DE2522209A1 - HIGH PRESSURE SODIUM VAPOR LAMP WITH LOW STARTING VOLTAGE - Google Patents

Description

GTE-Sylvania Incorporated, LJ.3.A. May 14, 1975

GTE-PA 46

PATENT APPLICATION

High pressure sodium vapor lamp with low ignition voltage

The present invention relates to a high pressure sodium vapor lamp with low ignition voltage using an alumina arc tube, which is mounted within an outer glass envelope of the lamp, with the arc tube attached to each End has an electrode and a filling of sodium, mercury and a gas mixture and has a device for starting aid is provided.

In recent years, high-pressure sodium lamps have been particularly popular because of their high efficiency Commercial lighting systems used outdoors. The vapor pressure working with sodium in such lamps can range from a few millimeters to about 1000 millimeters Mercury vary.

In contrast, work low pressure sodium vapor lamps that have been known for several decades and are also of good efficiency, with sodium vapor pressure of the order of magnitude less

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thousandths of a millimeter Hg. The light they emit has an unattractive color. The light color the high pressure sodium vapor lamp, however, is opposite the low pressure sodium vapor lamp is significantly improved.

The high pressure sodium vapor lamps of the previous designs usually contain an aluminum oxide arc tube and a filling of the same made of sodium, Mercury and one carry gas, usually xenon. Examples of these lamps are U.S. Patents 3,248,590, 3.721.846 and 3.746.914 can be found. The Larrpen have one major disadvantage: they are only start with a significantly higher ignition voltage than other discharge lamps, e.g. fluorescent mercury vapor or metal halide lamps. This higher ignition voltage makes a more resilient Special ballast necessary.

The present invention was therefore based on the object of providing a high-pressure sodium vapor lamp with a lower Create ignition voltage that does not require any special ballast.

There are already such lamps with a reduced ignition voltage by heating the arc tube has become known from the latter two of the aforementioned US patents. These solutions already allowed the use of the common ballast arrangements for mercury vapor lamps and were thus easier

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and more economical.

The present invention was based on the further object of simplifying these known lamps and thus enable cheaper production.

According to the invention, these tasks are carried out for the generic term specified according to the identifier of the Main claim solved.

Further details can be found in the subclaims and the description of a preferred exemplary embodiment refer to.

The application of the well-known Penning effect, who was already in the 20s by F.M. Penning was discovered and states that certain gas mixtures have lower ignition voltages than the individual Gases separated, led to beneficial ones with mercury vapor, fluorescent and low pressure sodium lamps Applications in the past.

Permitted to use with high pressure sodium vapor lamps Penning gas mixtures dispense with preheating of the arc tube. It can with a simple jump starter consisting of a wire ring near the lower electrode and at room temperature over one lying in series Bimetal thermal switch at the potential of the more distant, upper electrode is to be ignited.

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After the lamp has warmed up accordingly, the thermal switch opens and the starting aid is de-energized .

For a better understanding of the invention should first the Penning effect can be explained by the appropriate Discuss terminology and some basic concepts about gas atoms.

Let us first consider an atom in its ground state. This is the normal state of the atom with a full complement of electrons swirling around the nucleus in their normal circles.

When enough energy (the excitation voltage) is supplied to the atom, an electron goes into one higher energy level or orbit above. This is known as the excited state of an atom. A Atom in the normally excited state tends to return to the ground state fairly quickly. Included gives off energy in the form of radiation or light.

At special energy levels (the metastable potential) an atom is excited, but tends to to remain in this state. It can actually stay 1000 times longer in its aroused state as the atom of the normally excited state. This is known as the metastable state.

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Metastable Alamo tend to get their energy through Colliding with other atoms instead of being lost by radiation.

When higher voltages are applied to the atom, the electrons move completely away from the atom. The atoms then become charged ions. The atom is then in the ionized state, and so is the energy level or the potential required to form ions is known as the ionization potential.

For further explanation, reference is made below to the drawings.

FIG. 1 shows a preferred one according to the invention Embodiment of a high pressure sodium vapor lamp;

Figure 2 shows a graphical overview for

the lowest metastable voltages, the lowest excitation potential and Ionization potential of various Gases or vapors;

Figure 3 shows a curve showing the effect

the attachment of a starting aid designed as a wire ring in an inventive Lamp reproduces.

Reference is first made to FIG. It shows an overview in which the lowest metastable Tensions, the lowest potential for excitation and the ionization potential of various gases or vapors commonly found in arc discharge lamps

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such as neon, argon, xenon, mercury and sodium, can be compared with one another. The lower one, solid line represents the lowest metastable potential; the dashed line is that lowest arousal potential. The upper solid line indicates the ionization voltage of the gas.

In order for the Penning effect to take place, must certain requirements must be met:

1. It rr.uß a smaller and larger. ' ^-r ier portion of the gas mixture exist;

2. The lowest excited state of the major part must be metastable;

3. The metastable voltage of the main component must be greater than the ionization potential of the smaller proportion.

In view of the fact that we get the best possible subscription ratio from the larger and smaller share can choose, it can be seen from Fig. 2 that different Penning fishes are possible. Under them is argon as the main part with mercury. This mixture is used in fluorescent and mercury vapor lamps used.

Another possibility is neon as the main component with argon. This is the ignition gas mixture that is used for High pressure sodium lamps with the Penning effect start is selected. Typical Penning mixtures from neon

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Argon gases contain argon as approximately 0.1 - 1 percent of the mixture. So we can do 100 to 1000 times more Expect neon atoms to be argon atoms.

Let us consider arbitrary electrons that are in an arc tube with the neon-argon mixture mentioned above be accelerated. The probability of colliding with neon atoms is greater than with argon atoms, since the number of the latter is very small. It is very likely that a few electrons up to a speed corresponding to a kinetic energy of 16.6 V, can be accelerated before colliding with neon atoms. So they were giving their energy to that Give up neon atoms and cause them to come into the metastable state. As this is the lowest excited state of the main part, it is very likely that this situation is sufficient will be present. The neon atoms tend to collide in their excited metastable state to remain. When they collide and give their energy to the argon atoms, so will this ionizes. This is because the energy imparted by the neon atom is greater than 15.8 V, which are required to ionize the argon atoms. This process continues until the gas ionizes and current flows, which ignites the lamp.

The use of a Penning mix reduced according to the invention already largely the starting voltage

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compared to the conventional high-pressure sodium lamp filled with xenon. Jedoferi / d ^ s not yet about one satisfactory ignition with mercury ballast bring about. To construct lamps that are capable of operating at voltages caused by a mercury ballast are supplied to ignite, a starting ring is therefore according to the invention around the arc tube placed. The starting ring, which is located near an electrode, has the voltage the other, opposite electrode. This will appear between the starting ring and the nearby electrode this short distance the full open circuit voltage is effective. The ionization is initiated in this way and then tends to avalanche towards the opposite electrode.

A lamp according to the invention as shown in FIG contains an airtight aluminum oxide tube 1 in an outer glass envelope 2, which is attached at the bottom to the extension of the usual pinch foot 3 and the conventional base 4 with metal thread. The lead wires 5 and 6 are stored in the pinch foot 3 and with the Base 4 connected in the usual way.

The support rod 7 is soldered to the insertion wire 5 and extends through from below to above the whole lamp. The upper end of the arc tube 1 is held by a rod 8 which is placed between the Support rod 7 and the niobium tube 9 is soldered.

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The tube 9 is closed by the upper end of the arc tube 1 and carries the electrode 10 in the arc tube 1. The electrical connection to the electrode 10 is established through the metal web 11 · placed, which is soldered between the rod 7 and the niobium tube 9.

The lower end of the arc tube 1 is supported by the metal web 12 that holds the lower niobium tube 13 securely encompassed and soldered to the insertion wire 6 is. The tube 13 is closed by the lower end of the arc tube 1 and supports the electrode inside the arc tube 1.

The starting aid 15 consisting of a wire ring surrounds the arc tube 1 as an electrode and is the lower end of the tube closer than the upper. The starting aid 15 is thus in the vicinity of the lower one Electrode 14 and far away from the electrode The wire ring 15 is soldered to a retaining wire 16, which is embedded in a quartz rod 17. This is supported by a further support wire 18 worn, which is mounted on her and soldered to hold the rod 7. Another wire 19 is embedded in the quartz rod 17 and also soldered to the rod 7. A U-shaped bent bimetal switch 20 is soldered to wire 19 and makes pressure contact with wire 16 at room temperature here. Thus the wire ring 15 has the same voltage as the electrode 10 when the lamp is initially energized will. The wire ring 15 is opened by opening the

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Switch 20 is electrically taken out of the circuit, what happens when the switch 15 by the heat generated in the lamp to its switching temperature, e.g. 105 C, is heated. The removal of the wire ring 15 from the circuit is necessary to avoid electrolysis from occurring through the walls of the during normal operation Arc lamp could draw sodium into this.

At the lower end of the lamp are two getters 21 which are supported by the rod 7. The sprung Fingers 22, located at both ends of the lamp and mounted on the rod 7, grip the Inner wall of the glass jacket 2 and help to bring the arc tube 1 into the correct position. the

the
Wall thickness cannot be seen from / drawing. Only the outer contour of the glass bulb 2 is shown.

The arc tube 1 contains sodium, mercury and a filling of a Penning gas mixture such as neon and Argon.

The attachment of the starting aid 15 consisting of a wire ring is critical for achieving the lowest ignition voltage.

The effect of the distance between wire ring 15 and electrode 14 on the ignition of a particular 15Q-W lamp is shown in FIG. The arc length of the lamp was approx. 69 mm. The location shown in FIG. 3

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The jump start is the distance between the wire ring 15 and the electrode 14. The most favorable position in this example was a distance of about 17 mm.

The best place to jump start depends on the pressure and composition of the Penning gas mixture. In an arc tube with an arc length of 69 mm, which is 14 torr. Contains 99% neon and 1% argon, for example, the lowest ignition voltage of 160 V was achieved at a starting point with a distance of 24.1 mm. For a Penning mixture of 99.7% neon and 0.3%
Argon at 34 torr. the starting aid 15 was attached at 16.2 mm - in order to obtain the lowest ignition voltage.

The embodiment described is a preferred one
Exemplary embodiment. However, for the
Experts are close to other trainings that the
Do not leave the inventive idea.

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Claims (3)

Claims ; (1 ..) A high pressure sodium vapor lamp with low ignition voltage, which is an aluminum oxide arc tube used, which is mounted within an outer glass envelope of the lamp, with the arc tube at each end of the glass an electrode is seated and a filling made of sodium, mercury and a gas mixture has, and a device for starting aid is provided, characterized in that the Gas mixture is a so-called Penning gas mixture, known per se, that the starting aid consists of a wire ring (15), the arc tube (1) closer to the lower (14) than on the upper electrode (10) and it with the latter, more distant electrode (10) over connects a series thermal switch (20) and its switching contacts (18) and (19), which are initially closed at room temperature, but after ignition of the arc lamp (1) and open the corresponding temperature rise, so that the starting aid (15) is switched off electrically. 2. A high pressure sodium vapor lamp according to claim 1, characterized in that the gas mixture contains neon and argon. 3. A high pressure sodium vapor lamp according to claim 2, characterized in that the gas mixture contains at least 99% .neon. 509849 / 07U Blank page