MXPA01008070A - A coriolis flowmeter having an explosion proof housing - Google Patents

Abstract

A system enclosing a Coriolis flowmeter in a explosion proof housing. The explosion proof housing is structured in a way that the housing can withstand an explosion of volatile material inside the housing. The explosion proof housing prevents sparks and heat inside the housing from igniting volatile material outside the housing. Any gaps or openings in the explosion proof housing provide a flame path of sufficient length to cool a flame or hot material escaping from the housing. The use of the secondary housing as an explosion proof compartment allows the use of a driver having greater power as well as conventional leads inside the housing.

Description

FLUJOME RO DE CORIOLIS WHICH HAS AN EXPLOSION PROOF ACCOMMODATION FIELD OF THE INVENTION This invention relates to a Coriolis flow meter. More particularly, this invention relates to an intrinsically safe Coriolis flow meter. Even more particularly, the present invention relates to the use of a secondary containment housing to create a Coriolis flow meter that meets intrinsic safety requirements.

BACKGROUND OF THE INVENTION Problem It is known to use Coriolis mass flow meters to measure the mass flow and other information of materials flowing through a pipe such as those described in the U.S. patent. No. 4,491,025 issued to J.E. Smith, et al. , on January 1, 1985 and Re. 31,450 to J.E. Smith, February 1982. These flow meters have one or more flow tubes of a curved configuration. Each REF: 131789 configuration of the flow tube in a Coriolis mass flowmeter has a set of natural vibration modes, which can be of a simple type of bending, torsional, radial or coupled. Each flow tube is driven to oscillate in resonance in one of these natural modes. The natural vibration modes of systems filled with materials and vibrators are defined in part by the combined mass of the flow tubes and material within the flow tubes. The material flows inside the flow meter from a connected pipe on the input side of the flow meter. The material is then directed through the flow tube or flow tubes and out of the flow meter into a pipe connected on the outlet side. An exciter applies a vibratory force to the flow tube. The force causes the flow tube to oscillate. When there is no material flowing through the flowmeter, all points along a flow tube oscillate with an identical phase. As a material begins to flow through the flow tube, the Coriolis accelerations cause each point along the flow tube to have a different phase with respect to the other points along the flow tube. The phase on the inlet side of the flow tube is located behind the exciter, while the phase on the side. output is in front of the exciter. Sensors are placed at two different points on the flow tube to produce sinusoidal signals that represent the movement of the flow tube at the two points. A phase difference of the two signals received from the sensors is calculated in units of time. The phase difference between the two sensor signals is proportional to the mass flow velocity of the material flowing through the flow tube or flow tubes. It is a problem to create an explosion-proof Coriolis flowmeter for use in an explosive environment. In particular, it is a problem to create an explosion-proof Coriolis flow meter for a large Coriolis flow meter. For the purposes of the present description, large Coriolis flow meters have flow tubes with a diameter of more than one inch (2.54 cm) and operate at a resonant frequency of more than one hundred hertz. Also for the purposes of the present description, an explosive environment is a system that includes a volatile material that can be ignited if a spark or excessive heat is introduced into the environment. In addition, an explosion-proof device, such as a Coriolis flowmeter, is a device that is designed to ensure that a spark or excessive heat coming from the device does not ignite the volatile material in the environment. To provide an explosion-proof device, such as a Coriolis flowmeter, methods including encapsulation, pressurization and flame-proof containment may be used. Each of the above methods includes a device for preventing the volatile material from contacting the device when the hot surfaces of the device or sparks coming from the circuitry could cause ignition of the material, such as the explosion-proof housing. described in DE 38 42 379 A issued to Josef Heinrichs Meßgerátebau GMBH & amp;; Co. If a material is ignited within a housing, any space or opening in the housing must provide a flame path of sufficient length to cool the material while it escapes from the housing. The cooling of the hot material prevents it from igniting the volatile material outside the housing. A second solution is to make an intrinsically safe device. An intrinsically safe device is a device in which all the circuitry of the device operates at a certain low energy level. Operating at a certain energy level ensures that the device does not generate a spark or sufficient heat to cause an explosion even if the device fails in some way. The level of energy needed to make an intrinsically safe device is determined by regulatory agencies such as UL in the United States, CENELEC in Europe, CSA in Canada and TUS in Japan. However, the energy requirements for vibrating flow tubes in a large Coriolis flowmeter make it very difficult to design a Coriolis flow meter that is intrinsically safe as shown in the U.S. patent. No. 5,400,653 issued to Kalotay and assigned to Micro Motion, Inc. One way in which flowmeters have been made explosion-proof is to enclose the components of the electronic excitation system mounted on the flow tubes operating on them. intrinsically safe energy levels. A conventional excitation system has a coil and a magnet that are mounted on the flow tubes opposite each other. An alternating current is then applied to the coil, which causes the magnet and the coil to move in opposition to each other. The current applied to the coil is above the levels required for the excitation system to be intrinsically safe. Therefore, it is possible that the current through the coil has enough energy to create a spark or enough heat to ignite volatile materials. To make the excitation coil explosion-proof, a sleeve is placed around the coil. The sleeve is a housing that surrounds the wire coil and may contain an explosion caused by a spark or heat coming from the coil. Any space in the sleeve is designed to have a flame path of sufficient length to cool any material that is ignited within the housing. This prevents any material ignited inside the housing from igniting the material outside the housing. In order for the sleeve and coil to be able to withstand the pressure caused by an explosion, both the sleeve and the coil must be made of metal. This is a problem because metals cause eddies when the magnetic field is subjected to the metal. The eddies are caused by alternating magnetic fields through the conductive medium of the metal sleeve and coil. These eddies cause a reduction in the energy available to excite the flow tubes. The energy is lost because the eddies can be so large that it is impossible to create an excitation that has sufficient power to excite the flow tubes of a certain mass, stiffness or frequency. Moreover, the cost of components for the exciter increases with the use of more expensive metal components. In addition, the conductors connecting the exciter and sensors to the electronic components of the flowmeter must also be isolated to prevent a spark from a conductor due to a break in the conductor causing an explosion so that a flow meter can be proof of Explosions A way to isolate the conductors in that of placing a conduit of encapsulated material over the flow tubes. The conductors are enclosed within the encapsulated conduit. However, this conduit encapsulated over the flow tubes can cause a problem of cerop stability in the flow meter. Moreover, the encapsulated conduit is expensive and time-consuming to manufacture.

For the above reasons, there is a need in the art for Cox olis flowmeters in a better way in which to make a Coriolis flow meter that can operate in an explosive environment while operating at energy levels above intrinsically safe limits.

Solution The above and other problems are solved and an advance in the art is made by the provision of a secondary containment for a Coriolis flowmeter sensor which is also an explosion-proof container. A secondary containment encloses the flow tubes of the flowmeter, as well as the exciter, sensors and conductors attached to the flow tubes. A secondary explosion-proof housing is a secondary containment housing that is made of a material that is capable of withstanding the pressure generated by an explosion caused by an ignition of volatile materials within the housing. Any spaces or openings in an explosion-proof housing provide a flame path that is of sufficient length to cool any flame or heated material that may escape from the housing. The use of a secondary containment such as an explosion-proof enclosure allows the removal of wraps around the coil in the excitation system. In this way, the exciters can be made from less expensive materials and can operate at higher energy levels to provide more energy to oscillate the flow tubes. Furthermore, the conductors inside the housing also do not have to be wrapped in an encapsulated conduit over the flow tubes, which improves the zero stability of the flowmeter sensor. In order to withstand the pressure resulting from an explosion, the secondary housing design has been modified to allow the housing to withstand the pressure of an explosion. The housing is formed to wrap the flow tubes of a flowmeter inside a sealed compartment. The housing has an entry base plate near an inlet side of the flow tubes and a base plate near an outlet end of the flow tubes. The entry and exit base plates are platforms that are formed to allow the flow tubes to extend through the plates and form the end walls that enclose the opposite ends of the flow tubes. In a preferred embodiment, the input and output base plates are part of the inflow and outflow manifolds of the flowmeter. Between the first end and the second end of the housing, the walls of the housing form a U-shaped fold defining an arch. The arc in the wall of the housing distributes the pressure of an explosion over the entire arc and reduces the number of weak points, such as junctions, in the housing that are susceptible to rupture by the pressure of an explosion. The explosion-proof housing must also have at least one opening to allow conductors to pass through the housing to connect the exciter and sensors within the housing with electronic measuring components outside the housing. The opening should provide a flame path of sufficient length to cool any hot gas or flame that escapes through the opening in an explosion. One solution is to encapsulate the conductors inside the housing side to reduce the flame path to the conductors passing through the housing. To encapsulate the conductors within the housing, a step capacitor capacitor is used in the preferred embodiment. In the present invention, the capacitor step capacitor is an element made of a material that can withstand an explosion. The conductors are encapsulated in an opening through the pass capacitor capacitor. The encapsulated material prevents an explosion from escaping through the pass capacitor capacitor and reduces the flame path to the length of each conductor passing through the capacitor pass capacitor. The step capacitor capacitor then fits into an opening in the housing and is welded or otherwise fixed in place in an opening through the housing.

One aspect of this invention is a Coriolis flowmeter having at least one flow tube which is substantially U-shaped, an excitation system attached to said at least one flow tube for vibrating said at least one tube. of flow, sensors attached to said at least one flow tube to measure the oscillations of said at least one flow tube in response to said excitation system by vibrating said at least one flow tube and to transmit information about said flow tube. said oscillations to electronic measuring components, an input manifold fixed to an input end of said at least one flow tube, wherein the input manifold directs a flow of material into said at least one flow tube, an outlet manifold fixed to an outlet end of said at least one flow tube for directing said material flow which from said at least one flow tube into a pipeline connects gives; The flowmeter is characterized by: an explosion-proof housing enclosing said at least one flow tube, said excitation system and said sensors, wherein the explosion-proof housing is adapted to contain an explosion of volatile material ignited within of said explosion-proof housing and preventing sparks and high temperatures within said explosion-proof housing from igniting volatile materials outside said housing, and wherein said explosion-proof housing has a first end attached to said input manifold and a second end attached to said output manifold for enclosing said at least one flow tube in said housing, further comprising: a substantially U-shaped bend between said first end and said second end of said explosion-proof housing, wherein said substantially U-shaped fold is defined as an arc between said first ex and said second end of said explosion-proof housing for distributing the voltage applied to said explosion-proof housing on said arc. Another aspect is a first conductor having a first end connected to said excitation system within said explosion-proof housing and having a second end connected to electronic measurement components outside said explosion-proof housing; at least one opening in said explosion-proof housing through which said first conductor passes from within said explosion-proof housing to the outside of said explosion-proof housing; and a flame path including said first conductor through said opening, wherein the flow path has a length sufficient to cool hot volatile materials that escape through said path.

Another aspect is second conductors having a first end connected to said sensors inside said explosion-proof housing and a second end connected to said electronic measurement components for transmitting signals from said sensors to said electronic measurement components, wherein said second conductors pass from the inside of said explosion-proof housing to the outside of said explosion-proof housing through said at least one opening and wherein each of said second conductors defines a flame path having a sufficient length as to cool a hot volatile material that escapes. Another aspect is that said at least one flow tube includes a first flow tube and a second flow tube, and said input manifold comprises: an entry opening for receiving a flow of material coming from a pipe; a first outlet providing a first flow from said inlet opening to said first flow tube; a second outlet providing a second flow from said inlet opening to said second flow tube; and a divider near said inlet opening that divides said flow coming from said inlet opening in said first flow and said second flow, wherein the divider is close to said inlet opening to minimize the volume in a flow path within of said output manifold from said inlet opening to reduce the eddies in said flow. Another aspect is that said explosion-proof housing is divided into a first middle section and a second middle section divided along a longitudinal axis between said first end and said second end of said explosion-proof housing, wherein said first The middle section and said second middle section are joined to each other and said inlet manifold and said outlet manifold at the time of assembly to enclose said at least one flow tube. Another aspect is that said input manifold comprises: a first molten plate of said input manifold having a first surface; at least one outlet opening of the manifold on said first surface of said first molten plate connecting said inlet manifold to said at least one flow tube; and said first end of said explosion-proof housing is attached to said first surface of said first molten plate. Another aspect is that said output manifold comprises: a second molten plate of said output manifold having a first surface; at least one entry aperture of the manifold on said first surface of said second molten plate connecting said output manifold to said at least one flow tube; and said second end of said explosion-proof housing is attached to said first surface of said second molten plate to enclose said at least one flow tube.

DESCRIPTION OF THE DRAWINGS The foregoing and other features of a Coriolis flowmeter having an explosion-proof housing are described below in the detailed description and in the following drawings: Figure 1 illustrates a Coriolis flow meter of the present invention; Figure 2 illustrates an explosion-proof housing attached to a Coriolis flow meter; Figure 3 illustrates an exploded view of a Coriolis flow meter enclosed in an explosion-proof housing; Figure 4 illustrates a cross-sectional view of a Coriolis flow meter housed in an explosion-proof housing; Figure 5 illustrates an exemplary embodiment of a manifold for a Coriolis flowmeter having an explosion-proof housing; Figure 6 illustrates a cross-sectional view of a flow path through the exemplary manifold along line 6 of Figure 5; Figure 7 illustrates an exemplary embodiment of a pass capacitor capacitor for an explosion-proof housing; Figure 8 illustrates a cross sectional view of the exemplary step capacitor capacitor along line B; Figure 9 illustrates an exciter of a Coriolis flow meter; Figure 10 illustrates a section of the housing having a rib; Figure 11 illustrates a cross-sectional view of a conventional coil; and Figure 12 illustrates a cross-sectional view of an alternative coil.

DETAILED DESCRIPTION OF THE INVENTION General Coriolis Flowmeter - Fig. 1 Figure 1 illustrates a Coriolis flowmeter 5 comprising a flowmeter assembly 10 and electronic measurement component 20. The electronic measurement component 20 is connected to the measurement assembly 10 by means of cables 100 to provide density, mass flow rate, volume flow rate, total mass flow, temperature and other information on the path 26. It should be apparent to those skilled in the art that the present invention can be used by any type of Coriolis flowmeter regardless of the number of exciters, the number of selective sensors, the operational vibration mode. The flow meter assembly 10 includes a pair of flanges 101 and 101 '; multiple 102 and 102 '; exciter 104; selective sensors 105-105 '; and flow tubes 103A and 103B. The exciter 104 and selective sensors 105 and 105 'are connected to flow tubes 103A and 103B. The flanges 101 and 101 'are fixed to multiple 102 and 102'. The manifolds 102 and 102 'are connected to opposite sides of the separator 106. the spacer 106 maintains the spacing between the manifolds 102 and 102' to avoid unpleasant vibrations in the flow tubes 103A and 103B. When the flow meter assembly 10 is inserted into a pipe system (not shown) carrying the material being measured, the material enters the flow meter assembly 10 through the flange 101, passes through the input manifold 102 where the total amount of material is directed to enter the flow tubes 103A and 103B, flows through the flow tubes 103A and 103B and back into the outlet manifold 102 'where it exits the measurement assembly 10 through of the rim 101 '. The flow tubes 103A and 103B are suitably selected and mounted to the input manifold 102 and output manifold 102 'to have substantially the same distribution of mass, moments of inertia and elastic moduli on bending axes WW and W' -W 'respectively . The flow tubes extend outwardly from the manifolds in an essentially parallel fashion. The flow tubes 103A-B are excited by the driver 104 in opposite directions on their respective bending axes W and W 'and in what is called the first output of the bend mode of the flow meter. The exciter 104 may comprise one of many well-known arrangements, such as a magnet mounted to the flow tube 103A and an opposing spool mounted to the flow tube 103B. An alternating current is passed through the opposing coil to cause both tubes to oscillate. A suitable excitation signal is applied by the electronic measurement component 20 via the cable 110 to the exciter 104. The description of Figure 1 is simply provided as an example of the operation of a Coriolis flowmeter and is not intended to limit the teaching of the present invention. The electronic measuring component 20 receives the right and left speed signals appearing on the cables 111 and 111 ', respectively. The electronic measurement component 20 produces the excitation signal on the cable 110, which causes the exciter 104 to oscillate the flow tubes 103A and 103B. The present invention as described herein, can produce multiple excitation signals for multiple exciters. The electronic measurement component 20 processes the left and right speed signals to calculate the mass flow rate. The path 26 provides an input means and an output means that allows the electronic measurement component 20 to establish an interface with an operator. An explanation of the circuitry of the electronic measurement component 20 is unnecessary to understand the explosion-proof housing of the present invention and is omitted for brevity to this description.

An Explosion-Proof Housing - Fig. 2 Fig. 2 illustrates an explosion-proof housing 200 enclosing the flow tubes 103A and 103B of the Coriolis 5 flowmeter. It is conventional for a Coriolis flowmeter to have a secondary containment housing that enclose the flow tubes 103A and 103B (shown in Figure 1) to prevent material from escaping in case one or both of the flow tubes 103A and 103B are broken. In the present invention, an explosion-proof housing 200 that can withstand an explosion of volatile materials contained within the housing 200 encloses the flow tubes 103A and 103B, the driver 104 and the sensors 105-105 '(see Figure 3). The explosion-proof housing 200 also prevents sparks and high temperatures generated by the components of the flowmeter assembly 10 from igniting the volatile materials outside the housing 200. For the purposes of the present disclosure, the volatile material is any gas, liquid or solid which can be ignited by a spark or by the application of heat. To withstand an explosion, the housing 200 must be stronger than a conventional secondary containment housing in order to withstand the pressure generated by an explosion of volatile material in the housing 200 caused by a spark coming from an electronic component. The electronic components within the housing 200 may include but are not limited to the exciter 104, the sensors 105-105 'and wires 110, lililí' (see Figure 3). By providing an explosion-proof housing 200, the driver 104 (shown in detail in Figure 9) does not have to include a housing for the coil. The housing is typically a metal sleeve that is placed around a coil and the coil wires. The metal sleeve typically causes eddies in the magnetic fields of the exciter, which reduces the power of the exciter. Since the metal sleeve is not needed in the explosion-proof housing 200, a more powerful exciter could be used in the Coriolis 5 flowmeter and flow tubes capable of having higher flow rates can be produced. Another advantage of having an explosion-proof housing 200 is that an encapsulated conduit does not have to be adhered to the flow tubes 103A and 103B. The encapsulated conduit is an insulated material that encloses the cables 110, 111 and 111 'to prevent cables from igniting the atmosphere inside the housing, causing an explosion. The encapsulated conduit can cause in zero stability problem for the flow tubes 103A and 103B. The elimination of the encapsulated conduit eliminates the problem of zero stability caused by the conduit. One way in which the housing 200 can be reinforced to withstand an explosion within the housing 200 is to use an arc 203 in the curvature of the housing 200. A typical secondary containment housing is made of several separate pieces that are welded together at angulated points to form the fold in the housing. Each joint is a point at which sufficient pressure from an explosion could tear sections of the housing. The arch 203 distributes any pressure applied to the housing through the surface of the arch and reduces the joints in the housing that could be released by the pressure generated by an explosion.

An Exploded View of a Coriolis Flowmeter in an Explosion-Proof Housing - Fig. 3 Figure 3 illustrates an exploded view of an exemplary embodiment of a Coriolis flow meter 5 within an explosion-proof housing 200. The housing under test of explosions has a first end and a second end that enclose the flow tubes 103A and 103B. In the preferred exemplary embodiment, the first end is a molten plate 303 that is fixed to the manifold 102 on the inflow side of the flowmeter 5 and the second end is a fused plate 304 that is attached to the manifold 102 '. Those skilled in the art will recognize that although a specific design is described for an explosion-proof housing, there are several methods that can be used to enclose the flow tubes. For example, one skilled in the art will recognize that the base of the explosion-proof housing 200 may or may not be fixed to the input and output manifolds 102-102 '. In a preferred embodiment, the molten plate 303 and the molten plate 304 are melted as part of the manifolds 102 and 102 '. However, one skilled in the art will note that the molten plates 303 and 304 can also be fixed to the manifolds 102 and 102 'by welding or other methods. The housing 200 also has a first middle section 301 and a second middle section 302 which are the first and second sides of the housing 200. The first middle section 301 and the second middle section 302 are sections of curved walls between a first edge 390 and a second. second edge 391 to form a cylindrical housing when the two middle sections are joined. The first middle section 301 and the second middle section 302 are also bent into a substantially U-shaped shape between a first end 393 and a second end 394 to coincide with the bends of the flow tubes 103A and 103B. Figure 10 illustrates a portion of an outer circumference of a middle section having a rib 1010. The ribs 1010 are raised on the outer surface of a middle section 301 or 302 of the housing. The ribs 1010 can act as a support element in each middle section 301 or 302 of the housing. It should be noted that a middle section such as the middle section 301 or 302 can have any number of ribs 1010 on the outer circumference of the middle section. To facilitate the joining of the first middle section 301 and the second middle section 302, one section may have a projection 1001 (figure 10) along each edge of a first middle section 301 and the other middle section 302 of the housing 200 may having a slot (not shown) along each edge to receive a matching projection from the edges of the first middle section. As shown in Figure 3, the first middle section 301 and the second middle section 302 are coupled around the flow tubes 103A and 103B and welded together or fixed in some other way. A first end of the first middle section 301 and the second middle section 302 is welded or in some other way fixed to the molten plate 303 at the moment in which the two sections are joined together. A second end of the first middle section 301 and the second middle section 302 is also welded or in some other way attached to the molten plate 304 to enclose the flow tubes 103A and 103B, exciters 104 and sensors 105-105 'within the housing 200. The conductors 110, 111 and 111 'pass through the opening 308 (not seen in figure 3) and the opening 309 to connect the exciter 104 and the sensors 105-105' to the electronic measurement component 20. The openings 306 (not shown in Figure 3) and 307 should provide a flow path that is narrow and of sufficient length to cool a volatile material heated or ignited. To reduce the opening to the width of the conductors, the conductors 110-111 'are typically encapsulated in the wall of the housing 200. One way to minimize the opening to the conductors is the use of a capacitor capacitor pitch. In the preferred embodiment, the step capacitors 308 and 309 are devices that fit into openings 306 and 307 to prevent an explosion from escaping through the openings 308 and 309 in the explosion-proof housing 200. Capacitor capacitors 308 (not shown in Figure 3) and 309 allow wires 110, 111 and 111 'to pass through openings 306 and 307. Although openings 306 and 307 are shown in cast plates 303 and 304, a The person skilled in the art will recognize that the placement of the openings 306 and 307 in the housing 200 does not matter and is left to a designer of an explosion-proof housing 200. An exemplary embodiment of step capacitors 308 and 309 is illustrated in FIGS. Figures 7 and 8, and described below. An adapter may also be provided to place the capacitors step capacitors 308 and 309 within an opening. Figure 4 is a cross-sectional view of the explosion-proof housing 200. The cavity 400 is the space around the flow tubes 103A and 103B which is enclosed by the housing 200. The cavity 400 provides a space between the walls of the housing a Explosion test 200 and the components of the flow meter assembly 10. The space prevents the heat coming from the components from being applied to the walls of the housing 400, which in turn prevents the heat from being applied to a volatile material outside. of the housing 200. The volume of volatile material that can be enclosed in the cavity 400 must be less than the volume of volatile material required to generate an explosion having a sufficient pressure that could cause a crack in a wall of the housing 200 so that the 200 housing maintain structural integrity during an explosion.

A manifold for a Coriolis flow meter having an explosion-proof housing - Fig. 5 Fig. 5 illustrates a preferred exemplary embodiment of a manifold 500 which can be used either as an input manifold 102 or as an output manifold 102 ' . In a preferred embodiment, manifold 500 is melted as a piece during manufacture. However, those skilled in the art will recognize that the different components of manifold 500 may be melted or constructed separately and then assembled in one piece. For simplicity and to reduce costs, the manifold 500 is interchangeable as an input manifold 102 and an output manifold 102 '. However, separate multiples can be made for the input manifold 102 and the output manifold 102 '.

Connector elements of flow tubes 502 and 503 are attached to the flow tubes 103A-and 103B (shown in Figure 1) by means of orbital welding or some other method. The flow tube connecting members 502 and 503 each receive material from or direct material into the flow tubes 103A and 103B (shown in Figure 1). A flow path within the manifold 500 connects the flow tube connecting elements 502 and 503 to the inlet / outlet 505. The inlet / outlet 505 is connected to a flange 101 or 101 '(shown in Figure 1) and receives material from or return material to a pipeline. The manifold 500 is attached to the separator 106 by a spacer fastener 501, which is an element that is configured to coincide with the spacer 106. Although the spacer fastener 501 is illustrated as a circular ring element, the Those skilled in the art will recognize that the shape of the element 401 must coincide with the shape of the separator 106. The molten plate 504 is a base of the explosion-proof housing 200 which is fixed to the manifold 500. In a preferred embodiment, the molten plate 504 is fused with the manifold 500 and this reduces the number of welds to fix the explosion-proof housing 200 to the Coriolis 5 flowmeter. The melting of the molten plate 504 in the manifold 500 also reduces the number of welds -in the flowmeter 5 that must be inspected. Another advantage of the manifold 500 is the use of ribs, such as the ribs 505. The ribs reduce the amount of material that is required to melt the manifold 500. This reduces the cost of the manifold 500, as well as the susceptibility of the manifold 500 to the cracking.

A cross-sectional view of a flow path through the manifold 500 - FIG. 6 FIG. 6 illustrates a cross-sectional view of the manifold 500 along the line 6 of FIG. 5. The flow path 600 carries material through the manifold 500. The flow path 600 has a minimum volume before the flow path 600 is divided into a first flow tube path 601 and a second flow tube path 602. The minimum volume before division into the paths of separate flow tube is provided by moving the divider 604 near the inlet / outlet 505. The divider 604 is a wall exiting the interior of the flow path 600 to divide the material flow into a first flow tube path 601 and a second flow tube path 602. This solves the problem of having a large volume that forms an accumulation before the 604 splitter. If the material is allowed to accumulate, the swirls in the flow of the The material can drop the pressure of the material flowing through the flow tubes 103A and 103B. After the material enters the first flow tube path 601 or the second flow tube path 602, the flow tube paths 601 and 602 are bent to create a flow path through the manifold 500 to or from the flow tubes 103A and 103B (see figure 1).

A capacitor step capacitor for an explosion-proof housing 200 - Figs. 7 and 8 Figure 7 illustrates one mode of a step capacitor 700 for the explosion-proof housing 200. The capacitor step capacitor 700 is an opening that allows the conductors coming from the interior of the explosion-proof housing 200 pass through the housing to connect with the electronic components outside the explosion-proof housing 200 while maintaining the seal of the explosion-proof housing 200 (see Figure 3).

Two examples of the step capacitor 700 are the step capacitors 308 and 309 illustrated in FIG. 3. One type of capacitor step capacitor is simply to encapsulate the solid conductors in an opening in a wall of the explosion-proof housing. However, the encapsulation of the conductors within the housing is not desirable because any error in the encapsulation process requires that the entire housing be discarded. The use of a capacitor pass capacitor allows the conductors to be the only path through which a flame or hot volatile material can escape from the housing 200. Any other space between the capacitor step capacitor and the walls of the housing provides a path of flame long enough to cool the flame or hot gas to prevent ignition of the outside environment. Although the next pass capacitor 700 is given as an example, one skilled in the art will recognize that any aperture having conductors providing a sufficient flame path for use in the explosion proof housing 200 can be designed.

In an exemplary embodiment that is preferred, the step capacitor 700 is a cylindrical metal element that fits into an opening, such as the opening 306 or 307 in the molten plates 303 and 304 of the explosion-proof housing 200. The capacitor Pass capacitor 700 is a cylindrical element having a first end and a second end. A first end of the capacitor pass capacitor 700 has a cylindrical member 701 that projects outwardly from the circumference of the first end. A second end of the pass capacitor 700 is a cylindrical protrusion 702 extending outwardly from the center of the element 701. The cylindrical protrusion 702 is placed within an opening with minimal spacing between the sides of the aperture and the outer circumference of the aperture. the cylindrical protrusion 702. When the capacitor step capacitor 700 is inserted into an aperture, the protrusion 702 extends through the opening and the element 701 is fixed to the wall surrounding the opening. The element 701 is then welded or otherwise fixed to the wall adjacent to the opening. Figure 8 illustrates a cross-sectional view of the pass capacitor 700. The cross-sectional view reveals the components of the pass capacitor 700. The first end of the pass capacitor 700 has a recessed cavity 801 extending at least substantially through from the step capacitor 700 to a base 802 on a second end of the capacitor capacitor 700. The base 802 has openings (not shown) a plurality of conductors 803 extend from the cavity 801 through the openings in the base 802 The drivers may include but are not limited to cables 110, 111 and 111 '. A potting material 804 is then injected into the cavity 801 and can also be injected into the openings of the base 802. The potting material 804 fills the space between the conductors 803 to keep the conductors 803 in place and to seal the pass capacitor 700 for preventing an explosion from escaping through an aperture in the capacitor pass capacitor 700. The capacitor pass capacitor 700 is placed within an aperture 800 in the following manner. The element 701 rests on the side of the wall 811 adjacent the opening 800 in the explosion-proof housing 200. The element 701 is welded or otherwise fixed to the wall 811. The protrusion 702 then extends through the The opening. Each cable within the housing is then fixed to a conductor 803 in a capacitor capacitor passage 700 on a second side of each conductor 803 and is also connected to the electronic measurement component 20.

An excitation system for a Coriolis flowmeter - Figs. 9, 11 and 12. Figure 9 illustrates an excitation system 104 for a preferred embodiment of Coriolis flow meter 5. In an exemplary embodiment that is preferred, driver 104 is a coil and magnet assembly. One skilled in the art will note that other types of excitation systems may be used in conjunction with the explosion-proof housing 200 of the present invention. The exciter 104 has a magnet assembly 910 and a coil assembly 920. Clamps 911 extend out in opposite directions from the magnet assembly 910 and the coil assembly 920. The clamps 911 are wings extending outwardly from the base flat and have a curved edge substantially on a bottom side that is formed to receive a flow tube 103A or 103B. The curved edge 990 of the clamps 911 is then welded or otherwise secured to the flow tubes 103A and 103B to attach the exciter 104 to the Coriolis S flow meter. The magnet assembly 910 has a magnetic shunt 902 as a base. The clamps 911 extend from a first side of the magnetic shunt 902. The walls 913 and 914 extend outwardly from outer edges of a second side of the magnetic shunt 902. The walls 913 and 914 control the direction of the magnetic fields of the magnet 903. perpendicular to the coils of the coil 904. The magnet 903 is a substantially cylindrical magnet having a first and a second end. The magnet 903 is placed in a magnet sleeve (not shown). The magnet sleeve and magnet 903 are fixed to a second surface of the magnetic shunt 902 to secure the magnet 903 in the magnet assembly 910. The magnet 903 typically has a pole (not shown) attached to its second side. The magnet pole (not shown) is a cap that is placed on the second end of the magnet 903 to direct the magnetic fields in the coil 904. The coil assembly 920 includes the coil 904 and the coil 905. the coil 905 is attached to a clamp 911. The coil 905 has a reel that comes out from a first surface around which the coil 904 is wound. The coil 904 is mounted on the coil 905 opposite the magnet 903. The coil 904 is connected to the cable 110, the which applies alternating currents to the coil 904. The alternating currents cause the coil 904 and the magnet 903 to attract and repel each other, which in turn causes the flow tubes 103A and 103B to oscillate in opposition to each other. Figure 11 illustrates a cross section of a conventional coil 1105, which can be used as the coil 905 (see Figure 9). The conventional coil 1105 is machined from a solid rod of a material such as aluminum. Figure 12 illustrates an alternative coil 1205 that can be used as a coil 905 (see Figure 9). The alternative coil 1205 is pressure cast, which allows it to be hollow. This allows the coil 1205 to have significantly less mass than the conventional coil 1105. The above is a description of a Coriolis flowmeter having an explosion-proof housing. It is contemplated that those skilled in the art can and will design alternative explosion-proof housings for Coriolis flowmeters that violate the explosion-proof housing as described in the following claims either literally or by means of the Equivalent Doctrine.

Claims (7)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A characterized Coriolis flowmeter having at least one flow tube which is substantially U-shaped, an excitation system fixed to said at least one flow tube for vibrating said at least one flow tube and sensors fixed to said at least one flow tube for measuring the oscillations of said at least one flow tube in response to said excitation system vibrating said at least one flow tube and for transmitting information about said oscillations to an electronic measuring component (20), an input manifold fixed to an inlet end of said at least one flow tube wherein said inlet manifold directs a flow of material into said at least one flow tube an outlet manifold attached to an outlet end of said at least one flow tube to direct said material flow from said at least one flow tube into a connected pipe; and said flow meter is further characterized by: an explosion-proof housing enclosing said at least one flow tube said excitation system and said sensors in which the explosion-proof housing is adapted to contain an explosion of volatile material on within said explosion-proof housing and prevents sparks and high temperatures within said explosion-proof housing from igniting volatile materials outside said housing, and wherein said explosion-proof housing has a first end attached to said input manifold and a second end attached to said output manifold for enclosing said at least one flow tube in said housing, further comprising: a substantially U-shaped bend between said first end and said second end of said explosion-proof housing wherein said substantially U-shaped fold is defined as an arc between said first end and said second end of said explosion-proof housing for distributing the voltage applied to said explosion-proof housing on said arc.

2. The Coriolis flowmeter according to claim 1, characterized in that it further comprises: a first conductor having a first end connected to said excitation system within said explosion-proof housing and having a second end connected to an electronic component of measurement outside said explosion-proof housing; at least one opening in said explosion-proof housing through which said first conductor passes from within said explosion-proof housing to the outside of said explosion-proof housing; and a flame path including said first conductor through said opening, wherein the flow path has a length sufficient to cool hot volatile materials that escape through said path.

3. The Coriolis flowmeter according to claim 2, characterized in that it further comprises: second conductors having a first end connected to said sensors inside said explosion-proof housing and a second end connected to said electronic measurement component for transmitting signals from said sensors up to said electronic measurement component, wherein said second conductors pass from the interior of said explosion-proof housing to the outside of said explosion-proof housing through said at least one opening and wherein each of said said second conductors define a flame path having a length sufficient to cool a hot volatile material that escapes.

4. The Coriolis flow meter according to claim 1, characterized in that said at least one flow tube includes a first flow tube and a second flow tube, and said input manifold comprises: an inlet opening for receiving a flow of material that comes from a pipe; a first outlet providing a first flow from said inlet opening to said first flow tube; a second outlet providing a second flow from said inlet opening to said second flow tube; and a divider near said inlet opening that divides said flow coming from said inlet opening in said first flow and said second flow, wherein the divider is close to said inlet opening to minimize the volume in a flow path within of said inlet manifold from said inlet opening to reduce swirls in said flow.

5. The Coriolis flowmeter according to claim 4, characterized in that said explosion-proof housing is divided into a first middle section and a second middle section divided along a longitudinal axis between said first end and said second end of said housing Explosion proof, wherein said first middle section and said second middle section are joined to each other and said inlet manifold and said outlet manifold at the time of assembly to enclose said at least one flow tube.

6. The Coriolis flow meter according to claim 4, characterized in that said input manifold comprises: a first molten plate of said input manifold having a first surface; at least one outlet opening of the manifold on said first surface of said first molten plate connecting said inlet manifold to said at least one flow tube; and said first end of said explosion-proof housing is attached to said first surface of said first molten plate.

7. The Coriolis flow meter according to claim 4, characterized in that said output manifold comprises: a second molten plate of said output manifold having a first surface; at least one entry aperture of the manifold on said first surface of said second molten plate connecting said output manifold to said at least one flow tube; and said second end of said explosion-proof housing is attached to said first surface of said second molten plate to enclose said at least one flow tube.