DE102015105404A1 - Apparatus and method for determining the concentration or partial pressure of a vapor having magnetic properties - Google Patents

Abstract

The invention relates to a device for determining the magnetic properties of a gas flowing through a flow channel (1), having a primary coil (2) which can be connected to an alternating current generator (9) within the flow channel (1) to produce an alternating magnetic field in the one of the Windings of the primary coil (2) surrounded coil volume and with a connectable to an evaluation secondary coil (3) whose turns also surround the coil volume. Furthermore, the invention relates to a method for determining the concentration or the partial pressure of a vapor or for determining or regulating the flow rate of a vapor having paramagnetic or diamagnetic properties. It is suggested that the coil volume is a torus.

Description

The invention relates to a device for determining the magnetic properties of a flowing through a flow channel formed by a pipe gas, with an arranged within the tube, connectable to an alternator primary coil for generating an alternating magnetic field in the surrounded by the windings of the primary coil coil volume and with a can be connected to an evaluation circuit secondary coil whose turns also surround the coil volume.

The invention also relates to a method for determining the concentration or partial pressure of a vapor or for controlling the flow rate of a vapor having paramagnetic or diamagnetic properties using such a device.

The US 3,076,929 and DE 35 44 966 describe a system for determining the partial pressure or the concentration of a magnetic gas within a measuring cell. The measuring cell is surrounded by a primary coil and a secondary coil, wherein the primary coil generates an alternating current field and the alternating voltage induced in the secondary coil is measured. The measured AC voltage depends on the magnetic properties of the gas in the measuring cell.

From the DE 10 2011 051 931 A1 For example, an apparatus encompassed by the invention is known for depositing OLEDs on a substrate by means of an OVPD method. The substrate is located on a cooled susceptor, on which a vapor phase in a process chamber brought raw material can condense. The transport of the vapor takes place by means of a carrier gas, which is fed into a gas inlet member, which has shower head-like arranged gas outlet nozzles, through which the carrier gas vapor mixture enters the process chamber. The gas inlet member is heated as well as all the upstream gas transport lines to a temperature which is above the condensation temperature of the vapor but below the decomposition temperature of the vapor. The steam generation takes place via an evaporator, which vaporizes a solid or a liquid starting material. The starting material can be introduced as an aerosol into a carrier gas stream. The aerosol is fed into an evaporator body where heat is supplied to the steam so that it changes its state of aggregation into gaseous. Two sensors are used. With a first sensor, which is part of a mass flow controller, the mass of the carrier gas fed into the evaporator is determined. With a second sensor, which is arranged downstream of the evaporator, a sensor signal is generated, which is dependent on the concentration of transported in the carrier gas vapor.

From the DE 10 2010 014 883 A1 . US 2012/203529 A1 . US 2011/304322 A1 . US 7,752,886 B2 . US 7,102,346 B2 . US 6,389,880 B1 . US 6,405,578 B2 . WO 92/07256 A1 . US 5,369,980 A . US 4,988,946 A . US 4,875,357 A . US 4,808,921 A . US 4,563,894 A . US 4,432,226 A Devices are known for determining the concentration of a gas in a measuring cell using the magnetic properties of the gas. In particular, the temperature dependence of the susceptibility of the gas is exploited there.

When used for depositing OLEDs, the carrier gas stream carrying the organic starting materials has a temperature which is in the range between 200 and 450 ° C. The pressure range is in the range of 0.1 to 10 mbar.

The invention has for its object to provide an apparatus and a method, whereby a concentration or partial pressure determination and in particular such is improved in a flowing gas stream.

The object is achieved by the invention specified in the claims, each claim is basically an independent solution to the problem.

First and foremost, it is proposed that the coil volume is a torus. The coil volume surrounding the windings / windings of the secondary coil or primary coil is thus a curved ring. The coil volume forms the measuring cell. It is preferably surrounded on all sides by turns or sections of the turns, free spaces for the passage of the gas from the outside into the coil volume or from the coil volume to the outside being present between the turns. The axis of the torus preferably extends in the direction of extent of the flow channel, that is to say preferably in the direction of flow of the carrier gas flow within a tube which transports the vapor having magnetic properties. The axis of the torus can also extend inclined to the extension direction of the flow channel. It is provided in particular that the axis of the torus is within an imaginary cone with an opening angle of 90 ° about the flow axis, that is inclined at most by an angular amount of 45 ° relative to the flow channel extension direction. But it is also envisaged that the axis of the torus extends transversely to the direction of extension of the flow channel or at a different angle to Extension direction of the flow channel runs. The torus axis can also assume an arbitrary inclination position with respect to the extension direction of the flow channel, for example be angularly offset by an angle between 45 and 90 °. The axis may also coincide with the central axis of a tube forming the flow channel. There are free spaces between the turns of the coil arrangement, so that the gas can enter the coil volume from the outside. The magnetic field is essentially limited to the inner coil volume. The openings between the turns of the coil arrangement are dimensioned such that no dead volumes form within the coil volume. The turns of the primary coil and the turns of the secondary coil are preferably arranged in a uniform circumferential distribution around the torus. However, they are spaced apart such that a gas can pass through the coil volume in the axial direction of the torus. The turns of primary coil and secondary coil are - related to the torus axis - connected to radially inner Windungsabschnitten together. The windings may consist of a metal wire which is ceramic coated. The ceramic coating material may be used to bond the radially inner winding sections together. The radially inner winding sections extend at least partially parallel to the axis of the torus, so that each one of these Windungsabschnitte is connected to a circumferentially adjacent winding section. The joints are formed by a ceramic adhesive. But the windings can also be spaced apart in the radially inner region. Other suitable means may be provided for fixing the turns in a stationary manner. For example, lattice-like ceramic struts may be provided which fix adjacent, spaced-apart turns together. It is essential that the gas can enter the coil volume from the outside and emerge from the inside of the coil volume again. In this respect, it is sufficient if the windings are fixed to each other by non-conductive spacer elements, which need not necessarily be arranged in the radially inner Windungsabschnittsbereich, but may also be provided in the radially outer Windungsabschnittsbereich. Preferably, the turns of primary coil and secondary coil are arranged like a fan. They lie in the circumferential direction alternately next to each other. However, it is also envisaged that the secondary coil has a larger number of turns than the primary coil. Here, too, it is provided that the turns preferably extend only within the toroidal lateral surface and lie next to one another. The coil volume fills more than 50 percent of the cross section of the tube. A coil volume cross-sectional area cut perpendicularly from the torus axis is thus greater than half the cross-sectional area of the tube. Furthermore, it can be provided that the primary coil forms a resonant circuit together with a capacitor. This resonant circuit can be energized by an AC exciter, so that an alternating current flows through the primary coil. This induces an alternating voltage in the secondary coil. The magnitude of the AC voltage is influenced by the magnetic properties of the gas within the coil volume, and therefore the voltage measured at the secondary coil and / or its phase shift to the AC voltage within the primary coil is a measure of the concentration of the vapor within the coil volume. With a second sensor, the flow rate of the carrier gas flow through the tube can be determined, so that the flow rate of the paramagnetic or diamagnetic vapor can be determined from these two measured values. It is also envisaged that the primary coil is heated by passing a current, in particular the alternating current. The gas temperature is between 200 and 450 ° C in a pressure range of 0.1 to 10 mbar. Through heat conduction, in particular through the gas, the secondary coil also heats up. But it is also possible to heat the secondary coil by passing a heating current. The heating currents can be direct currents. The frequency of the alternating current preferably corresponds to the resonance frequency of the primary coil or the secondary coil. Primary coil and / or secondary coil are thus preferably elements of a resonant circuit and are connected in parallel with a capacitor. The device or the method preferably relates to the deposition of OLEDs at temperatures above 300 ° C. It is considered to be particularly advantageous that the magnetic field generated by the primary coil is limited to the interior of the coil volume and the windings are at least partially spaced apart such that a carrier gas carrying a vapor can flow through the coil volume, for which it by two opposing torus Wall sections passes.

An embodiment will be explained below with reference to accompanying drawings. Show it:

1 schematically and partially broken a measuring cell forming tube 1 with a coil arrangement arranged therein 2 . 3 .

2 a plan view of the end face of the flow channel forming tube 1 .

3 a longitudinal section along the line III-III in 2 .

4 the section IV-IV in 2 in a perspective view,

5 a section through the radially inner winding sections 2 ' . 3 ' by means of a ceramic material 6 are connected to each other and

6 an example of a measuring circuit.

The DE 10 2014 101 971 describes a magnetic method for determining a vapor concentration and an apparatus for carrying out this method and in particular an OLED coating device in which a carrier gas is fed into a mass flow controller, which receives a mass flow specification from a control circuit. According to this specification, the mass flow controller provides a constant mass flow of a carrier gas, which is in particular nitrogen. As shown in the local figures and the description, which are made in full content to the disclosure of this application, the carrier gas is supplied via a flow channel to a steam generator. In the steam generator, steam is generated by heating a liquid or a solid. The solid or the liquid is fed from a reservoir into the steam generator. In a flow channel, which connects the steam generator with a coating device, there is a sensor element which is able to determine the concentration of the vapor within the carrier gas-vapor mixture flowing through the flow channel. The measured value is fed to the control circuit, so that by varying the carrier gas flow or the steam generation rate in the steam generator, the steam flow rate through the flow channel into the coating device can be kept at a constant value. To avoid condensation of the vapor on the walls of the flow channel and the sensor element, the carrier gas or the walls of the flow channel is maintained at a temperature which is above the condensation temperature of the vapor. Aromatic hydrocarbons, in particular the precursors for an OLED coating process, are evaporated in the steam generator. This vapor is transported through the flow channel to the coating device. There lie on a cooled substrate holder substrates on the surface of the precursor condense to form an OLED.

That in the 1 to 5 shown sensor element is a coil assembly 2 . 3 , which is able to determine their concentration or their partial pressure in the carrier gas from the magnetic properties of the precursor. The coil assembly has a primary coil 2 and a secondary coil 3 , Both coils 2 . 3 are within the pipe forming the flow channel 1 arranged. The turns of the primary coil 2 and the secondary coil 3 enclose a coil volume which has the shape of a torus. The annular coil volume is arranged around a torus axis A which is coaxial with the axis of the tube 1 runs, so in the flow direction of the gas through the pipe 1 extends.

In the embodiment shown in the figures have primary coil 2 and secondary coil 3 the same number of turns. It is a bifilar coil. The turns of primary coil 2 and secondary coil 3 lie in a common plane, which is the surface of the torus surface. Each coil winding or coil winding has a substantially rectangular cross-section, wherein the corners of the rectangle are rounded. It can be seen from the figures that there is one turn of the primary coil 2 and one turn of the secondary coil 3 alternate in the circumferential direction of the torus. All turns of the coils 2 . 3 lie side by side, so that they form radiating from Torusachse A outgoing turns. The radially inner winding sections 2 ' . 3 ' lie in touching contact together.

The primary coil 2 and the secondary coil 3 are formed by wires which are surrounded by a ceramic jacket. It is an insulation. The primary coil 2 and the secondary coil 3 are thus heatable to temperatures of up to 450 ° C. Heating the primary coil 2 can be done by passing a correspondingly high current. The touching contiguous, linearly parallel to the torus axis A extending radially inner winding sections 2 ' . 3 ' are connected. The compound is in particular of a ceramic adhesive 6 educated. This results in the bobbin, which essentially only from the two air coils 2 . 3 There is the required stability to get inside a pipe 1 to be able to be arranged.

The individual fan-like radially outwardly extending turns of primary coil 2 and the secondary coil 3 are spaced apart such that there is free space between the turns 7 remain, through which the gas can flow in the direction of the torus axis A from the outside into the coil volume and from the inside of the coil volume can flow out again.

The radially outer winding sections 2 '' and 3 '' the primary coil 2 or the secondary coil 3 run parallel to the radially inner Windungsabschnitten 2 ' . 3 ' , The radially inner winding sections 2 ' . 3 ' run in one of the torus axis A perpendicular cut sectional plane on a circle around the torus axis. Also the radially outer winding sections 2 '' . 3 '' are arranged on a circular arc around the center of the torus. The winding cross-section is a rectangle.

The cross-sectional area of the toroidal coil volume is at least half as large as the cross-sectional area of the tube 1 in which is the bobbin 2 . 3 located.

The attachment of the bobbin 2 . 3 inside the tube 1 done by means of the connections 4 . 5 , These are guided through openings of the pipe wall from the inside to the outside, wherein insulating body 12 are provided, with which the connections 4 . 5 opposite the jacket wall of the tube 1 are electrically isolated.

The 5 shows an alternator 9 and a primary coil 2 that with a capacitor 8th is connected to a resonant circuit. As a result, an alternating voltage or an alternating current is generated, the resonant frequency of the resonant circuit 2 . 8th equivalent. The current strength of the alternating current can be so high that with it the primary coil 2 is heated. The heating current can also be a direct current, which is superimposed on the alternating current.

The secondary coil 3 forms with the capacitor 10 a resonant circuit. The in the resonant circuit 3 . 10 induced AC voltage is using an evaluation circuit 11 measured. It is also possible with the evaluation circuit 11 immediately in the secondary coil 3 to measure induced AC voltage. On the capacitor 10 can then be dispensed with. In an embodiment not shown, the number of turns of the primary coil is less than the number of turns of the secondary coil. As a result, a higher voltage is induced in the secondary coil.

The sensor arrangement according to the invention is characterized by a high sensitivity with respect to aromatic hydrocarbon vapors and a low sensitivity to the nitrogen carrier gas. The sensor according to the invention is able to be operated at temperatures up to 450 ° C. He is able to deliver a high data rate. It is operated with response times of less than 100 ms.

The toroidal ring coil assembly has no core. Rather, the steam flowing through the coil volume forms the coupling element with which the primary coil 2 and the secondary coil 3 are magnetically coupled to each other. The windings are interconnected to stabilize the shape of the coil assembly with a zirconium ceramic adhesive material. During operation, in particular, the coils are maintained at a temperature which is above the condensation temperature of the vapor, but below the chemical reaction temperature of the vapor, by passing a heating current. Also the secondary coil 3 can be heated by passing, for example, a direct current. The toroidal arrangement of the coils leads to increased sensitivity. The output voltage of the secondary coil 3 changes with the change in the magnetic properties of the gas within the coil volume. One through the primary coil 2 passing alternating current generates an alternating magnetic field within the coil volume. This alternating magnetic field is influenced by the magnetic properties and in particular the concentration of the magnetic vapor within the coil volume. The alternating magnetic field induces an alternating voltage in the secondary coil 3 , The amplitude of the induced AC voltage is a measure of the magnetic coupling and thus a measure of the concentration of the vapor within the coil volume forming a measuring cell. The reluctance of the magnetic path, and thereby the inductance of the coil or the mutual inductance of the coils, is greatly influenced by the magnetic properties of the gas within the "air" of the two air coils. The ratio of the output voltage of the secondary coil 3 to the input voltage in the primary coil 2 makes it possible to measure the susceptibility of the gas flowing through the sensor. The voltage ratio will increase as the susceptibility of the gas or gas mixture within the coil volume increases.

The two coils can be in a resonance relationship to each other, as it is in the DE 10 2014 101 971 is described. The sensitivity can be optimized by the fact that the AC voltage with which the primary coil is energized, in the vicinity or in the region of the resonance frequency of the primary coil 2 or secondary coil 3 is.

The primary coil 2 can be energized with a variable AC voltage, the coupling ratio of the two coils 2 . 3 depends. But it is also possible, the primary coil 2 to energize with an alternating voltage of constant frequency.

It is considered advantageous that a diamagnetic vapor sensor as described above has little susceptibility to temperature changes and pressure changes. The sensor may also serve as an early warning element to signal when the process parameters are changing. Because the sensor sensitive to oxygen, it can also be used as an oxygen warning element.

The above explanations serve to explain the inventions as a whole, which further develop the state of the art independently, at least by the following feature combinations, namely:
A device characterized in that the coil volume is a torus.

A device which is characterized in that the axis A of the torus at least approximately in the extension direction of the flow channel 1 runs, in particular at most by an angle of 45 ° from the direction of extension of the flow channel 1 differs.

A device characterized in that the turns of the primary coil 2 and the turns of the secondary coil 3 are arranged in a uniform circumferential distribution around the torus.

A device characterized in that the turns of the primary coil 2 and the secondary coil 3 formed coil assembly are spaced apart such that a gas in the axial direction of the torus or in a transverse direction can flow through the coil volume.

A device characterized in that the turns of primary coil 2 and secondary coil 3 are fixed to each other, in particular that the turns with respect to the torus A radially inner winding sections 2 ' . 3 ' have, which are interconnected.

A device, which is characterized in that the radially inner winding sections 2 ' . 3 ' by means of a ceramic material or other fixing means at joints 6 connected to each other.

A device which is characterized in that the turns coated in particular with a ceramic material 2 ' . 3 ' the primary coil 2 and the secondary coil 3 alternately adjacent to each other in the circumferential direction of the torus.

A device characterized in that the secondary coil 3 a larger number of turns 2 ' . 3 ' has as the primary coil 2 ,

A device characterized in that the coil volume cross-sectional area perpendicular to the torus axis A is greater than half the cross-sectional area of the tube 1 ,

A device characterized in that the primary coil 2 together with a capacitor 8th a resonant circuit is formed, which defines the frequency of the alternating current.

A method characterized by using a device according to one or more of the preceding claims.

A method characterized in that the primary coil 2 and / or the secondary coil 3 be heated by passing a current.

A method characterized in that the frequency of the alternating current is approximately the resonance frequency of the primary coil 2 or the secondary coil 3 is.

A method, characterized in that the device is used to stabilize a vapor stream in an apparatus for depositing OLEDs and / or that the device is used as an oxygen warning element and in particular at a temperature above 300 ° C.

All disclosed features are essential to the invention (individually, but also in combination with one another). The disclosure of the associated / attached priority documents (copy of the prior application) is hereby also incorporated in full in the disclosure of the application, also for the purpose of including features of these documents in claims of the present application. The subclaims characterize with their features independent inventive developments of the prior art, in particular to make on the basis of these claims divisional applications.

LIST OF REFERENCE NUMBERS

1

Pipe, flow channel

2

primary coil

2 '

inner winding section

2 ''

outer winding section

3

secondary coil

3 '

turn section

3 ''

outer winding section

4

connection

5

connection

6

Adhesive, joint

7

Freiraum, distance space

8th

capacitor

9

Alternator

10

capacitor

11

evaluation

12

insulator

A

 torus axis

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 3,076,929 [0003]
• DE 3544966 [0003]
• DE 102011051931 A1 [0004]
• DE 102010014883 A1 [0005]
• US 2012/203529 A1 [0005]
• US 2011/304322 Al [0005]
• US 7752886 B2 [0005]
• US 7102346 B2 [0005]
• US 6389880 B1 [0005]
• US 6405578 B2 [0005]
• WO 92/07256 A1 [0005]
• US 5369980 A [0005]
• US 4988946A [0005]
• US 4875357 A [0005]
• US 4808921 A [0005]
• US 4563894 A [0005]
• US 4432226 A [0005]
• DE 102014101971 [0017, 0029]

Claims (15)

Device for determining the magnetic properties of a through a flow channel ( 1 ) flowing gas, with one within the flow channel ( 1 ), with an alternator ( 9 ) connectable primary coil ( 2 ) for generating an alternating magnetic field in which of the turns of the primary coil ( 2 ) surrounded coil volume and with a connectable to an evaluation secondary coil ( 3 ), whose turns also surround the coil volume, characterized in that the coil volume is a torus. Apparatus according to claim 1, characterized in that the axis (A) of the torus at least approximately in the extension direction of the flow channel ( 1 ), in particular at most by an angle of 45 ° from the direction of extent of the flow channel ( 1 ) or that the axis (A) of the torus by an angular amount in the range between 90 ° and 45 ° to the extension direction of the flow channel ( 1 ) is inclined or transversely to the direction of extension of the flow channel ( 1 ) runs. Device according to one of the preceding claims, characterized in that the turns of the primary coil ( 2 ) and the turns of the secondary coil ( 3 ) are arranged in uniform circumferential distribution around the torus. Device according to one of the preceding claims, characterized in that the turns of the primary coil ( 2 ) and the secondary coil ( 3 ) are spaced apart such that a gas in the axial direction of the torus or in a transverse direction can flow through it through the coil volume. Device according to one of the preceding claims, characterized in that the turns of primary coil ( 2 ) and secondary coil ( 3 ) are fixed to each other, in particular that the turns with respect to the torus axis (A) radially inner winding sections ( 2 ' . 3 ' ), which are interconnected. Apparatus according to claim 5, characterized in that the radially inner winding sections ( 2 ' . 3 ' ) by means of a ceramic material or other fixing means at joints ( 6 ) are interconnected. Device according to one of the preceding claims, characterized in that the turns coated in particular with a ceramic material ( 2 ' . 3 ' ) of the primary coil ( 2 ) and the secondary coil ( 3 ) are adjacent to each other in the circumferential direction of the torus. Device according to one of the preceding claims, characterized in that the secondary coil ( 3 ) a larger number of turns ( 2 ' . 3 ' ) than the primary coil ( 2 ). Device according to one of the preceding claims, characterized in that the coil volume cross-sectional area cut perpendicularly from the torus axis (A) is greater than half the cross-sectional area of the tube ( 1 ). Device according to one of the preceding claims, characterized in that the primary coil ( 2 ) together with a capacitor ( 8th ) forms a resonant circuit that defines the frequency of the alternating current. Method for determining the concentration or the partial pressure of a vapor or for determining or regulating the flow rate of a vapor having paramagnetic or diamagnetic properties, characterized by a use of a device according to one or more of the preceding claims. Method according to claim 11, characterized in that the primary coil ( 2 ) and / or the secondary coil ( 3 ) are heated by passing a current. Method according to one of claims 11 or 12, characterized in that the frequency of the alternating current is approximately the resonance frequency of the primary coil ( 2 ) or the secondary coil ( 3 ). Method according to one of claims 11 to 13, characterized in that the device for stabilizing a vapor stream in a device for depositing OLEDs is used and / or that the device is used as an oxygen warning element and in particular at a temperature above 300 ° C. , Apparatus or method characterized by one or more of the characterizing features of any one of the preceding claims.

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