature for brewing coffee is 95 degrees celsius.
When the water temperature reaches 95 degrees celsius, the thermostat contacts open and cut current to the heater. Then the thermostat the current to the control panel. When the light is on, the machine is already. When the button is pressed, the pump starts to work creating an electromagnetic force that moves the piston.
It works at an enormous pressure of 15 bar, which is 3 times higher than the pressure in a champagne bottle and equal to the pressure at a depth of 140m which could be dangerous for divers. The water is first forced down to the tank below, then though the filter holder and finally espresso fills the cup. Espresso machines. In today’s world, at homes, cafes, coffee shops and everywhere.
Sonar Devices
In other words fish finders that use sound waves. These devices are mounted at the stern of the boats and allow us to locate schools a fish. Just like dolphins do to communicate, fish finders use sound waves. Then they receive the reflection of the wave and locate the point of reflection. A fish finder is comprised of three basic components. A main card, a transmitter receiver converter and a screen.
The transmitter receiver converter is mounted underwater at the stern of the boat. Activated fish under first transmits a signal or a pulse. For this, current the main board sends is converted to sound waves by the converter. Sound is a kind of energy which propagates in circular waves. Sound waves don’t propagate in vacuum. They need particles in the medium to do so.
Since there is no particles in a vacuum, energy can not be transferred and sound waves can not propagate. Water particles incited by sound waves vibrate, the vibration is transferred one particle to another resulting in the propagation of the sound waves. Sound waves move quite fast. The frequency range of the sound waves transmitted by sonars is 50 kHz – 200 kHz which is too high for human ear to hear.
The Pulses Cannot Be Heard By The Fish Either
When sound waves sent underwater hit something they reflect creating an echo which received by the sonar and allows us to see what is under the sea within a certain range. The converter converts sound waves to electricity and this process is repeated many times in a second.
In other words, many pulses are transmitted and many echoes are received every second and that allows us to see al the details underwater in the screen including the size and distance of a detected object. As a result, sonar devices they allow us to see underwater using sound waves.
Infrared Thermometers
They infer temperature using a portion of thermal radiation emitted by the object of measurement. These thermometers which measure the temperature using thermal radiation that is invisible to us, are ready for use day or night showing the measurement on their digital screens. This battery powered one has five components. An infrared detector located on the front of the device.
A screen light indicator located next to it. An LCD screen. A display button and an ambient temperature indicator. A non contact thermometer generally works by detecting the thermal radiation that the object of measurement emits by a sensor. A lens gathers infrared thermal energy emitted by the object. For this, all you have to do is to press down the button on the side of the thermometer.
Then, the thermal energy is focused by a fresnel lens onto the detector. The detector converts the radiant power to an electrical signal and this signal is sent to a micro processor which calculates the temperature and finally the result of the calculation is displayed on the LCD screen.
The whole process takes about a second. The measurement range varies from 100 to 5000 degrees celsius depending on the device. Whether the object of measurement is glossy or mat can be important as a glossy object will reflect the energy from surrounding objects which may affect the measurement. Therefore, it is ideal to use it on dark colored objects with mat surface. This system can measure the temperature of any object without contacting it.
