RU2763109C1 - Fire extinguisher pressure indicator - Google Patents

Abstract

FIELD: instrument engineering.

SUBSTANCE: invention relates to the field of instrumentation, in particular to devices for indicating and measuring the pressure of gaseous or liquid media used in fire extinguishers. The device contains a housing (12), a glass (15), a membrane (11) with an O-ring (13), a dial (10), an axis (2) with a screw section (3) and an arrow (18). Between the projections made on the axis (2) and the housing of the indicator mechanism (8) there is a spring element (1) acting on the membrane (11) of the fire extinguisher pressure indicator. In this case, the spring element (1) is made in the form of a plate spring with bent petals (5) interacting with protrusions (7) made on the axis (2) with the possibility of their mutual rotation, and in the center of the spring element (1) there is a central non-circular hole (4), essentially repeating the profile of the screw section (3) of the axis (2) of the arrow (18).

EFFECT: ability to automate the production of parts and assemblies and increases the quality of the display by increasing the angular movement of the arrow.

3 cl, 2 dwg

Description

Technology area

The proposed invention relates to the field of instrumentation, in particular to devices for indicating and measuring the pressure of gaseous or liquid media used in fire extinguishers.

Prior art

Known pressure indicator (RU 82324, G01L 19/08, dated 20.04.2009), containing a housing with a pipe for supplying pressure of the working medium, a transparent cover, a board, an elastic membrane connected to the indicating element by means of a lever-gear mechanism, a return elastic element, in the form of a spiral spring, a sealing gasket and a spacer washer. The disadvantage is the presence of a complex conversion mechanism in the form of a rack and pinion mechanism, as well as the presence of a board.

A known pressure indicator for a fire extinguisher (RU 2042122, G01L 7/00 /, dated 20.08.1995), containing a housing with a channel for supplying the measured medium, a transparent cover, a board, an elastic membrane connected to the indicating element by means of a converting mechanism, in the form of a rod with a screw a groove and a reducer, a returnable elastic element, in the form of a spring, as well as an annular partition. The disadvantage is the presence of a complex converting mechanism in the form of a rod with a screw groove, a gearbox, and an annular partition.

A known device is a pressure indicator (RU 160228, G01L 19/08, dated 23.10.2015), containing a cylindrical body with a channel for supplying the measured medium, a transparent cover, an elastic membrane, an indicating element, a converting mechanism, a returnable elastic element, the cylindrical body has an internal thread and the groove in which the transparent cover is installed, and the end part of the cylindrical body has an external thread, and the sealed gasket is concentrically located at the bottom of the cylindrical body, while an elastic membrane tightly adjoins the sealed gasket, which is held by a plate made in the form of a cylindrical plug, fixed inside the cylindrical body, by means of a threaded connection, moreover, a pressure measurement scale is applied to the end of the board, in addition, the board has a central screw channel and an internal cavity in which a returnable elastic element is installed, which is a flat spiral strip torsion spring connected to the p a re-forming mechanism, consisting of a screw pin located in the central screw channel of the board, one of the ends of the screw pin made integral with the indicating element, and the other end is in contact with the elastic membrane. The disadvantage is the relative complexity of the design, as well as the small amount of movement of the screw pin, which does not allow for a sufficient angle of rise of the screw line of the thread for easy axial movement of the screw pin and rotation of it together with the arrow at a sufficient angle, providing a clear pressure indication.

Common features with the claimed invention are that the selected prototype (RU 160228, G01L 19/08, dated 23.10.2015) has a housing with a channel for supplying the measured medium, glass, a membrane connected to the pointer by means of a converting mechanism, and a returnable elastic element. Signs that prevent the technical result from being obtained are the small amount of movement of the screw pin, which does not allow a sufficient angle of ascent of the screw line of the thread for easy axial movement of the screw pin and rotation of it together with the arrow at a sufficient angle to provide a clear indication of the pressure. The objective of the proposed invention is to develop such a structure that will increase the axial movement of the arrow axis (screw pin) and, accordingly, the angle of rotation of the arrow to improve the indication due to the preliminary deflection of the membrane by the force of the spring element and thereby increase the total movement of the central part of the membrane under the action of the displacing gas pressure when pumping a fire extinguisher and returning it to its original position.

Brief Description of Drawings

FIG. 1 shows the pressure indicator of a fire extinguisher in isometric view with a quarter cutout.

FIG. 2 shows a spring element assembled with an axle in a quarter-cut diameter.

Embodiments of the invention

The fire extinguisher pressure indicator contains a spring element 1 (Fig. 1, 2), an axis 2 with a screw section 3 passing through a central non-circular hole 4. The spring element 1 contains deformed petals 5, in which circular holes 6 are made, and the axial movement of the axis 2 limited by protrusions 7 made in one piece with the axis 2. The spring element 1 is fixed in the housing of the indicator mechanism 8 (Fig. 1) by the protrusions 9 (Fig. 2). On the upper part of the housing of the indicator mechanism 8 (Fig. 1) there is a dial 10 with an image of the installation mark on the green section of the scale, as well as a yellow section of the scale showing excessive pressure and a red section indicating a lack of pressure (not shown in the figure). An o-ring 13 is located between the membrane 11 and the indicator housing 12, forming a sealed sub-membrane cavity 14. In the upper part of the fire extinguisher pressure indicator, glass 15 is installed, kept from moving by the cap 16 and the rubber ring 17. On the upper part of the axis 2 (Fig. 1, 2) arrow 18 is stuffed (Fig. 1).

The device is assembled as follows through circular holes 6 (Fig. 1, 2) and a central non-circular hole 4 made in the spring element 1, the axis 2 is inserted, while deforming the petals 5 of the spring element 1. The extension of the petals 5 is limited by the axis 2 in the range of angles from 8 up to 12 degrees measured relative to the undeformed part of the spring element 1, since further extension of the petals 5 is limited by the size of the lumen formed by the diverging circular holes 6 and the axis 2 clamped by them, until it leaves the central non-circular hole 4. The minimum angle of 8 degrees is chosen from the calculation the magnitude of the relative displacement of the circular holes 6 depending on the change in the angle of inclination of the petals 5 relative to the undeformed part of the spring element 1 to ensure reliable abutment of the axis 2 against the membrane 11 when assembling the fire extinguisher pressure indicator, and the maximum angle of 12 degrees ensures that the axis 2 of arrows 13 does not leave the hole 4 in an intermediate assembly. Such a constructive solution provides the convenience of further assembly of the fire extinguisher pressure indicator. The spring element 1, assembled with the axis 2, is placed in the housing of the indicator mechanism 8, where it is fixed by means of the protrusions 9 (Fig. 2) made on the spring element 1 (Fig. 1, 2), after which the specified assembly is installed in the indicator housing 12, where a rubber ring 13 and a membrane 11 are previously placed and after setting the dial 10, the mechanism is fixed in the indicator case 12, for example, by a crimp or a retaining ring (not shown in the figure). A reference pressure is supplied to the sub-membrane cavity 14, after which an arrow 18 is stuffed on axis 2. On axis 2, an arrow 18 is stuffed with a direction at a special risk, marked in the middle of the green section of the scale (not shown in the figure), shown on the dial 10. After the pressure is released glass 15 is placed from the sub-membrane cavity 14. It is possible to install the arrow before setting the glass 15, taking into account its future rotation under the influence of the pressure supplied to the sub-membrane cavity 14, for which an additional installation risk is applied on the dial 10 (not shown in the figure), but the indication accuracy at this is reduced due to an error in the manufacture of the part.

The device works as follows, when a fire extinguisher is injected with a displacing gas in the sub-membrane cavity 14, the pressure increases, which exerts a bending effect on the membrane 11. Straightening, the membrane 11 compensates for its deflection towards the sub-membrane cavity 14, created by the force of the petals 5, and with a further increase in pressure, it flexes in the opposite direction side, which increases the stroke of the axis 2, and, consequently, the angle of rotation of the arrow 18 and, accordingly, the quality of the indication, this is also facilitated by the small dimensions of the axis 2, the possibility of making it from low-carbon steel and obtaining its screw section by twisting, which with the same axial displacement of the axis 2 provides a larger helix angle of almost double-start thread. In turn, the double-start thread more easily converts the axial movement of the axis 2 into its rotational movement due to the symmetrical expansion of the forces acting in this case. When the pressure in the sub-membrane cavity 14 decreases due to the elasticity of the membrane 11 and the force of the action of the petals 5 on it through the axis of arrow 2, the membrane 11 and, accordingly, the arrow 18 return to its original state, indicating that the fire extinguisher is discharged, while the minimum 6 percent force of the petals 5 of the spring element 1, acting through the axis 2 on the membrane 11, provides its clicks through zero (under-reaching to zero is caused by the permanent deformation of the membrane 11 and the fixing of its periphery) and additional deflection in the opposite direction, the value of which exceeds the loss of the membrane deflection value under the action of the displacing gas, when the increase the deformation of the membrane is reduced by the unit of increase in the pressure of the displacing gas. The maximum 10 percent force is selected from the condition of the greatest difference between the deflection from the action of the petals 5 of the spring element 1 and the loss of upward deflection under the action of the extinguishing gas pressure on it. From the above description, it can be seen that the fire extinguisher pressure indicator has novelty and is industrially feasible by known means, while the design makes it possible to automate the production of parts and assemblies and increases the quality of the indication by increasing the angular movement of the arrow.

Claims (3)

1. A fire extinguisher pressure indicator containing a body (12), glass (15), a membrane (11) with an O-ring (13), a dial (10), an axis (2) with a screw section (3) and an arrow (18), which is different the fact that between the protrusions made on the axis (2) and the housing of the indicator mechanism (8) there is a spring element (1) acting on the membrane (11) of the fire extinguisher pressure indicator, and the spring element (1) is made in the form of a leaf spring with bent petals (5) interacting with the protrusions (7) made on the axis (2) with the possibility of their mutual rotation, and in the center of the spring element (1) there is a central non-circular hole (4), essentially repeating the profile of the screw section (3) of the axis (2) arrows (18). 2. The fire extinguisher pressure indicator according to claim 1, characterized in that the force of the petals (5) of the spring element (1) acting through the axis (2) on the membrane (11) is 6 ... 10% of the force created by the central part of the membrane (11 ) under the action of the extinguishing gas pressure of the fire extinguisher. 3. The fire extinguisher pressure indicator according to claim 1, characterized in that the angle of inclination of the petals (5) of the spring element (1) before the final assembly of the fire extinguisher pressure indicator is 8 ... 12 degrees relative to the undeformed part of the spring element (1).

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