A method and apparatus (1) for monitoring particles flowing in a stack are disclosed. The method comprises emitting light from a light source along an optical path for scattering from the particles, rotating a rotatable monitoring assembly (15) mounted in the optical path, and detecting the scattered light using a detector. The rotatable monitoring assembly (15) contains at least two in apertures, and the method further comprises rotating the rotatable monitoring assembly (15) into a plurality of different configurations. In an operation configuration, light passes through the rotatable monitoring assembly (15) and into the stack unimpeded. In a zero-check configuration, the rotatable monitoring assembly (15) blocks the light from reaching the stack. In a span-check configuration, light of varying intensity passes from the light source through the rotatable monitoring assembly (15) into the stack. In a contamination-check configuration, the light is reflected through the rotatable monitoring assembly (15) onto the detector, without entering the stack. In the safety-shutter configuration, the rotatable monitoring assembly (15) protects optical components in the instrument from particles in the stack.

A wood stove monitoring and control device can include a mounting flange mountable to a chimney exhaust pipe of a wood stove. The device can include a ring removably mountable on top of the mounting flange, where the flange is suitably positioned vertically along the exhaust pipe so that the ring is positioned at least partially above an end of the exhaust pipe. The device includes an optical beam source disposed on the ring, and which generates and outputs an optical beam. The device includes an optical sensor positioned on the ring opposite the optical beam source to detect the optical beam output by the optical beam source as the optical beam passes through smoke exhausted by the wood stove through the exhaust pipe. The device can include a temperature probe disposed on the ring to measure a temperature of heat exhausted by the wood stove through the exhaust pipe.

An apparatus for optical in-situ gas analysis includes: a housing; a measuring lance a first end connected to the housing and a second end projecting into the gas to be measured; a light transmitter that is arranged in the housing and whose light is conducted into the measuring lance and is reflected by a reflector arranged at the second end onto a light receiver, and the optical path defines an optical measurement path within the measuring lance; and, an evaluation device for evaluating received light signals of the light receiver. In order to be able to reduce the consumption of test gas, the measuring lance has an outer tube, with the outer tube having openings for the gas to be measured. The openings can be closed by at least one seal for the test phase, with the seal searingly closing the openings by the enlargement of its volume.

A laser gas analyzer includes a light emitter which emits a laser light irradiated onto a gas to be measured; a light receiver which receives a laser light which transmitted the gas to be measured; a plurality of optical-axis adjustment mechanisms, one of which is provided in the light emitter and the other one of which is provided in the light receiver; a main display which is provided in one of the light emitter and the light receiver and displays thereon the measured result acquired by receiving the laser light which transmitted the gas to be measured; and a sub-display which is provided in the other one of the light emitter and the light receiver and displays thereon a part of the measured result displayed on the main display.

A wood stove monitoring and control device can include a mounting flange mountable to a chimney exhaust pipe of a wood stove. The device can include a ring removably mountable on top of the mounting flange, where the flange is suitably positioned vertically along the exhaust pipe so that the ring is positioned at least partially above an end of the exhaust pipe. The device includes an optical beam source disposed on the ring, and which generates and outputs an optical beam. The device includes an optical sensor positioned on the ring opposite the optical beam source to detect the optical beam output by the optical beam source as the optical beam passes through smoke exhausted by the wood stove through the exhaust pipe. The device can include a temperature probe disposed on the ring to measure a temperature of heat exhausted by the wood stove through the exhaust pipe.

A wood stove monitoring and control device can include a mounting flange mountable to a chimney exhaust pipe of a wood stove. The device can include a ring removably mountable on top of the mounting flange, where the flange is suitably positioned vertically along the exhaust pipe so that the ring is positioned at least partially above an end of the exhaust pipe. The device includes an optical beam source disposed on the ring, and which generates and outputs an optical beam. The device includes an optical sensor positioned on the ring opposite the optical beam source to detect the optical beam output by the optical beam source as the optical beam passes through smoke exhausted by the wood stove through the exhaust pipe. The device can include a temperature probe disposed on the ring to measure a temperature of heat exhausted by the wood stove through the exhaust pipe.

A wood stove monitoring and control device can include a mounting flange mountable to a chimney exhaust pipe of a wood stove. The device can include a ring removably mountable on top of the mounting flange, where the flange is suitably positioned vertically along the exhaust pipe so that the ring is positioned at least partially above an end of the exhaust pipe. The device includes an optical beam source disposed on the ring, and which generates and outputs an optical beam. The device includes an optical sensor positioned on the ring opposite the optical beam source to detect the optical beam output by the optical beam source as the optical beam passes through smoke exhausted by the wood stove through the exhaust pipe. The device can include a temperature probe disposed on the ring to measure a temperature of heat exhausted by the wood stove through the exhaust pipe.

A wood stove monitoring and control device can include a mounting flange mountable to a chimney exhaust pipe of a wood stove. The device can include a ring removably mountable on top of the mounting flange, where the flange is suitably positioned vertically along the exhaust pipe so that the ring is positioned at least partially above an end of the exhaust pipe. The device includes an optical beam source disposed on the ring, and which generates and outputs an optical beam. The device includes an optical sensor positioned on the ring opposite the optical beam source to detect the optical beam output by the optical beam source as the optical beam passes through smoke exhausted by the wood stove through the exhaust pipe. The device can include a temperature probe disposed on the ring to measure a temperature of heat exhausted by the wood stove through the exhaust pipe.

An exhaust detecting safety switch assembly for turning off an oil burner when a disruptive quantity of exhaust is detected includes an oil burner. The oil burner ignites oil to define a flame when the oil burner is turned on. An ignition is positioned in and is in electrical communication with the oil burner. The ignition is actuated to ignite the oil. A shutoff is electrically coupled to the ignition and is actuated to turn the oil burner off when the shutoff no longer detects the flame. A safeguard unit is mounted on and is in fluid communication with the oil burner. The safeguard unit is electrically coupled to the ignition. The safeguard unit detects when the oil burner emits a disruptive quantity of opaque exhaust and when detected turns the oil burner off. The safeguard unit is positioned to inhibit access to the safeguard unit.

A method and apparatus (1) for monitoring particles flowing in a stack are disclosed. The method comprises emitting light from a light source along an optical path for scattering from the particles, rotating a rotatable monitoring assembly (15) mounted in the optical path, and detecting the scattered light using a detector. The rotatable monitoring assembly (15) contains at least two in apertures, and the method further comprises rotating the rotatable monitoring assembly (15) into a plurality of different configurations. In an operation configuration, light passes through the rotatable monitoring assembly (15) and into the stack unimpeded. In a zero-check configuration, the rotatable monitoring assembly (15) blocks the light from reaching the stack. In a span-check configuration, light of varying intensity passes from the light source through the rotatable monitoring assembly (15) into the stack. In a contamination-check configuration, the light is reflected through the rotatable monitoring assembly (15) onto the detector, without entering the stack. In the safety-shutter configuration, the rotatable monitoring assembly (15) protects optical components in the instrument from particles in the stack.