Mds Health Group Limited

Mds Inc.

Business Arts Inc.

Aerospace Engineering and Research Consultants Limited

Bernard Etkin

John Barry French

Raymond Jong

Bjarni V Tryggvason

Guy Legere

Frank J Van Kann

A gravity gradiometer is combined with a two-stage actively controlled isolation system. The gravity gradiometer and two stage isolation system may then be mounted within (or on) a mobile vehicle such as, for example, an aircraft. It has been recognized by the inventors herein that the accelerations imparted to an aircraft during normal operations can be separated through system design into two relatively distinct regimes within the frequency domain. The invention provides a first isolation mount, which forms part of the isolation system, to isolate accelerations (and resulting translations) falling within a first of the two frequency regimes. The second isolation mount, which is mounted to the first isolation mount, isolates accelerations falling within the second of the two frequency regimes. A gravity gradiometer can then be mounted to the second isolation mount. As a result of housing the gravity gradiometer within the nested isolation system (a combination of the first and second isolation mounts), the gravity gradiometer is substantially isolated from the accelerations experienced by the mobile vehicle. Consequently, gravity gradients measured by the gravity gradiometer are relatively noise free and provide heretofore-unobtainable accuracy.

Gravity gradiometry

A spray chamber for producing a sample for an analyzer which may contain a plasma torch. In the chamber, a heated sheath gas is fed into the periphery of the spray surrounding the spray, adjacent the origin of the spray, thus reducing the size of droplets which are recirculated, thereby reducing agglomeration of the droplets and promoting rapid drying of the spray. Preferably all of the spray solvent is evaporated in a very short chamber, thus further reducing the amount of spray recirculated, and all of the combined flow of dried particulates from the spray, nebulizing gas and sheath gas is directed into the torch. In one embodiment, the central core of the combined flow is directed to the torch and the peripheral portion of the combined flow is ducted to waste. In another embodiment the aqueous spray solvent is fully evaporated before it leaves the spray chamber, and the combined flow is directed through a membrane dryer before reaching the torch, to remove most of the water vapor from the flow and thus to reduce water vapor loading on the torch.

Spray chamber with dryer

A torch for Inductively Coupled Plasma Spectrometry (ICPS) is formed from quartz and has inner and outer tubes defining an annular channel. The end of the inner tube is within an end portion of the outer tube, to define a chamber for a plasma ball. An inlet for a main gas flow opens tangentially into the annular channel. The annular channel is configured so as to maximize the swirl component of this flow. To this end, a connection to the inlet is provided with an annular toroidal shape, having a cross-section to or larger than the inlet. Further, the inlet is mounted relatively close to the end of the inner tube, so as to minimise decay of the swirl component as the gas flows along the annular channel, the length of the annular channel being sufficient to ensure that the flow leaving the annular channel is uniform and has a uniform swirl component. This arrangement enables a significantly reduced consumption of gas to generate a plasma ball, and can give improved performance, in terms of a higher detection rate in a spectrometer.

Torch for inductively coupled plasma spectrometry

A liquid sample to be analyzed is fed to a micro pump. The pump directs the solution, as a stream of uniformly sized and spaced droplets, into a laminarly flowing stream of hot carrier gas. The carrier gas evaporates the solvents (e.g. water) in the droplets to form a stream of dried particles. The particles are vaporized by a plasma, laser or other heat source. The vapour can be ionized and the ions analyzed by a mass spectrometer, or the vapour can be analyzed by optical spectroscopy. The method reduces oxide and other interference effects, increases sample utilization, and reduces waste, signal noise, and memory effects, increasing instrument productivity. Multiple nozzles can be used to change samples or to shoot calibrating droplets, further increasing productivity. Signal detection can be synchronized with droplet firing, or the signal, which is intrinsically modulated at the drop frequency, can be band pass filtered and synchronously detected, to increase the signal to noise ratio. The dried particles can also be directed into a vacuum chamber and deposited in a desired pattern on a surface in the vacuum, thus delivering controlled microdosages of material onto the surface.

Apparatus and method for liquid sample introduction

An air curtain fume cabinet, in which an air curtain jet is directed across the face opening to an exhaust duct. Sufficient flow is exhausted at the exhaust duct to swallow (i) the entire air curtain jet, plus (ii) all of the air which the jet entrains from outside the face opening, plus (iii) a substantial additional amount of air. This greatly increases the velocity of air moving into the curtain at its top, beyond the normal entrainment velocity, and prevents spill-back of jet air to the outside even with substantial crosswinds. Preferably the ratio of exhaust flow to jet flow is between 2 and 3 for a jet height to jet thickness ratio of up to about 15. Preferably auxiliary air is supplied to the working space interior to replace air entrained into the jet from inside the working space.

Growing community of inventors

North York, Canada

Bernard Etkin