Multi-channel manometer with independent fluid level adjustments

A manometer for multi-channel pressure measurement is presented which includes two or more manometer channels, where each channel includes an independent fluid level adjustment. Also included is a method for calibrating multiple channel carburetors using a manometer having multiple channels each having an independent fluid level adjustment.

TECHNICAL FIELD

The present invention relates generally to devices for measurement of pressure and more particularly to manometers for synchronization of engine carburetors.

BACKGROUND ART

The carburetor is a device that mixes air and fuel for an internal combustion engine. The majority of motorcycles and many snowmobiles and outboard motors still are carbureted due to lower weight and cost compared to fuel-injected engines. Some carbureted engines have a single carburetor, though the modern trend is to use multiple carburetors, of two to eight carburetors. The carburetor works on Bernoulli's principle, which is that moving air has lower pressure than still air, and that the faster the movement of the air, the lower the pressure. The throttle or accelerator controls the amount of air that flows through the carburetor. Faster flows of air entering the carburetor draws more fuel into the carburetor due to the partial vacuum that is created. To function correctly under all conditions, most carburetors require tuning, and for engines with multiple carburetors, it is important that the carburetors be tuned together to provide balanced performance.

A manometer is a pressure measuring instrument which is typically used when adjusting carburetors, whether single or multiple. It uses a column of liquid whose height in a glass tube indicates the pressure which is applied to the openings of the tube. Manometers can be of the type referred to as an “open-end manometer” which is generally “U-shaped” and has both ends open. One of the open ends is typically open to atmospheric pressure and the other end is then connected to a pressure source to be measured. By comparing the levels in the two legs of the U structure, the pressure of the pressure source can be measured compared to atmospheric pressure.

The second type of manometer in common use is referred to as a “closed-end manometer”, where one end is closed and thus a vacuum source connected to the open end pulls against the liquid in the closed tube. This generally gives a measurement of pressure which is lower than atmospheric pressure.

When using manometers or other pressure measurement devices in tuning multiple carburetors in a vehicle, the goal is generally to have the air flow (and thus pressure) in each of the carburetors match as closely as possible to each other. Since it is the relative pressure in each carburetor with respect to each other that is important, the absolute pressure in each channel is not usually a concern. Thus, the purpose of using a manometer for pressure measurement is generally to equalize the pressures in all of the carburetors. It may be possible to do this with a single channel manometer, by noting the pressure in a first carburetor and then connecting the single channel manometer to each successive carburetor in turn, but this is a time consuming and inefficient method because carburetor adjustments affect engine performance and engine performance affects the pressure of previously adjusted carburetors, so it would have to be an iterative process, which would be very time consuming and with less assurance of success. It would be easier and more efficient to be able to monitor all carburetors simultaneously, especially in cases where there may be some cross-effect, whereby the adjustment of a second carburetor affects the performance of the first.

Additionally, it would be an advantage if the fluid-level line in each of the channels of a multi-channel manometer could be individually adjusted, so that there would be maximum flexibility in the calibration of the multi-channels with respect to each other and to a pressure source, such as one of the carburetors in a multi-carburetor engine.

Thus, there is a need for a multi-channel manometer with independent channel fluid-level adjustments for calibration.

DISCLOSURE OF INVENTION

Accordingly, it is an object of the present invention to allow for the tuning of multiple carburetors with a single device.

Another object of the invention is to provide a manometer with multiple channels.

And another object of the invention is to provide a manometer with multiple channels which each have a fluid-level adjustment.

A further object of the present invention is to provide multiple manometer channels which can be adjusted in relation to each other independently.

An additional object of the present invention is to provide a manometer which does not use mercury as a level indicator fluid.

Yet another object of the present invention is to provide a tool in which multiple manometers are grouped together in a single device.

Another object of the present invention is to provide a manometer with multiple channels that can be used independently. The tool can be used as a 1, 2, 3, or 4 channel manometer.

Briefly, one preferred embodiment of the present invention is a manometer for multi-channel pressure measurement which includes two or more manometer channels, where each channel includes an independent fluid level adjustment. Also included is a method for calibrating multiple carburetors using a manometer having multiple channels, each having an independent fluid level adjustment.

An advantage of the present invention is that multiple carburetors on the same or separate vehicle can be adjusted simultaneously.

Another advantage of the present invention is that multiple pressure-measuring devices are grouped in a single device so that they may be easily compared side-by-side.

And another advantage of the present invention is that each of the multiple channels is independently adjustable to set a reference-line for each, or to set a common reference-line used by all channels.

A further advantage of the present invention is that adjustment screws for each channel are grouped in a configuration that is easily accessible for manipulation.

A yet further advantage is that the multiple manometer channels are grouped in a free-standing housing that provides a stable base of support for the manometers.

Another advantage of the present invention is the free standing housing provides reference marks so the user can clearly see when the fluid-levels of the multiple channels are aligned.

And another advantage of the present invention is that each channel is independent of the other channels allowing the user to use as few or as many of the channels as they need.

A further advantage of the present invention is that the manometer does not have to be kept in the upright position while being used or stored to prevent the level indicator fluid from running out of the reservoirs.

These and other objects and advantages of the present invention will become clear to those skilled in the art in view of the description of the best presently known mode of carrying out the invention and the industrial applicability of the preferred embodiment as described herein and as illustrated in the several figures of the drawings.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is an adjustable multi-channel manometer, which will be referred to by the reference number10, and thus, for simplicity, shall be referred to as manometer10. A first preferred embodiment of the manometer10is illustrated inFIGS. 1-5, of whichFIG. 1is a perspective view,FIG. 2is a side plan view, andFIG. 3is a front plan view. Generally, the manometer10includes a housing12having a front face14which includes a slanted panel16. The housing12is preferably, but not necessarily, translucent or transparent, so the fluid levels in the housing12may be observed. A number of manometer tubes18are grouped in the housing12, and each manometer tube18includes a column of manometer fluid20. The tubes18and fluid20are included in each of the manometer channels22, along with other elements which will be discussed below. The slanted panel16includes a number of adjustment screws24, of which there is one for each of the manometer channels22. These adjustment screws24are important for setting the reference line5in each channel22, as will be discussed below.

Four manometer channels22are shown in the embodiment ofFIG. 1. These shall be referred to as channel #126, channel #228, channel #330and channel #432. It shall be understood by those skilled in the art that the number of channels is not restricted to four. There could be as few as two channels, and the number of channels could be eight or more, depending on the number of devices which are intended to be calibrated. The multi-channel manometer10could be used to tune two carburetors on a vehicle, or could be used to tune eight carburetors on 8 vehicles, etc. Thus, the numbers of channels shown in the illustrations are not to be construed as limitations.

FIG. 1also shows four carburetors, designated as carburetor #1, designated element1, carburetor #22, carburetor #33, and carburetor #44. Carburetor #11is shown to be connected to manometer channel #126by a vacuum line6, and the other carburetors2,3,4are shown to be connected to channels28,30,32respectively in a similar manner. Each carburetor1,2,3,4includes its own adjustment mechanism7which controls the air flow in the carburetor in order to tune its performance. The goal in tuning multiple carburetors in a vehicle is generally to have the air flow in each carburetor match as closely as possible to each other. Since it is the relative pressure in each carburetor with respect to each other that is important, the absolute pressure in each channel is not usually a concern. Thus, the purpose of using a manometer for pressure measurement is generally to equalize the pressures in all of the carburetors.

FIG. 4is a cross-sectional view of one of the manometer channels22as taken through section-line4-4inFIG. 3. It can be seen that the interior of housing12encloses a portion of the manometer channel22. The manometer channel22thus includes a reservoir34which connects to an upright portion36at an angle α38, which can be any one of a great variety of angles, as will be discussed below. The adjustment screw24is seated in a threaded connector portion40, so that the adjustment screw can be easily advanced or retreated down the reservoir34. The o-ring42on the adjustment screw24provides a seal between the adjustment screw24and the reservoir34. Thus, when the adjustment screw24is advanced in the threaded connector portion40, it puts pressure on the manometer fluid20which forces it higher into the upright portion36, which is preferably at a height that is above the top of the housing12, and can be easily seen by the user.

This is illustrated inFIG. 5, where an adjustment tool8, preferably a screwdriver, is shown turning the adjustment screw24, forcing manometer fluid20from the reservoir34higher in the upright portion36. Each channel22has its own adjustment screw24, and is therefore independently adjustable. Thus, the levels of manometer fluid20in each channel can be easily calibrated, to set a reference-line5for each. This can be done before the carburetors1,2,3,4are attached, if some target pressure is desired. Alternately, since the pressure in each channel is important only in a relative sense, the reference-line5can be set by attaching each channel22to one of the carburetors1,2,3,4until all are equal.

The manometer fluid20can be of many different types. Some styles of manometers use mercury, since it is a very heavy liquid with a specific gravity of 13.546, and thus a shorter column of fluid is needed in a manometer, relative to lighter fluids. However, mercury is a very toxic material, and involves many safety and disposal problems. Other manometer fluids are available, but their specific gravity ranges from approximately 1.0 to 2.0 which means that the column height is 13 to 6.5 times the equivalent height of mercury when used in an open-end manometer.

As discussed above, the angle α38of the reservoir34relative to the upright portion36, is subject to much variation. The presently preferred angle is in a range of 0-90 degrees, but this angle could vary anywhere from 0 degrees, where the manometer channel describes a “U” structure, to a 90 degree right angle structure, to a full 180 degree structure, where the adjustment screws24are at the bottom of a straight tube18, which is in line with the upright portion36. The angle α38and thus the placement of the reservoir34and adjustment screws24largely depends on what angle the tool will most likely be used in so a static head of manometer fluid20remains above the bottom of the tubes18and a convenient location to access the adjustment screws24for the user. In the present embodiment, the screws were placed at the preferred angle of 15 degrees because the tool is most likely to be used in a vertical or horizontal position. Thus it will be obvious to those skilled in the art that the angle α38can be configured wherever depending on the intended use of the tool and so the convenience of the user can be best accommodated.

In the embodiment ofFIGS. 1-5, based on the intended use of the tool and for the convenience of the user, the manometer channels22are enclosed in the housing12, which can stand upright upon its housing bottom44, and the slanted panel16is included to more easily provide access to the adjustment screws24.

The present multichannel manometer10can be used for adjusting pressures on multiple devices that require calibrated pressure regulation such as multiple carburetors.FIGS. 6-8show various stages in the process of tuning multiple carburetors using the multi-channel manometer10of the present invention. InFIG. 6, it will be assumed that there are four carburetors to be tuned and that the manometer10has four channels26,28,30,32, as discussed above.

All four channels26,28,30,32are first connected to a manifold68, which takes the pressure from carburetor #11and distributes it to all four of the manometer channels26,28,30,32. Through the manifold68, this pressure is applied to all four of the manometer channels26,28,30,32. At this point, the manometer channels26,28,30,32have not been calibrated, so even though they are exposed to the same pressure, they are at various levels, as shown inFIG. 6. The level in manometer channel #126is chosen as a reference, and the reference-line5, to which the other channels will be tuned, is established as being parallel to this level.

InFIG. 7, the three other manometer channels28,30,32are adjusted by their adjustment screws24until all four channels26,28,30,32are at the reference-line5level.

As shown inFIG. 8, the manifold68(seeFIG. 7) is now detached from the vacuum lines6and the carburetors1,2,3,4are all attached individually to the four manometer channels26,28,30,32. As shown, the levels in the manometer channels26,28,30,32will now vary again, as the pressure produced by the other un-tuned carburetors2,3,4is not uniform, but the reference-line5level still remains as a reference. The remaining carburetors2,3,4can now be adjusted by their adjustment mechanisms7until they all match the reference-line5level. The carburetors1,2,3,4will now all be synchronized.

It will be understood that there are many other variations of procedure for tuning multiple carburetors which may be practiced using the multi-channel manometer, and these will be obvious to one skilled in the art. The previous method thus is not meant to be a limitation, but an example of one use.

FIG. 9shows one of many types of enclosure46for the multi-channel manometer10. This type preferably includes a hanging hook48, by which the enclosure may be hung from handlebars of a motorcycle50(represented here by the dashed lines). The bottom of the enclosure46preferably includes a window52, through which the static fluid level line9of the manometer fluid20, can be seen, if the manometer housing12is translucent or transparent. Level markings54are preferably included to allow easy notation of the relative pressure levels in the manometer channels22. Removable rubber feet56are also preferably included to provide a steady foundation for the manometer10when it is not to be hung by its hanging hook48. Also preferably included are two compartments58, whose lower ends are closed by the rubber feet56. These compartments can provide storage space for vacuum caps, carburetor adaptors, lines, or other items when they are not in use. The adjustment screws can be seen at the top of the included slanted panel16. The enclosure46can also be designed to prevent the adjustment screws24from being backed to far out of the reservoir34causing the o-ring42to leak.

It will be obvious to one skilled in the art that many other variations of enclosures are possible, which may take many other shapes and forms. The present illustration is not to be taken as a limitation.

FIG. 10illustrates an alternate embodiment60, in which the reservoir34is at right angles (90 degrees) to the upright portion36, but which functions in a similar manner to that of the previous embodiment. The housing62of this embodiment60is “L-shaped”, so that its housing bottom64provides a foot66for the device to sit upon. Again, there may be certain advantages to having the adjustment screws24presented at this 90 degree angle, which may be more convenient for the user to reach in certain applications. Only two channels are shown in this illustration, but it will be understood that the number of channels may again be eight or more, and that this illustration is not intended as a limitation on the number or dimensions of this embodiment.

FIG. 11illustrates another alternate embodiment70of a multi-channel manometer with independent reference-line adjustments. Again, four manometer channels22are shown, although this number is not to be taken as a limitation. This embodiment70is an example of an open-end manometer, meaning that the lower end is open to the atmosphere and it must be used in an upright position, rather than being closed, as in the previous embodiments.

The manometer70includes a common reservoir72of manometer fluid20, which is drawn up into the manometer tubes18, when lower than atmospheric pressure is applied to the upper ends74of the tubes18through vacuum lines6. As mentioned above, the common reservoir72is at least partially open to atmospheric pressure, preferably through holes76, which may be fitted with removable covers78to prevent spillage when the manometer70is to be moved, stored or to prevent evaporation.

As referred to above, mercury is used widely as a manometer fluid, but in some states the sale of mercury has been ban because of health and safety concerns. Alternative manometer fluids20are lighter in weight than mercury, and thus are easier to draw up into the tubes18. In order to prevent these manometer fluids20from entering the vacuum lines6and emptying the common reservoir72, as reduced pressure draws it out through the upper ends74, the tubes18must be made longer and extend higher into the air, or the applied vacuum pull must be decreased. In order to make the tool a practical height to store and use in a shop environment and to minimize materials and space requirements, it is desirable to keep the tubes18short. Thus, mechanisms have been included to “bleed” some of the vacuum pressure (actually to introduce a small amount of air at atmospheric pressure into the tubes) to decrease the vacuum pull (increase the pressure). The vacuum lines6, which are connected to the carburetors (not shown), are fitted for this purpose with valves80which can take many different forms, as will be obvious to those skilled in the art. One preferred type of valve80is a needle valve82, which can be adjusted to introduce a small controlled amount of air into the vacuum line6, which is indicated by the arrows pointing into the needle valve82. By adjusting this needle valve82, the reference-line5level can be independently adjusted in each of the channels22.

Another very simple type of valve80is a simple T-connector which attaches to a short tube, which can be crimped to decrease air flow. Many other types of valves can be included including electronically controlled valves, and many types of manual valves.

This alternate embodiment70can be used in much the same manner as the other previous embodiments. All channels22can be attached to a manifold from a single carburetor, the reference-line5levels adjusted, and then the vacuum lines6attached to the various carburetors for individual adjustment compared to this reference-line standard.

INDUSTRIAL APPLICABILITY

The present multi-channel manometer10is well suited generally for adjusting pressures on multiple devices that require pressure regulation or synchronization such as multiple carburetors on a single motor, or for tuning multiple carburetors on separate motors. When using manometers or other pressure measurement devices in tuning multiple carburetors on a motor, the goal is generally to have the air flow (and thus pressure) in each of the carburetors match as closely as possible to each other. Since it is the relative pressure in each carburetor with respect to each other that is important, the absolute pressure in each channel is not usually a concern. Thus, the purpose of using a manometer for pressure measurement is generally to equalize the pressures in all of the carburetors. It is easier and more efficient to be able to monitor all carburetors simultaneously, especially in cases where there may be some cross-effect, whereby the adjustment of a second carburetor affects the performance of the first.

The present multi-channel manometer10allows easy simultaneous adjustment of all carburetors. All four channels26,28,30,32are first connected to a manifold68, which takes the pressure from carburetor #11and distributes it to all four of the manometer channels26,28,30,32. To calibrate the manometer channels26,28,30,32, they are exposed to a common pressure, the level in one manometer channel, such as channel #126, is chosen as a reference, and the reference-line5, to which the other channels will be tuned, is established as being parallel to this level. The other manometer channels28,30,32are adjusted by their adjustment screws24until all four channels26,28,30,32are at the reference-line5level.

The manifold68is now detached from the vacuum lines6and the carburetors1,2,3,4are all attached individually to the four manometer channels26,28,30,32. The levels in the manometer channels26,28,30,32will now vary again, as the pressure produced by the other un-tuned carburetors2,3,4is not uniform, but the reference-line5level still remains as a reference. The remaining carburetors2,3,4can now be adjusted by their adjustment mechanisms7until they all match the reference-line5level. The carburetors1,2,3,4will now all be synchronized.

It will be understood that there are many other variations of procedure for tuning multiple carburetors which may be practiced using the multi-channel manometer.

There are many types of enclosures46for the multi-channel manometer10. One type preferably includes a hanging hook48, by which the enclosure may be hung from handlebars50of a motorcycle. The bottom of the enclosure46preferably includes a window52, through which the static level9of the manometer fluid20, can be seen, if the manometer housing12is translucent or transparent. Level markings54are preferably included to allow easy notation of the relative pressure levels in the manometer channels22. Removable rubber feet56are also preferably included to provide a steady foundation for the manometer10when it is not to be hung by its hanging hook48.

Another alternate embodiment60is shown in which the reservoir34is at right angles (90 degrees) to the upright portion36. The housing62of this embodiment60is “L-shaped”, so that its housing bottom64provides a foot66for the device to sit upon.

Yet another alternate embodiment70of a multi-channel manometer with independent reference-line adjustments is that of an open-end manometer, meaning that the lower end is open to the atmosphere and it must be used in an upright position, rather than being closed, as in the previous embodiments. This variation of a manometer70includes a common reservoir72of manometer fluid20, which is drawn up into the manometer tubes18, when lower than atmospheric pressure is applied to the upper ends74of the tubes18through vacuum lines6. The common reservoir72is at least partially open to atmospheric pressure, preferably through holes76, which may be fitted with removable covers78to prevent spillage when the manometer70is to be moved, stored or to prevent evaporation.

Alternative manometer fluids20may be lighter in weight than mercury, and thus are easier to draw up into the tubes18. In order to prevent these manometer fluids20from entering the vacuum lines6and emptying the common reservoir72, as reduced pressure draws it out through the upper ends74, the tubes18must be made longer and extend higher into the air, or the applied vacuum pull must be decreased. Thus, mechanisms have been included to “bleed” some of the vacuum pressure (actually to introduce a small amount of air at atmospheric pressure into the tubes) to decrease the vacuum pull (increase the pressure). Vacuum lines6, which are connected to the carburetors are fitted for this purpose with valves80including needle valves82, which can be adjusted to introduce a small controlled amount of air into the vacuum line6. By adjusting this needle valve82, the reference-line5level can be independently adjusted in each of the channels22.

Another very simple type of valve80is a simple T-connector which attaches to a short tube, which can be crimped to decrease air flow. Many other types of valves can be included including electronically controlled valves, and many types of manual valves. In these alternate embodiments60,70all channels22can be attached to a manifold from a single carburetor, the reference-line5levels adjusted, and then the vacuum lines6attached to the various carburetors for individual adjustment compared to this reference-line standard. Thus all variations can provide for easy calibration of multiple carburetors, whether on a single vehicle, or on separate vehicles

Other advantages of the present invention include the ability to use manometer fluids with relatively low specific gravities when compared to mercury in a configuration that is compact and economical to manufacture when compared to electronic and other mechanical alternatives.

For the above, and other, reasons, it is expected that the multi-channel manometer10of the present invention will have widespread industrial applicability. Therefore, it is expected that the commercial utility of the present invention will be extensive and long lasting.