RU130041U1 - LIGHTING WITH LED FOR STREETS - Google Patents

Abstract

A streetlight illuminator containing an aluminum alloy casing, representing a hollow tube with a cross section in the form of a half ring and a flat base equal to the diameter of the tube and a thickness of 3-10 mm, on the inner surface of the casing there is a seat on which the driver is mounted, on on the outer side of the flat base there are boards with an electric power circuit and LEDs, reflectors and a ceiling made of translucent sheet material convex with respect to the flat base of the case, the radius is half the R rings and the housing length L are determined from the relation, where μ = 1 ∙ 10m / W, η = η / η, η is the light output of the LEDs used; η is the maximum possible (theoretically justified) light output of the LED equal to 250 lm / W; η- driver efficiency; P- power consumed by the LED system, watts.

Description

The utility model relates to lighting devices with LEDs and can be used for the manufacture of powerful street lamps with cantilever mounting on a support and with a luminous flux of at least 6000 lm.

Known LED illuminator, described in RF patent No. 96696 for utility model "LED lamp with highly efficient convection cooling", published on 08/10/2010, 02/18/2010, IPC Н01Н 33/00. The lighter is used to illuminate the streets, it contains powerful LEDs as a light source, an LED power supply, a ceiling and a radiator body made of a hollow profile in the form of vertical fins, LEDs are mounted on the outer surface of the housing and are electrically connected to the power supply, and the plafond is mounted on the outer surface of the housing, closing the LEDs.

As can be seen from the above description, the LED illuminator contains a radiator case, the surface of which is made in the form of vertical fins. The manufacture of such a surface is a significant technological difficulty, and during the operation of the illuminator, significant amounts of debris and dust accumulate between the grating ribs in a short time, which requires regular cleaning of the illuminator and greatly complicates its operation.

A well-known streetlight with LEDs, manufactured by the Lumen Light Company (Russia, Moscow), "Azimut-60 Street LED Lamp, consol / 3-UAz60.html" on May 24, 2012. The light contains metallic (in particular - aluminum) casing in the form of a pipe in the cavity of which the driver is installed. On the opposite sides of this body, directly against the pipe cavity, two identical plane-parallel plates are rigidly fixed so that their side edges are connected directly against the cavity of this pipe, and the plates themselves are in the same plane orthogonal to the diameter of this pipe. On each plate on one side there are installed LEDs with a luminous efficiency of 112 lumens / W each and boards with an electric power supply circuit for the LEDs, moreover, all these LEDs are installed according to the well-known technology that ensures heat transfer from the LED through a layer of heat-conducting substance to the case. All LEDs during operation create a luminous flux of 6000 lumens and consume 60 watts of electrical energy. On the side of each of the plates without LEDs, ribs are made, located along the illuminator body, mutually parallel to each other and evenly spaced apart from the plane of this plate. Due to the presence of fins and plates, the illuminator has large weight and size characteristics, is difficult to manufacture and inconvenient to use - debris and dirt accumulate on the plates between these ribs over time, which significantly reduce the heat transfer of the case and therefore they need to be cleaned regularly.

The closest known one is the SVETECO-96/10752/120 brand LED street light, manufactured by Ledel LLC - Russia, the Republic of Tatarstan, Kazan, website 03.04.2012

The luminaire contains a continuous aluminum casing, in the body of which two through cavities are made, having the shape of a pipe and located parallel to each other along the casing. Three aluminum plates, having the form of a ruler, are fixed on one side of the housing, each LED has a single row of LEDs installed on each of the plates, and all of these LEDs are installed using the well-known technology that transfers heat from the LED through a layer of heat-conducting substance to the housing. Aluminum plates are tightly attached to the illuminator body with the side without LEDs, all of them are located so that the LEDs installed on them are in the same plane, and their light-emitting windows are directed in the opposite direction from the body. On the surface of the lamp housing from the side where there are no LEDs, a driver is installed and metal ribs are made evenly spaced on this surface, which creates a high heat sink area from the LEDs. Due to the presence of fins, the luminaire has large weight and size characteristics, is difficult to manufacture and inconvenient to use - between the ribs, debris and dirt accumulate over time, which significantly reduce the heat transfer of the housing and regular cleaning.

The objective of the utility model is to simplify and reduce the cost of the lamp in the manufacture and operation.

The task is solved by a streetlight illuminator with a housing made of aluminum alloy, which represents a hollow pipe with a cross section in the form of a half ring and a flat base equal to the diameter of the pipe and a thickness of 3-10 mm. On the inner surface of the housing is a seat on which the driver is mounted. On the outside of the flat base there are boards with an electric power circuit and LEDs, reflectors and a ceiling made of translucent sheet material convex with respect to the flat base of the case, the radius of the half ring R and the length L of the case are determined from the ratio

,

,

where µ = 1 × 10 ^-3 m ² / W,

η _c = η / η _T ,

η is the light output of the LEDs used,

η _T - the maximum possible (theoretically justified) light output of the LED, equal to 250 lm / W,

η _PRA - driver efficiency,

P _with - the power consumed by the system of LEDs, watts.

Figure 1 shows a cross-sectional diagram of a illuminator. A street light fixture comprises an aluminum alloy housing 1, which is a hollow tube with a cross section in the form of a half ring and a flat base 2 equal to the diameter of the tube and a thickness of 3-10 mm. A seat is made on the inner surface of the housing, on which the driver 3 is fixed. On the outer side of the flat base 2 there are boards with an electric power circuit and LEDs 4, reflectors 5. A shade 6 made of translucent sheet material convex with respect to the flat one is attached to the housing 1 the base of the body. The radius of the half ring R and the length L of the housing are determined from the relation

,

,

where µ = 1 × 10 ^-3 m ² / W,

η _c = η / η _T ,

η is the light output of the LEDs used,

η _T - the maximum possible (theoretically justified) light output of the LED, equal to 250 lm / W,

η _PRA - driver efficiency,

P _with - the power consumed by the system of LEDs, watts.

As you know, the heat generated by the LEDs and the driver is removed through the walls of the housing to its surface, it should be quite large. Previous studies show that when an electric energy of more than 70 W is supplied to the illuminator, such an amount of heat is generated that it is necessary to make ribs on the illuminator body to increase the area of exchange with the medium.

The analyzed process of transferring heat of electric energy to the LEDs showed that in the case of modern LEDs with high light output, no more than 50% of electric energy is transferred to heat, and the rest of it goes into the light flux and is scattered in space without heating the volume, in which the LEDs are located. By calculation and by computer simulation, it was found that when applying electric energy with a power of more than 70 W to LEDs with a driver, for effective heat removal, it is necessary that the geometric dimensions of the lamp housing be in a certain ratio, namely, the ratio of the external radius R and the length L of this housing.

The thermal resistance of the heat-conducting element - in our case, the walls of the illuminator body - determines the temperature difference that arises between the fuel element or the system of fuel elements - in our case, the system of LEDs - and the environment surrounding the system of fuel elements

where ΔT is the difference between the ambient temperature and the average temperature of the radiator ΔT = (T _rad -T _shift ),

P _in - power generated by the system of fuel elements.

Thermal resistance in convective heat transfer is determined by the expression

where α is the heat transfer coefficient, expressed in units of W / (m ² K),

S _P - lamp housing area, expressed in m ² .

From the expressions (1) and (2) it follows ΔT / P _in = 1 / (α × S _p ). Hence, S _P = P _in / (α × ΔT) (3)

If P _c is the power consumed by the radiation LED system, then P _c = P _in + P _out , where P _out is the power of light radiation. Depending on the light output η _s = Ф / Р _s (lm / W), where Ф is the luminous flux emitted by the LED system, power Р _в = (1-η _s / η _t ) × R _s , where η _t is the maximum possible theoretically justified light output of the LED equal to 250 lm / W (Schubert F. LEDs / Transl. from English. Edited by A.E. Yunovich - 2nd edition. - M. FIZMAT LIT, 2008. - 496 s) . Then:

The typical value of ΔT should not exceed 30 ° C, then:

R _T = 30 / ((1-η _c / 250) × P _c )

In natural convection, the heat transfer coefficient a is in the range from 6 to 10 W / (m ² K). Typically, in preliminary calculations, α = 10 W / m ² K.

In accordance with figure 1, the surface of the housing through which convective heat transfer is carried out, can be approximated by a semi-cylindrical surface. Then this area will be approximately equal

where R is the radius of the pipe, L is the length of the pipe

From (4) and (5):

(1η _c / 250) × P _c / (α × ΔT) = π × R × L.

From here:

R × L = (1-η _c / 250) × P _c / (α × ΔT) / π

or, substituting data

R × L = (1-η _c / 250) × P _c / (10 × ΔT × π) or

To take into account the power released by ballasts - the driver, it is necessary to add to the power consumed by the light part of the lamp, a value equal to (1-η _pra ) × P _s ,

where η _pra - the efficiency of ballasts. Then:

The above calculations are confirmed by computer simulation and experimental data.

This design of the illuminator body greatly simplifies the technology of its manufacture, since all metal parts can be manufactured by extrusion, greatly simplifies its operation - dirt and debris that do not need to be cleaned regularly collects on the surface of the body. In addition, using the expression obtained, it is possible to calculate the length of the housing for a given cross section for any power consumed by the lamp.

Claims (1)

A streetlight illuminator containing an aluminum alloy casing, representing a hollow tube with a cross section in the form of a half ring and a flat base equal to the diameter of the tube and a thickness of 3-10 mm, on the inner surface of the casing there is a seat on which the driver is mounted, on on the outer side of the flat base there are boards with an electric power circuit and LEDs, reflectors and a ceiling made of translucent sheet material convex with respect to the flat base of the case, the radius is half ring R and the length L of the housing defined by the ratio $$R\times L=\mu \times \left(2-{\eta }_c-{\eta }_{PR\mathrm{BUT}}\right)\times P_{\mathrm{from}}$$

, where µ = 1 ∙ 10 ^-3 m ² / W, η _c = η / η _T , η is the light output of the used LEDs; η _Т - the maximum possible (theoretically justified) light output of the LED, equal to 250 lm / W; η _PRA - driver efficiency; P _with - the power consumed by the system of LEDs, watts.

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