MXPA97007026A - Cable entry sealed to accommodate instrument and sell method - Google Patents

Abstract

The present invention relates to an instrument housing having an upper part and a base joined together with a sealing material, a cable entry port comprising: a plurality of cables with insulation in which the insulation is removed where the cables run through the sealing material, a plug disposed in an opening in the base, where the plurality of cables run through the cable in the sealing material, and a ventilation that runs through the plug in the housing in where ventilation is adapted to close after gas has been evacuated or introduced inside the housing to reduce humidity inside the housing prior to sealing

Description

CABLE ENTRY SEALED TO ACCOMMODATE INSTRUMENT AND SEALING MEDIUM TECHNICAL FIELD The invention relates to the sealing of cable entry in instruments for measuring quantities such as electricity, gas and water consumption. DESCRIPTION OF BACKGROUND TECHNIQUE In the field of water meters, a turbine and other measuring device was connected to the water supply line. The water consumption units are counted and displayed by a recording unit which is mounted on the upper part of the flow measurement housing. The screen can be a type of quadrant or a type of odometer or a combination of these. The recording unit is operated by electromagnetic coupling, so that the wires are not required to be connected to the flow measurement housing to the registration unit. Inside the register there is a pulse transmitter as described in Strobel et al., U.S. Patent. No. 4,868,566, entitled "Flexible Piezoelectric Switch Activated Metering Pulse Generators". This pulse transmitter unit converts mechanical movements to electric pulses. In certain units, the pulse must be transmitted via cables to certain remote repeater units for transmission to a reading unit. The need for cable entry presents a sealing problem, particularly when the recording unit is to be used in harsh environments such as underground pits, where moisture prevails. There is an additional problem to assemble and manufacture the registration unit to evacuate air and introduce a gas such as helium to keep the area of the record glass in a transparent, readable state, similar to that of a hand clock. There is another additional technical problem with cables that enter an instrument housing. It has been found that in certain circumstances, moisture can be braided in a housing through an insulated wire between the cable conductor and the insulation. The general objective of the present invention is to make improvements in the box and methods for sealing the registration unit particularly in a region where the cables enter the unit. COMPENDIUM OF THE INVENTION The invention relates to a sealed instrument housing having two parts and a method for sealing said housing. A sealed cable inlet port has a body for sealing the material disposed between the upper part and the base of the instrument housing and a plurality of insulated cables in which the insulation is removed where the cables run through the sealing material . A plug is placed in an opening in the base, where the two wires run through the plug in the sealing material. Ventilation is spread through the plug in an interior space in the housing and the vent is adapted to close after a gas has been passed through the vent to reduce humidity inside the housing prior to final sealing. The stripping and sealing of the cables at a seal junction of the housing prevents moisture from being packaged in the housing through the insulated wires. The invention provides a seal with a very low leak rate.

The invention provides significant advantages in the manufacturing cost of the meter record assembly. The invention provides a continuous cable from the inside of the register to the outside, eliminating electrical connections with short bridges. The invention can be applied to many types of instrument boxes, whenever a sealed cable entry is necessary. In the method of the invention, a plug is provided in a side wall of a housing base to be sealed. The plug includes a vent and at least two passages to receive cables. A pair of wires are separated from the insulation in an area that will be sealed. The cables are placed in the passages in the cap while placing the unlined portion of the cables in a region that will be filled with the sealing material. The sealing material is added in a joining region between a top part and a bottom part of the housing. The sealing material is then cured. The gas content within the housing is then altered using ventilation. In a preferred embodiment, this is achieved by evacuating air and filling the instrument with helium. The ventilation is then closed to complete the sealing of the housing. Other objectives and advantages, in addition to those discussed above, will be apparent to those of ordinary experience in the art of describing the next preferred embodiment. In the description, reference is made to the accompanying drawings, which form a part thereof and which illustrate examples of the invention. Said examples, however, are not exhaustive of the various embodiments of the invention and, therefore, reference is made to the claims after the description to determine the scope of the invention BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a top plan view of the meter registration assembly incorporating the present invention, Fig. 2 is a bottom plan view of the assembly of fig 1 with separate parts; Fig. 3 is an elevated sectional view of the assembly taken in the plane indicated by line 3-3 in Fig. 2; Fig. 4 is a detailed view of a portion of the assembly of Fig. 2, Fig. 5 is a detailed sectional view taken in the plane indicated by line 5-5 in Fig. 4, Fig. 6, is a detailed sectional view taken in the plane indicated by line 6-6 in fig 4, and Fig. 7 is a detailed sectional view taken in the plane indicated by line 7-7 in Fig. 4 DETAILED DESCRIPTION OF THE PREFERRED MODE With reference to Figures 1-3, the invention is incorporated into a meter registration assembly 10 in which the insulated cables 21 are in a region near the base 12. The record set 10 It is shown without a protective plastic cover that is added to complete the meter registration unit. The assembly 10 includes a glass or cristaMI dome and a base 12 provided by a thin brass metal plate that has been formed and configured to add certain aspects. The glass 11 is attached to the base 12 by a sealing material 16, which may be one of many suitable epoxy adhesives known in the art. Looking through the glass 11 in Figure 1, there is observed a dial indicator lever 13, a dial face 14 and an odometer assembly 15. As seen in Fig. 3, the face of the dial 14 is part of a plastic structure that is supported by a base of the structure 24 of the plastic material that is formed in a complex configuration. As further observed in Fig. 3, the register unit 10 has a magnetic coupler 17 which is rotated by magnetic forces controlled from below by a water turbine unit (not shown). The magnetic coupler 17 is mechanically connected through a gear train (not shown) to drive the odometer 15 and the handle of the dial 14 to display the accumulated consumption. The magnetic coupler 17 is also mechanically connected to drive a cam 18 seen in Fig. 2. When the cam 18, having the shape of a toothed gear, is advanced by a position, a leaf spring 19 cantilevered at one end has a free end that moves laterally and then moves back to its original position. This bending movement of the leaf spring 19 generates a pulse of the pulse transmitter unit 20 as explained in Strobel et al., US Patent No. No. 4,868.56, entitled "Flexible Piezoelectric Switch Activated Metering Pulse Generators". The pulse transmitter 20 is connected by two cables 21 to another equipment for counting and reporting accumulated pulses. Cables 21 are marked for polarity. The cables 21 are normally conductors 33 with insulation material 31 of polyvinyl chloride (PVC) protection. In the preferred embodiment, conductors 33 are solid cable conductors. It has been discovered that if a seal material 16 such as adhesive 16 is filled around the insulated wires 21 at the point of entry into the recording unit 10, then moisture can enter through the wire between conductors 33 and the insulation 31. The invention provides a plug 22 in the form of a ring of elastomeric material that projects through an opening 34 in a side wall 38 of the base 12 (Figs 6 and 7). The ring 22 has a flange and slot portion 35 for anchoring it in the side wall 38 and for preventing it from being pulled through the opening 34. The ring 22 has three holes or passages 36 (Figs. 6, 7), two for the cables 21 and a third passage 37 for receiving a ventilation 23 lined by a length of copper tube material. The cables 21 pass through the ring 22 and are then received in the guides 27 (Figs 2, 4) formed by parallel barriers 30 at the base of the structure 24. From there, the cables 21 run through the supports 25, 26 on the base of the structure 24, and then connected to the pulse transmitter 20. The invention provides the unlined portions of the cables 29 in the region that is filled with sealing material 16. This sealing material 16 is first filled to a junction region 28 between the glass 11 and the base 12 and between the side wall 38 and a circular wall 39 formed by the base of the structure 24 (Figs., 7). The space between the side wall 38 of the base of the register 12 and circular wall 3 of the base of the structure 24 is partially occupied by two semicircular ribs 40 (Figs 2, 4) formed in the base 12. The ribs 40 have ends separate opposites so that the cables 21 and the ventilation tube23 can enter each other. This provides a slightly longer cross section to the joined region 28 so that the sealing material 16 is filled around the stripped portions 21. The use of the sealing material 16 over the stripped portions 29 prevents moisture from entering through. cable below the insulation 33 and inside the recording unit 10.

The rings 22, cables 21 and sealing material 16 are all installed in the assembly of the glass 11 to the base 12. During assembly the ventilation 23 (Figure 7) prevents the air pressure from increasing inside the unit 10 during the assemble The air is then evacuated through the vent pipe 23, and a gas is introduced into the dry interior space 41 and prevents moisture from accumulating inside the register unit 10. This gas can be either helium or a dry nitrogen. can be used to seal the interior space 41 in the register 10. The vent pipe 23 is then closed at location 32, preferably by welding, but can also be missed by other techniques such as welding, crimping or bending, or by a combination of these . This has been a description of examples of how the invention can be carried out. Those of ordinary skill in the art will recze that various details can be modified to arrive at other detailed embodiments and these embodiments will be within the scope of the invention, For example, while solid conductors are advantageous, conductors while they may also be used. in the invention provided that the steps for sealing between the individual strips are carried out with a sealing or welding adhesive. Therefore, to inform the public of the scope of the invention and the embodiments covered by the invention, the following claims are made.

Claims (19)

1. CLAIMS 1. In an instrument housing having an upper part and a joined base together with a sealing material, a cable entry port comprising: a plurality of cables with insulation in which the insulation is removed where the cables run through the sealing material; a plug disposed in an opening in the base, wherein the plurality of cables run through the cable in the sealing material; and a vent running through the plug in the housing where the vent is adapted to close after gas has been evacuated or introduced into the housing to reduce humidity inside the housing prior to final sealing.
2. 2. The cable entry port of claim 1, wherein the ventilation further comprises a metal tube.
3. 3. The cable entry port of claim 1, wherein the plug is a ring of elastomeric material and wherein the base has a side wall that rises from a bottom, the side wall having an opening in which it is anchor in ring.
4. 4. The cable entry port of claim 1, wherein the cables include solid conductors wherein the insulation is an insulating material of polyvinyl chloride.
5. 5. The cable entry port of claim 1, wherein the cables include conductors and insulation and wherein the insulation is polyvinyl chloride insulating material.
6. 6. The cable entry port of claim 1, wherein said cable entry port is included in an instrument housing.
7. 7. The cable entry port 1, wherein said cable entry port is included in a housing for a utility meter.
8. The cable entry port of claim 1, wherein the plug is a ring of elastomeric material with first and second passages for receiving cables and a third passage for receiving ventilation.
9. 9. A sealed instrument comprising: a housing having an upper part and a base; an instrument mechanism contained within the housing when the upper part is assembled to the base; a body of sealing material joining the upper part to the base and forming a seal where the upper part is joined to the base; a plurality of insulated cables in which the insulation is removed where the cables run through the body of the sealing material; a plug disposed in an opening in the base, wherein the plurality of wires run through the plug in the sealing material; and a vent operating through the plug in the housing, wherein the vent is adapted to close after a gas has been evacuated or introduced into the interior of the housing to reduce humidity inside the housing prior to final sealing.
10. The sealed instrument of claim 9, further comprising a structure within the housing of the instrument having a circular wall that forms an internal boundary for a sealing region and said structure forming guides for the cables to enter the interior of the instrument housing.
11. The sealed instrument of claim 9, wherein said instrument is a register for measuring utility.
12. The sealed instrument of claim 9, wherein the vent further comprises a metal tube.
13. The sealed instrument of claim 9, wherein the cables include solid conductors and wherein the insulation is polyvinyl chloride insulating material.
14. The sealed instrument of claim 9, wherein the cables include conductors and the insulation wherein the insulation is an insulating material of polyvinyl chloride.
15. 15. The sealed instrument of claim 9, wherein the plug is a ring of elastomeric material with first and second passages for receiving cables and a third passage for receiving ventilation.
16. 16. A method for assembling a sealed housing, the method comprising: providing a plug in a side wall of a housing base to be sealed, the plug including a vent and at least two passages for receiving cables; stripping a plurality of insulation cables in portions of the cables to be sealed; placing the cables in the passages in the stopper while the stripped portions of the cables are placed in a region to be filled with a sealing material; adding the sealing material in a joining region between a top part and a bottom part of the housing; cure the sealing material; change the gas content inside the housing using ventilation; and close the ventilation to complete the sealing of the housing.
17. 17. The method of claim 16, wherein said wires are solid conductors with polyvinyl chloride insulation.
18. 18. The method of claim 16, wherein the air is evacuated and the yarn is introduced through the vent.
19. 19. The method of claim 16, wherein the vent is a tube and wherein the vent is closed by welding an open end.