GB2278681A

GB2278681A - Contamination indicator for use in liquids or gases

Info

Publication number: GB2278681A
Application number: GB9311490A
Authority: GB
Inventors: Kenneth Ian Fitzsimmonds
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-06-03
Filing date: 1993-06-03
Publication date: 1994-12-07
Also published as: GB9311490D0

Abstract

Indicator has a replaceable colorimetric element and may be installed in line e.g. as a T piece in a conduit to detect contaminants in lubricating oils or water in compressed air supplies. A ball valve housing a capillary wick inside the ball is further claimed. Indicator materials may be soluble dyes within a carrier material.

Description

An Indicator with a Replaceable Element.

This invention relates to a simple contamination indicator for use in systems which contain liquids, gases or other mediums.

When liquids, gases etc are being stored, conveyed, pumped or treated, it may be very important to the process, to indicate that medium has not been contaminated by the accidental introduction of something else, possibly due to the failure of another part of the system. By way of a broad illustration, a few possible examples are shown below.

Example 1. A compressed nitrogen system. In the event that the compressor seals failed, the nitrogen could be contaminated by lubricating oil from the compressor. It would be desirable to indicate the presence of this oil in the nitrogen.

Example 2. Some compressed air systems use 'dryers' to remove water from the compressed air. If the dryer failed, water would remain in the compressed air as a contaminant. It would be desirable to indicate the presence of water downstream of the dryer.

Example 3. Some bottling processes use vacuum pumps to introduce the liquid into the bottles. When nail varnish is being bottled, the solvent fumes are removed by filters fitted before the vacuum pumps. Failure of the filters would result in solvents being discharged by the vacuum pumps into the atmosphere. It would be desirable to indicate the presence of any solvents, after filtration has taken place.

Electronic systems are widely available to monitor and detect all types and levels of contamination, these are comparitively expensive and complicated, particularly if the process has to be monitored at numerous different points.

Often it would be advantageous to have a simple indicator to show that something has gone wrong at a particular point in the process. In these cases it is unnecessary to have an electronic system to display the level of contamination to the very last part per million.

The invention is an INDICATOR with a REPLACEABLE ELEMENT, which shows that a fluid, gas or other medium being monitored in a system, has a specified contaminant(s) within it. The system could be pipework, receivers, vessels, or any other components/methods used for holding, conveying, measuring or treating the respective medium.

The potential contaminant(s) to be indicated would be specified by the respective application and the indicator unit would be installed to detect this particular contaminant or group of contaminants.

The indicator is fitted into the system by screwing it in place, bolting it in place, or otherwise attaching it into the system. Figure 1 shows the unit screwed into a 'tee piece' in a pipe. Flowing through the pipe is the medium being monitored.

As the medium passes through the tee piece, a sample is introduced into the indicator by employing one or more of the following methods.

i. A conical hole on the stem of the indicator is positioned so that it faces the oncoming medium, this is called the collector. The medium is forced into the internals of the indicator, through the indicator element, to be discharged back into the body of the tee piece via another hole.

(Figure 1).

The collector can be free to spin on the indicator shaft and by shaping the collector so that it is aerodynamic, or so that the collector shape has a small amount of drag, it will automatically align itself with the direction of flow. (Figure 2 and Figure 7.) ii. An orifice is placed facing away from the direction of flow, the shape of the collector body is such that the flow across its surface causes a pressure reduction in the orifice and the medium is sucked via another hole(s) which does not face away from the direction of flow. The sample is sucked into the internals of the indicator, to pass through the indicator element, finally to be discharged through the orifice. (Figure 6).

iii. The device employs both functions i. and ii, a collector facing the flow and also a discharge orifice facing in the opposite direction. The effect would be to increase differential pressure between the inlet and outlet ports, which will increase the flow of the sample through the indicator element. The collector/discharge body can either be fixed as in Figure 11, or free to swivel to that it is self aligning with the direction of flow as shown in Figure 7.

iv. The device can have a small pilot hole which would allow the pressurised medium to flow through the indicator body and pass through the indicator element either to atmosphere (if the medium so allows) or to be piped away elsewhere. (Figure 8).

v. Capillary action by employing a wick.

a) A wick which simply dangles into the liquid and draws a sample into contact with the replaceable indicator element. This has no isolator valve.

b) The wick is constructed from a material which can be preformed. An example of this type of material is the sintered ceramic tubes used in cavity walls to draw out damp from houses. A pre-shaped pellet is fixed inside the ball part of the valve assembly, this pellet has been manufactured so that the surface continues the roundness of the ball.

(The ball valve allows the indicator element to be isolated from the system.) The upper and lower capillary can be a softer material which is pressed into contact with the material contained within the ball.

The lower capillary is brought into contact with the liquid and the wick system will draw liquid into contact with the replaceable indicator element.

Figure 9 illustates the indicator fitted to a bulk head tank connector, on a tank containing liquid. In this instance the system uses a wick which is contained within a ball valve.

vi. Direct connection into the system so that rather than just a sample, the entire media must flow through the indicator element. The unit could have an internal valve system which uses a bypass and vent port, similar to that used in Figure 1, or it could simply be connected in line as shown in Figure 10. In this application the use of the word 'sample' would in fact refer to the complete flow of the media.

vii. Direct connection of the replaceable indicator element alone, into the system either with or without the use of an isolating valve. The element can be simply screwed, or otherwise attached, into a convenient point is the system.

The sample of the medium enters the indicator body and passes through a valve arrangement into the replaceable indicator element. The sample then passes back through the valve back into the system. The valve can be of the rotary type as shown in Figure 1, or a flat face type as shown in Figure 2. The valve arrangement facilitiates the easy removal and replacement of the indicator element without having to take the unit out of service, or having to shut the system down.

The valve can be of a bypass type so that the sample will continue to flow through the stem of the indicator (but not the indicator element itself) when the valve is in the shut position. This is illustrated in Figure 1 where the valve is shown on the normally open position. When the valve is closed by turning the top section through 90 degrees, the inlet port connects with the discharge port. The top part of the valve is restricted to a 90 degree turn, by a small pin which locates in a curved groove in the surface of the mating bottom part of the valve assembly. See Figure 11 and Figure 1.

The valve can also be fitted with a spring loaded ball which will locate into one of two dimples which have been pre-drilled into the surface of the bottom part of the valve assembly. This will provide a positive location for the valve assembly in either the open position or the closed position. See Figure 11.

The sample, having passed through the open valve, enters the indicator element, which comprises of a transparent housing containing the indicator material, see Figure 3. The housing is designed to allow clear visibility as to the colour of the material contained within it. The housing would be constructed from any transparent material which was suitable for a specific application. The indicator element is held in place by a screw thread as shown in Figure 3, or a separate loose ring as shown in Figure 4. The design allows it to be locked in place if required, as in Figure 5.

The indicator material consists of a specially selected powdered soluble dye or chemical, contained within a carrier material. The carrier material also acts as a filter screen to stop the powdered dye or chemical, from leaving the body of the indicator element.

A powdered soluble dye or chemical, is chosen to release its colour, or change its colour in the presence of the relevant contaminant. For example when detecting oil in a system, an oil soluble dye is chosen. The dye is unaffected by water or other materials and remains in its powdered form, but as soon as it comes into contact with oil then its colour is immediately released to visibly stain the carrier material. The same is true for water soluble dyes when they come into contact with water, and solvent soluble dyes when they come in to contact with solvent. Other suitable dyes and chemicals can be selected to react with other potential contaminants, these are encompassed within the carrier material to form the indicator material.

The carrier material could for example be white in colour and contained within the material could for example be a powdered oil-soluble dye which would release a blood red stain upon contact with oil. In this example any gas or non-oil based liquid which had accidentally become contaminated with oil, would result in a clear visual indication of red against a white background inside the transparent housing of the indicator element. The colour of the 'carrier material' and the dye/chemical, can also be chosen to indicate different contaminants. In this way a clear visual and non-expensive indication of contamination is provided.

The indicator element is self contained and is automatically vented when the built in valve is turned 90 degrees to the closed position. The vent port is shown on Figure 1 where the valve is in the open position. The vent port can be piped away if necessary. When the built in valve is closed, the indicator element can then removed and another fitted in its place. The internal valve can then be re-opened and the unit is once more in service.

When in operation a steady flow of sample media will pass through the indicator element.

Claims

1. A simple indicator which can be re-used by fitting a replacement indicator element, for use with any gas or mixture of gases. The unit will show by colour change in the replaceable element, the presence of a particular contaminant or group of contaminants.

2. A simple indicator which can be re-used by fitting a replacement indicator element, for use with any liquid or mixture of liquids. The unit will show by colour change in the replaceable element, the presence of a particular contaminant or group of contaminants.

3. A simple indicator which uses one or more of the following methods for taking a sample of gas or liquid from a flowing system.

i. The use of a cone shaped hole, which faces the direction of flow, ultimately connected to a discharge point which does not face the direction of flow. The differential pressure results in flow from the conical shaped hole to the discharge point.

ii. The use of a discharge orifice in an aerodynamically shaped collector body, which is positioned so that the orifice faces away from the direction of flow. The discharge orifice is ultimately connected to an inlet point which does not face away from the direction of flow. The depression created at the discharge orifice causes a differential pressure which results in flow from the inlet point to the discharge orifice.

iii. A pilot hole which connects to a point, either inside the system or outside the system, which has a lower pressure than the pressure at the collector. The differential pressure created causes flow.

4. A system which uses a free spinning collector body which will align itself with the direction of flow, which in turn then uses any or all of the principles illustrated in Claim 3, to cause flow.

5. A simple indicator which uses a wick or capillary to bring the medium into contact with the replaceable indicator element.

6. A simple indicator with an integral valve which, when in the closed position, allows the replaceable indicator element to be removed whilst the indicator body is still connected to the system.

7. A simple indicator which has an integral bypass port within the valve assembly which will 'short circuit' the collector and discharge port when the valve is in the closed position. This will allow the continued flow from the collector to the discharge port, even with the integral valve in the closed position.

8. A simple indicator which has a vent port which depressurises the indicator element when the integral valve is in the closed position.

9. A replaceable element which shall be fitted to the simple indicator body.

This element shall be for use with a gas or a mixture of gases, and uses powdered soluble dyes or other chemicals to create a colour change. This change being due to the presence of a target contaminant in the gas or mixture of gases, which will release the colour from the dye, or create a colour change in the chemical.

10. A replaceable element which shall be fitted to the simple indicator body.

This element shall be for use with a liquid or a mixture of liquids, and uses powdered soluble dyes or other chemicals to create a colour change.

This change being due to the presence of a target contaminant in the liquid or mixture of liquids, which will release the colour from the dye, or create a colour change in the chemical.

11. A replaceable element which shall be fitted to the simple indicator body.

The element shall contain a powdered soluble dye or other chemicals, and these shall be contained within a carrier material. The carrier material will act as a screen and/or filter, to prevent the ingress of the dye or other chemicals into the rest of the indicator body and hence the system.

The carrier material will also take up the stain from any released colour.

This all to be contained within a housing which will allow the internal material to be viewed.

12. A replaceable indicator element that is constructed to that it simply screws into the indicator body, or is attached to the indicator body using a clamp ring, screws or other suitable fixing arrangements.

13. A replaceable indicator element constructed in such a manner that the inlet and discharge ports contained within the element affect a positive flow through the material contained within the element.

14. A simple indicator which is fitted with replaceable indicator elements.

15. A simple indicator which is fitted with a replaceable indicator element, which can be locked to the indicator main body using a proprietory device such as a padlock, so that the element cannot be removed from the main body, other than by removing the proprietory device.

16. A simple indicator which is fitted with a replaceable indicator element, the valve body may be locked in the open or closed position using a proprietory device such as a padlock, so that the valve cannot be tampered with other than by removing the proprietory device.

17. A simple indicator which can have the indicator element removed, and the inlet & discharge ports which would normally introduce and collect the sample to/from the indicator element, can be connected via tubes/hoses to any other form of inspection or monitoring equipment.

18. A simple indicator element which can be fitted to a proprietory valve which is fitted to a system. By closing the proprietory valve the replaceable indicator element can be removed from the system, although the element would not automatically vent.

19. A simple indicator with its own internal valve system which uses a pin contained within a curved slot, so that the open and closed positions of the valve are 90 degrees apart when the pin reaches either end of the curved slot.

20. A simple indicator which has an internal valve assembly fitted with a spring loaded ball which will locate in one of two dimples. The dimples are positioned so that the spring loaded ball will enter one dimple in the valve open position, and the other dimple in the valve closed position.

This shall provide positive location for the valve in both the open or closed positions.

21. A ball valve which contains a preformed wick material inside the ball, which shall act as a capillary to convey medium to and from other softer wick materials which are either side of the ball and directly in contact with the ball.