Method and apparatus for detecting particles in a flow
First Claim
1. A method of detecting particles flowing along a emitted through the stack in which a probe is positioned so that it projects into the flow of particles and is charged by the particles in the flow characterized in that the part of the probe that projects into the particle flow comprises an electrically conducting core covered with an insulating layer which insulates the core from the particle flow and the A.C. component of a signal from the probe is evaluated to provide an indication of the particle flow.
2 Assignments
0 Petitions
Accused Products
Abstract
An apparatus for detecting particles in a flow comprises a probe 1 positioned so that it projects into the flow and is charged triboelectrically by the particles in the flow. An electric circuit is coupled to the probe 1 and includes evaluating means for monitoring a signal from the probe 1 and for providing an output in dependence on the signal generated by the triboelectric charging of the probe 1. The part of the probe 1 that projects into the particle flow comprises an electrically conducting core covered with an insulating layer 2 which insulates the core from the particle flow.
49 Citations
34 Claims
- 1. A method of detecting particles flowing along a emitted through the stack in which a probe is positioned so that it projects into the flow of particles and is charged by the particles in the flow characterized in that the part of the probe that projects into the particle flow comprises an electrically conducting core covered with an insulating layer which insulates the core from the particle flow and the A.C. component of a signal from the probe is evaluated to provide an indication of the particle flow.
- 8. Apparatus for detecting particles flowing along a stack and emitted through the stack comprising a probe to be positioned so that it projects into the flow to be charged by the particles in the flow, and an electric circuit coupled to the probe characterized in that the part of the probe to project into the particle flow comprises an electrically conducting core covered with an insulating layer which insulates the core from the particle flow, and the electric circuit has evaluating means for monitoring an A.C. component of the signal from the probe for providing an output in dependence on the signal generated by the triboelectric charging of the probe.
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15. A method of detecting particles flowing along a stack and emitted through the stack in which a probe is positioned so that it projects into the flow of particles and is charged by the particles in the flow characterized in that the part of the probe that projects into the particle flow comprises an electrically conducting core covered with an insulating layer which insulates the core from the particle flow, the signal from the probe is filtered to block the D.C. signal and the A.C. signal is evaluated to provide an indication of the particle flow.
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16. Apparatus for detecting particles flowing along a stack and emitted through the stack comprising a probe to be positioned so that it projects into the flow to be charged by the particles in the flow, and an electric circuit coupled to the probe characterized in that the part of the probe to project into the particle flow comprises an electrically conducting core covered with an insulating layer which insulates the core from the particle flow, and the electric circuit has filter means for blocking the D.C. signal from the probe an evaluating means for monitoring the filtered A.C. signal for providing an output in dependence on the signal generated by the triboelectric charging of the probe.
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17. A method of detecting particles flowing along a stack and emitted through the stack in which a probe is positioned so that it projects into the flow of particles and is charged by the particles in the flow characterized in that the part of the probe that projects into the particle flow comprises an electrically conducting core covered with an insulating layer which insulates the core from the particle flow, that the signal from the probe is filtered to limit the signal to an A.C. signal of frequency above about 0.1 Hz and the A.C. signal is evaluated to provide an indication of the particle flow.
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18. Apparatus for detecting particles flowing along a stack and emitted through the stack comprising a probe to be positioned so that it projects into the flow to be charged by the particles in the flow, and an electric circuit coupled to the probe characterized in that the part of the probe to project into the particle flow comprises an electrically conducting core covered with an insulating layer which insulates the core from the particle flow, and the electric circuit has filter means for limiting the signal from the probe to an A.C. signal of frequency above about 0.1 Hz and evaluating means for monitoring the filtered A.C. signal for providing an output in dependence on the signal generated by the triboelectric charging of the probe.
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19. A method of detecting particles flowing along a stack and emitted through the stack in which a probe is positioned so that it projects into the flow of particles and is charged by the particles in the flow characterised in that the part of the probe that projects into the particle flow comprises an electrically conducting core covered with an insulating layer which insulates the core from the particle flow and a signal from the probe is filtered to exclude frequency components below about 0.1 Hz and above about 5 Hz and is evaluated to provide an indication of the particle flow.
- 20. A method of detecting particles flowing along a stack and emitted through the stack in which a probe is positioned so that it projects into the flow of particles and is charged by the particles in the flow characterised in that the part of the probe that projects into the particle flow comprises an electrically conducting core covered with an insulating layer which insulates the core from the particle flow, the insulating layer being substantially thinner than the conducting core, and a signal from the probe is evaluated to provide an indication of particle flow.
- 23. A method of detecting particles flowing along a stack and emitted through the stack in which a probe is positioned so that it projects into the flow of particles and is charged by the particles in the flow characterised in that the part of the probe that projects into the particle flow comprises an electrically conducting core covered with an insulating layer which insulates the core from the particle flow and the probe generates a current signal which is converted into a voltage signal, said voltage signal being passed through signal processing means which block the DC component of the voltage signal to generate a processed voltage signal, and, said processed voltage signal being subsequently evaluated to provide an indication of the particle flow.
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25. Apparatus for detecting particles suspended in a gas flow flowing along a gas flow path emitted through a sack, the apparatus comprising:
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a probe projecting into the gas flow path for detecting particles in the gas flow along the stack, a wall defining a boundary of the gas flow path, the probe comprising an electrically conducting core and a covering layer, the covering layer being electrically insulating and serving to block conduction of a DC current from the surface of the probe through the insulating layer to the electrically conducting core of the probe, the probe being fixed in the wall with the electrically conducting core electrically insulated from the wall, and an electric circuit connected to the electrically conducting core of the probe for evaluating the signal from the core of the probe for providing an output in dependence on the signal generated by the charging of the probe. - View Dependent Claims (26, 27, 28, 29, 30, 31)
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- 32. A method for detecting particles flowing in a gas flow along a stack and emitted through the stack in which a probe including a portion which comprises an electrically conducting core covered by an insulating layer which insulates the core from particle flow is positioned so that said portion projects into the flow of particles in the stack and is charged triboelectrically by particles in the flow and the quantities of electrical charges transferred to the probe are evaluated to provide an indication of the particle flow in the gas flow, wherein, in order to reduce the effect of variations in gas flow related variables other than those relating to particle flow, an alternating component in the signal caused by the triboelectrical charging of the probe is monitored, the alternating component of the signal from the probe is filtered to exclude high frequency components of the signal and the magnitude of the residual alternating component is itself used to give an indication of the particle flow through the stack.
Specification