Complex triangular relationship in LED lighting

Usually I often hear questions from Party A or the designer: What is the beam angle of this luminaire? Is there wood? Then the salesperson of the manufacturer said according to the data, how much is this angle. The sample light is on, it’s all dumbfounded. Is there wood? Who is the geometry? How can this light be 12°, and how can it look like 30°? Party A and the designer kept shaking their heads to express dissatisfaction, and the salesman was downcast and speechless. Is there such a scene?

Or someone asked: What is the cut-off angle of this luminaire? The cut-off angle, you don't know how to have wood? You are not easy to answer up. At first glance, this glare is very powerful. How could it be a 60° cut angle? You can't answer it, is there a wood? Is there wood? ? ?

Ok, let's take a look at this triangular relationship that makes communication between you and your customers always cause problems.

First, the beam angle

A picture is worth a thousand words. Beam angle refers to the angle between two directions in which the luminous intensity is equal to 50% of the maximum intensity on a plane of the vertical beam centerline.

This parameter is commonly used to measure the light intensity distribution of reflective light sources, spotlights, and downlights with narrow angles.

The point of doubt: the beam angle does not refer to the full beam inclusion angle, so the spot that is shot cannot be the angle between the line from the center of the lamp to the outer edge of the spot and the line from the center of the lamp to the center point of the spot.

Advanced: Is it tested with a illuminometer, and the point where 50% illumination is 50% direct? The answer is: NO! According to the cosine law and the inverse square law, under ideal conditions, the illuminance value Ep of the point where 50% of the light is directly reflected should be:

In addition: outdoor lighting often makes the acceptance angle of 1/10 peak light intensity the beam angle of the fixture.

Second, the shading angle (protection angle shielding angle)

1, or a picture wins a thousand sentences. The shielding angle of the luminaire refers to the angle between the line connecting the edge of the light source and the edge of the opening of the luminaire.

Third, the cut angle

Note: The cut-off angle of the fixture is often confused with the shading angle, but the difference is a thousand miles, which is actually the corner of the shading angle. I am too lazy to take pictures, but I will not talk nonsense. I will understand the above picture.

The shading angle and the cut-off angle, which are commonly used to control the glare of the luminaire, are necessary parameters for measuring the visual comfort of the luminosity distribution of the luminaire. Outdoor street lights directly use the cut-off angle to measure the glare level of the fixture.

Interpretation point: The luminaire with a protection angle of 30° (cutting angle of 60°), why stand at the geometrical position of the line of sight of 30°, is still so glaring? Above picture.

From the figure we can see that the light of the luminaire, in addition to the direct light source may cause glare, the reflected light on the surface of the lamp cavity material may also cause glare. In addition, the overall brightness of the surface of the luminaire may also cause glare on the surface of indoor materials, especially computers.

In general, light environment glare control is a systems engineering. Just looking at the protection angle is obviously not enough, and now many lighting designers use the beam angle to measure the glare control of the luminaire, which is a bit simple and rude. If you have the conditions, you should still look at the light distribution curve of the luminaire.

Rice Cooker

A rice cooker or rice steamer is an automated kitchen appliance designed to boil or steam rice. It consists of a heat source, a cooking bowl, and a thermostat. The thermostat measures the temperature of the cooking bowl and controls the heat. Complex rice cookers may have many more sensors and other components, and may be multipurpose.  Cooking rice has traditionally required constant attention to ensure the rice was cooked properly, and not burnt. Electric rice cookers automate the process by mechanically or electronically controlling heat and timing, thus freeing up a heating element on the cooking range that had to be otherwise occupied for rice cooking. Although the rice cooker does not necessarily speed up the cooking process, with an electric rice cooker the cook's involvement in cooking rice is reduced to simply measuring the rice, preparing the rice properly and using the correct amount of water. Once the rice cooker is set to cook, the rice will be cooked with no further attention.

Features:

For modern home rice cookers, the smallest single-person model cooks 1 rice cup (180 ml), whereas large models can cook 10 cups. Commercial models can cook 20 or more cups. As a possible source of confusion, model specifications and names may list either cooked or uncooked capacity. Rice roughly doubles in size during cooking; therefore, a 10 cup (uncooked) rice cooker can produce up to 20 cups of cooked rice. The prices vary greatly, depending on the capacity, features, materials used, and the country of origin.

The majority of modern electric rice cookers are equipped with a stay-warm or keep-warm feature, which keeps the rice at an optimal temperature for serving without over-cooking it. Some gas cookers also have electric stay-warm mechanism. However, the usefulness of this feature degrades over time, a microwave may be more energy efficient or better suited to reheat rice that will sit longer than four hours.

Some rice cookers use induction heating, with one or more induction heaters directly warming the pot. This can improve energy efficiency.

Most modern rice cookers use aluminium for the inner cooking bowl. There are some models that use stainless steel instead of aluminium. Various other materials, such as copper, pure carbon, ceramic, and diamond powder coating, may be used for higher heat conductivity or better taste.

The pressure-cooking models can raise the water's boiling point higher, e.g., from 100 °C at 1.0 atm up to about 110 °C at 1.4 atm, which speeds cooking. The pressure-cooking models can also be used in high altitude areas, where the boiling temperature is below 100 Celsius. Pressure cookers are also suitable for cooking brown rice (which contains oils and bran fiber that cook differently from pure white rice starch). Some pressure rice cookers have a varying pressure control mechanism (named the "dual-pressure" method) that creates repeated pressure/release cycles during the cooking.

There also exist mechanisms to collect and return the boiled over liquid to the inner rice bowl.

Many cookers now have microprocessor-controlled cooking cycles, which are often used to adjust for rice and cooking type.

Applications

Rice cookers are typically used for the preparation of plain or lightly seasoned rice. Each rice cooker model may be optimized to cook a certain type of rice best. For example, most Japanese rice cookers are optimized for cooking Japanese rice and may not be the best for other types of rice[citation needed], although cooking time can be lengthened simply by more water.

The typical method of cooking long grain rice is boil-and-strain and/or steaming method. The absorption method used in Japanese rice cookers will produce slightly different texture and taste, usually stickier rice.

Brown rice generally needs longer cooking times than white rice, unless it is broken or flourblasted (which perforates the bran).

Different varieties of rice need different cooking times, depending on their grain size, grain shape, and grain composition. There are three main types of Asian rice: Oryza sativa subsp. indica, i.e., Indian rice (long grain rice, e.g., basmati rice and Thai jasmine rice), O. sativa subsp. javanica, i.e., Java rice (large grain rice) and O. sativa subsp. japonica, i.e., Japanese rice (medium grain rice, e.g., Calrose rice, short grain rice, e.g., most Japanese rice and risotto rice).

African rice, Oryza glaberrima, is an entirely separate species, but can be cooked in the same way. Zizania is not even in the same genus, although it is often called a rice (or "water oats"); it, too, can also be cooked in a rice cooker.

A rice cooker can be used to cook many boiled or steamed granular foods, such as pot barley, bulgar wheat, and dal. Provided the ingredients have similar cooking times, a rice cooker can cook mixtures such as khichdi. Some rice cookers can be used as automated couscoussiers, cooking couscous and a stew simultaneously.

Rice Cooker

Rice Cooker,Drum Rice Cooker,Deluxe Rice Cooker,Straight Rice Cooker

Guangzhou Taipeng Electrical Appliances Technology CO., LTD. , https://www.taipengelectric.com