JP2012154702A - Density measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deformation of an elastic member that detects displacement of a float.SOLUTION: A density measuring device comprises a first float 7 that floats and sinks guided by a stem corresponding to the density of fuel oil; a second float 8 that shifts guided by the stem corresponding to the surface level of water; an elastic member 9 that is positioned between the first and second floats 7 and 8 and expands or contracts corresponding to the position of the first float 7; and a means to detect the expansion or contraction of the elastic member 9, wherein the ends, meeting the first and second floats 7 and 8, are respectively provided with accommodating members 71 and 81 approximately equal in length to the overall length of the elastic member 9 when contracted to the extreme.

Description

  The present invention relates to a density measuring function attached to a liquid level measuring device capable of detecting the density of fuel or the like in a fuel storage container of a fueling facility, and more particularly to the structure of a float and an elastic member.

  An apparatus for detecting the density of fuel in a fuel storage container of a fueling facility is, for example, as shown in Patent Document 1, a driving body and a scale that is locked to the driving body and whose elastic displacement indicates the driving force of the driving body. And a magnetostrictive position measuring system for obtaining the elastic displacement of the spring as disclosed in Patent Document 2, for example.

European Patent No. 1881316 Japanese Patent No. 3307610 JP 2010-217082 JP

However, there is a problem that the structure becomes complicated because an extra stopper having a magnet is required only for density measurement.
In order to solve such a problem, the applicant arranges a water float that moves in accordance with the depth of water present at the bottom of the container as shown in Japanese Patent Application No. 2010-136930 in a slidable manner on the magnetostrictive wire. The magnetostriction transmits an electrical signal to the other end of the magnetostrictive wire by a transmission switch provided at one end, and measures the arrival time of the signal generated by magnetic interaction with the magnet provided in the water float. In the liquid level measuring apparatus, a density measuring apparatus was proposed in which a density float that floats and sinks in accordance with the density of the liquid and that interacts magnetically with the magnetostrictive line is connected to the upper part of the water float by an elastic member.

  According to this, a liquid level measuring device having a simple density measurement function can be provided by using the structure of an existing magnetostrictive liquid level gauge, but the coupling structure between the float and the elastic member is clearly defined. Inconveniences such as drastic changes in the liquid level due to oiling to the tank and excessive deformation of the component parts during transportation of the liquid level measuring device, causing plastic deformation of the elastic members arranged between the floats. It was observed.

  In addition, since multiple floats are arranged on the same axis in a vertical relationship via elastic members, there is an offset between floats, there is a limit on the minimum distance between floats, and the minimum measurable value. There was a limit.

The present invention has been made in view of such problems, and an object of the present invention is to improve the contact structure between the float and the elastic member to prevent deformation of the elastic member.
Another object of the present invention is to minimize the minimum value that can be measured.

  In order to solve such a problem, the invention of claim 1 is directed to a first float that is guided by the stem and floats and sinks corresponding to the density of the fuel oil, and corresponds to a water level guided by the stem. A second float that moves, an elastic member that is positioned between the first and second floats and expands and contracts in accordance with the position of the first float, and means for detecting expansion and contraction of the elastic member And an accommodating member having a length of about the full length when the elastic member is maximally contracted is provided at each of the opposing ends of the first and second floats.

  The invention according to claim 2 is formed so that one of the housing members is accommodated in the main body of the float.

  According to the invention of claim 1, the elastic member is protected by the housing member.

  According to the invention of claim 2, in addition to the effect of the invention of claim 1, the minimum distance between the first and second floats can be shortened by the length of one housing member.

1 shows one embodiment of the present invention. FIGS. 1A, 1B and 1C are a top view, a cross-sectional view and a perspective view, respectively, showing the first embodiment of the present invention in a state where two floats are in close contact with each other. FIGS. 2A and 2B are a sectional view and a perspective view, respectively, showing a first embodiment of the float structure of the present invention in a state where two floats are separated from each other. FIGS. 2A and 2B are a sectional view and a perspective view, respectively, showing a second embodiment of the present invention in a state where two floats are in close contact with each other. FIGS. 2A and 2B are a sectional view and a perspective view, respectively, showing a second embodiment of the float structure of the present invention in a state where two floats are separated from each other. FIGS. 2A and 2B are a sectional view and a perspective view, respectively, showing a third embodiment of the float structure of the present invention.

  FIG. 1 shows an embodiment of the present invention, in which a riser pipe 3 is connected to an underground tank 1 and a pit provided on the ground, and the liquid level detecting device characterized by the present invention 4 is installed in the tank 1.

  The liquid level detection device 4 is slidably inserted into the stem 5 located in the oil storage region, and a stem 5 composed of a head portion 10 containing a driving means, a tube that also serves as a housing for a magnetostrictive wire and a detection portion. The oil level detection float 6 is used.

  The stem 5 is constituted by a nonmagnetic metal having rigidity sufficient to resist the tension of the magnetostrictive wire accommodated and external force, and in this embodiment, a pipe made of non-rust steel. Reference numeral 11 denotes a data processing unit.

  The displacement (position) of the float 6 in the system configured as described above is arranged so that the magnetostrictive line in the stem, the piezoelectric element, and the float magnet interact with each other as seen in the invention of Patent Document 3. When a pulse signal is supplied to the coil from the tip side, a signal is generated due to the interaction with the magnetostrictive wire, the piezoelectric element, and the magnet, and it can be measured from the arrival time of this signal.

  The density float 7 characterized by the present invention is slidably disposed on the stem 5 with an elastic member 9 interposed therebetween so as to have a vertical relationship with the water detection float 8. These two floats 7 and 8 are each provided with a magnet (not shown) for position detection for detecting the position by interaction with the magnetostrictive line in the stem, like the oil level detection float 6.

  In this embodiment, the density float 7 applies buoyancy corresponding to the density of the oil liquid, and accordingly, an appropriate tension and pressing force are applied to the elastic body 9 between the float 8 for water detection. The distance L changes corresponding to the density of the oil liquid. This distance L can be detected as a time difference between magnetostrictive signals reaching the magnets of the water detection float 8 and the density float 7.

  The water float 8 moves up according to the water level when water enters the tank. This amount of movement is detected as a magnetostriction signal by a magnet provided in the water float.

2 and 3 show the mutual structure of the density float, the water detection float, and the elastic member, respectively. Each float floats in the water and has a density enough to precipitate in the fuel oil. It is configured as a cylindrical body adjusted to a specific gravity, and at the ends facing each other, the elastic member 9 made of a coil spring having an inner diameter through which the stem 5 can pass is ½ of the contracted length. Cylindrical housing members 71 and 81 are attached.
In this embodiment, each float is equipped with a magnetostrictive wire in the stem and a magnet M that interacts with the piezoelectric element.

  These accommodating members 71 and 81 are fixed by fitting the non-opposing sides to the opposing sides of the floats, respectively, and tapered portions 72 and 82 are provided so that the leading ends of the opposing sides are widened. It has been. In addition, the code | symbols 7a and 8a in the figure show the through-hole of the stem 5, respectively.

  According to this embodiment, when the density float 7 is mounted on the stem 5 so that the water detection float 8 is located below and the elastic member 9 is interposed, the outer periphery of each end of the elastic member 9 is the float 7, 8. Guided by the tapers 72 and 82 at the tips of the housing members 71 and 81, the housing members 71 and 81 of the respective floats smoothly enter.

  In this state, even if each float slides violently on the stem due to a sudden change in the liquid level or an impact during transportation, the opposing tips of the accommodation members 7 and 8 of each float collide with each other and at least elastic Since the space at the time of contraction of the member 9 is secured, the elastic member 9 is not buckled and is not permanently deformed.

  Further, when the floats 7 and 8 move up and down due to water intrusion and density change, the outer periphery of the elastic member 9 is guided by the tapers 72 and 82 of the housing members 71 and 81 of the floats. The floats are smoothly accommodated in the accommodation members 71 and 81 of the floats, and the floats 7 and 8 accurately follow the density of the fuel oil and the level of water that has entered.

  4 and 5 show another embodiment of the present invention. In this embodiment, one of the floats of the above-described embodiment, in this embodiment, the accommodating member 71 'of the density float 7 is replaced by the float 7 It is embedded in the lower cylindrical recess 7b.

  In this embodiment, each housing member 71 ', 81 is formed with elastic member receivers 73, 83 made of a plurality of protrusions or ribs for fixing the elastic member on the back side, and the elastic member 9 has an end portion thereof. Are pushed into the back side of these elastic member receivers 73 and 83 to prevent them from coming off. Further, as in the above-described embodiment, the tapers 72 and 82 are formed so that the side facing the inner peripheral surface is widened at the tip of the accommodating portion.

  According to this embodiment, since one elastic member accommodating member 71 ′ is accommodated in the float 7, the movable range of the float 7 can be expanded to the minimum side by the length L of the accommodating member, and the density can be increased. The measurement range can be expanded.

  FIGS. 6 (A) and 6 (B) show a third embodiment of the present invention. In this embodiment, a rib 84 is provided at the tip of the housing member 81 protruding outside the second embodiment. Further, a projection 74 having a length of about the length of the housing member 81 is formed at the tip of the other housing member 71, and a stopper 75 is formed at the tip.

According to this embodiment, the projection 74 restricts the movement in the direction perpendicular to the axis of the stem, and the retaining member 75 prevents the two floats 7 and 8 from being separated too much and causing deformation of the elastic member 9. .
Further, even if the float 7 and the float 8 collide, the elastic member 9 does not buckle and can be prevented from being permanently deformed.

DESCRIPTION OF SYMBOLS 1 Underground tank 3 Riser pipe 4 Liquid level detection apparatus 5 Stem 6 Oil level detection float 7 Density float 8 Water detection float 9 Elastic member M Magnet

Claims (5)

A first float that is guided by the stem to float and sink according to the density of the fuel oil, a second float that is guided by the stem and moves according to the level of water, and the first and second floats And an elastic member that expands and contracts corresponding to the position of the first float, and means for detecting expansion and contraction of the elastic member, and the first and second floats face each other. The density measuring device is provided with an accommodating member having an entire length at the time of maximum contraction of the elastic member at an end portion of the elastic member. The density measuring device according to claim 1, wherein one of the housing members is formed so as to be accommodated in a main body of the float. The density measuring device according to claim 1, wherein a taper that widens toward the tip end is formed on an inner surface of each of the opposing ends of the housing member. The density measuring apparatus according to claim 1, wherein both ends of the elastic member are fixed to the main members. A magnet is attached to each of the first float and the second float, and a magnetostrictive wire affixed to the stem and a detection unit provided to transmit vibration at one end of the magnet are accommodated. The density measuring apparatus according to claim 1, wherein the density is measured from a difference in arrival time of signals by a magnet.

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