GB2195182A

GB2195182A - Liquid level indicators

Info

Publication number: GB2195182A
Application number: GB08720591A
Authority: GB
Inventors: Yoshihisa Inoue
Original assignee: Sakura Instrument Co Ltd
Current assignee: Sakura Instrument Co Ltd
Priority date: 1986-09-17
Filing date: 1987-09-02
Publication date: 1988-03-30
Anticipated expiration: 2007-09-02
Also published as: JP2547547B2; FR2603985A1; GB8720591D0; FR2603985B1; DE3728829A1; JPS6373118A; GB2195182B; DE3728829C2

Description

1 GB2195182A 1

SPECIFICATION

Displacer type liquid level indicator BACKGROUND OF THE INVENTION Field of the Invention The present invention relates generally to liquid Jevel indicators and, more particularly, is directed to a so-called float or displacer type liquid level indicator employing a float or displacer to measure and indicate a liquid level value of the liquid within a tank.

Description of the Prior Art

A known float or displacer type liquid level indicator FLI to which the present invention is applied will be described hereinafter with reference to Figs. 1 A and 1 B. Fig. 1 A is a partly cut-away perspective view, illustrating the state that the liquid level indicator FLI is mounted on a tank T which contains therein liquid L of which the liquid level LL is to be measured. Fig. 113 is an enlarged partly cutaway perspective view of Fig. 1A.

Referring to Fig. 1A, in the conventional displacer type liquid level indicator FLI, a compartment portion 4 is formed of a substantially horizontal tube portion 4A and a substantially vertical tube portion 413 which are coupled to each other so as thereby to become an Lshaped compartment portion. The compartment portion 4 incorporates therein a main portion of the liquid level indicator FLI such as a rewinding drum 1 and so on. A wire 2 having connected a float or displacer 3 at its one or free end is wound at its other end portion around the winding drum 1 and the displacer 3 is floated on the liquid level or surface LL of the liquid L in the tank T. In the liquid level indicator FLI, the lower end of the tube portion 413 is communicated through a short tube portion 21 and a sluice valve (valve) 22 incorporating therein a partition plate 22A to a nozzle portion 23 mounted on the upper portion of the tank T. Thus, the wire 2 passes downward from the winding drum 1 through the tube portion 4B, the short tube portion 21, the valve 22 and the nozzle portion 23 to the liquid level LL, whereby the displacer 3 connected to the free end of the wire 2 is floated on the liquid level LL. In the valve 22, its partition plate 22A is opened and/or closed by a handle lever 2213, and reference numeral 21A designates a lid which is attached to a nozzle 21 B of the short tube portion 21 to close its opening, if necessary. In case where the tank T produces no high pressure, the valve 22 may be removed and the short tube portion 21 may be directly coupled to the nozzle portion 23. In Fig. 1 A, reference numeral 11 designates an indication window attached to the front panel of one end of the tube portion 4A of the compartment portion 4 and through which the liquid can be read out.

With the conventional displacer type liquid level indicator F11 described hereinabove, the following methods are known to check whether the value of the liquid level measured by the liquid level indicator is correct or not upon use.

A. In case of tank generating no high pressure where the valve 22 is not provided (1) The user hangs down a tape 25B of a measuring machine 25 with a weight 25A through another nozzle portion 24 mounted on the upper portion of the tank T to its bottom TB and measures the length of the wetted portion of the tape 25B as shown in Fig. 1 A. Then, the measured length of the wetted portion of the tape 25B is verified with the liquid level value measured by the liquid level indica- tor FLI.

(2) The short tube portion 21 mounted between the under portion of the liquid level indicator FLI and the nozzle portion 23 of the tank T has formed therethrough an opening into which a bar 26 for verifying is inserted. Then, the displacer 3 is lifted up by rewinding the wire 2 around the winding drum 1 to balance on the bar 26 inserted from the opening and the liquid level measured by the liquid level indicator FLI is verified with the previously-measured and recorded height from the bottom TB of the tank T to the opening into which the bar 26 is inserted.

B. In case of tank generating a high pressure Since the short tube portion 21 is full of gas, the opening for accepting the bar 26 can not be formed through the short tube portion 21. For this reason, the valve (sluice valve) 22 is provided between the lower portion of the short tube portion 21 and the nozzle portion 23 of the tank T as shown in Fig. 1 A. After the partition plate 22A of the valve 22 is opened and the displacer 3 is lifted up on the partition plate 22A of the valve 22, the partition plate 22A of the valve 22 is closed and the displacer 3 is balanced on the partition plate 22A of the valve 22. Then, the liquid level value measured by the liquid level indica- tor FU is verified with the previously-measured and recorded height from the bottom TB of the tank T to the partition plate 22A of the valve 22.

C. When the liquid level indicator FLI is formed as a displacer type (self-balancing, type) one regardless of whether the tank T produces high pressure or not, a tension to be applied to the measuring wire (made of wire or tape) 2 to balance the displacer 3 on the liquid level LL is decreased and the displacer 3 is sunk into the liquid L and balanced on the bottom TB of the tank T. Then, the liquid level value measured by the liquid level indica65 level value measured by the level indicator FLI 130 tor FLI is verified with the previously-recorded 2 GB2195182A 2 value (zero value).

D. Regardless of whether the tank T produces high pressure or not, as shown in Fig. 1 B, the displacer 3 is lifted upwards and is contacted with a contact portion 27, which is formed within the short tube portion 2 1, at its upper portion. Then, the measured value is verified with the previously-measured and recorded height from the bottom TB of the tank T to 75 the contact portion 27.

Further, in the displacer type liquid level in dicator FLI, the short tube portion 21 having formed on its side wall an opening portion or nozzle 2 1 B with a lid 2 1 A is always attached 80 to the lower portion of the liquid level indica tor FLI to carry out the maintenance works such as to attach the displacer 3 to or detach the same from the free end of the wire 2.

The above mentioned conventional methods 85 for verifying the liquid level measured by the liquid level indicator FLI have the following de fects.

The method A (1) needs troublesome works and can not be effected when the liquid level indicator FLI is applied to the tank T which produces high pressure.

The method A (2) requires the short tube portion 21 which has formed at its side an opening into which the bar 26 is inserted.

This short tube portion 21 raises the manufac turing cost of the liquid level indicator FLI. At the same time, since the liquid level indicator FLI and the short tube portion 21 are gener ally connected through flanges, namely in the 100 way of a so-called flange connection as shown in Fig. 1, the height of the liquid level indicator FLI is increased. Also this method A (2) can not be effected for the tank T which produces high pressure.

The method B requires the short tube por tion 21 beneath the liquid level indicator FLI and the valve 22 under the short tube portion 21 and forms a three-story construction. This causes the height of the liquid level indicator FLI to be increased and also the manufacturing cost to be increased.

The method C can not avoid an error due to the contraction and expansion of the measur ing wire 2 in the liquid L since the tempera- 115 ture of the liquid L is not always normal and lacks in accuracy.

The method D must detect that the measuring wire 2 is weighted by a weight heavier than the weight of the displacer 3 unlike the method which measures the distance (height) by balancing the forces. Thus, the method D needs a special detecting apparatus therefor, separately.

Further, since the conventional displacer 125 type liquid level indicator FLI is provided with the short tube portion 21 having the nozzle portion 21B connected thereto in the way of flange connection, the cost of the liquid level indicator FLI is increased and the height 130 thereof is also increased so that the liquid level indicator FLI can not be made compact in size.

OBJECTS AND SUMMARY OF THE INVENTION

Accordingly, it is an object of this invention to provide an improved displacer type liquid level indicator.

It is another object of this invention to pro- vide a displacer type liquid level indicator which does not require a short tube portion having connected on its side wall a nozzle portion so that this displacer type liquid level indicator can be decreased in manufacturing cost and in height.

It is a further object of this invention to provide a displacer type liquid level indicator which can verify the measured value accurately.

It is yet further object of this invention to provide a displacer type liquid level indicator which can be applied to any tanks regardless of whether the tank produces high pressure or not.

According to one aspect of the present in vention, there is provided a displacer type liquid level indicator comprising:

a) a wire winding drum; b) a wire wound around and/or rewound from said wire winding drum; c) a displacer connected to a free end of said wire and freely moved up and down in accordance with a liquid surface to be mea sured; d) a wire winding drum housing compart ment for housing therein said wire winding drum or the like; e) at least one opening formed through a side wall of a lower portion of said wire winding drum housing compartment; and f) a lid attached to said opening.

These and other objects, features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments that are to be read in conjunction with the accompanying drawings, throughout which like reference numerals identify like elements and parts.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1A is a partly cut-away perspective view of a conventional displacer type liquid level indicator to which the present invention is applied; Fig. 113 is a partly cut-away perspective view showing a part of Fig. 1 A; Fig. 2 is a perspective view illustrating the whole of an embodiment of a displacer type liquid level indicator according to the present invention; Fig. 3 is an enlarged perspective view illustrating a portion of the displacer type liquid level indicator according to the invention shown in Fig. 2; and 3 GB2195182A 3 Fig. 4 is an enlarged perspective view of a portion of another embodiment of the displacer type liquid level indicator according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described in detail with reference to the drawings.

Fig. 2 is a perspective view illustrating the whole of an embodiment of a displacer type liquid level indicator FLI according to the pre sent invention and Fig. 3 is an enlarged per spective view illustrating a portion of Fig. 2.

Throughout Figs. 2 and 3, like parts corre sponding to those of Figs. 1 A and 1 B are marked with the same references and will not be described in detail.

The arrangement of the displacer type liquid level indicator FLI according to the present in vention for detecting the liquid surface or level is well known and therefore need not be de scribed in detail.

Referring to Fig. 2, there are shown the winding drum 1, the wire 2 wound around the 90 winding drum 1, the float or displacer 3 con nected to the free end of the wire 2 so as to be freely movable in the up and down direc tion and the winding drum housing compart ment portion 4 which incoporates therein the 95 winding drum 1 and so on, similarly to the prior art. As illustrated in Fig. 2, the winding drum housing compartment portion 4 is formed of the horizontal tube portion 4A and the vertical tube portion 4B which is coupled 100 to the horizontal tube portion 4A in perpendi cular, or in an L-shaped fashion. Openings 5 and 6 are respectively formed through the ver tical tube portion 4B in an opposing relation to each other with respect to the central axis 105 of the vertical tube portion 4B. The openings and 6 are respectively closed by lids 7A and 7B each having a transparent window, as described later. If necessary, the lids 7A and 7B are respectively reinforced by blind lids 8A 110 and 8B each having no window portion, as will be described later. Small screws (small bolts) 9A and 9B and large screws 10A and 10B are each used to fasten the lids 7A, 8A and 7B, 8B to the openings 5 and 6, respec tively.

The liquid level indicator FLI shown in Fig. 2 is mounted on or fixed to the upper portion or the nozzle portion 23 of the tank T (Fig. 1 A) through t, he flange 4C provided at the opening end portion of the tube portion 4B by using bolts (not shown) similarly to the prior art.

The operation of this liquid level indicator FLI will be described next. The wire 2 is rewound from the winding drum 1 to float the 125 displacer 3 on the liquid level or surface LL of the liquid L within the tank T, whereby the height up to the liquid surface (liquid level) LL of the liquid L from the bottom TB of the tank T is measured. The measured value can be 130 read out through an indication window portion 11 located on the panel portion of one end of the horizontal tube portion 4A. Such operations of this liquid level indicator FLI em- ployed in the invention is similar to that of the known liquid level indicator so that the detailed description thereof will be omitted for simplicity.

According to the present invention, as de- scribed above, the pair of openings 5 and 6 formed through the side wall of the vertical tube portion 413 of the drum housing compartment portion 4 are opposed to each other, or located horizontally on the same position so as to enable the user to see the displacer 3 which is moving up and down within the vertical tube portion 413 from both sides of the tube portion 4B. At the same time, at least one of the openings 5 and 6 is formed large enough in size to attach to or detach the displacer 3 from the wire 2 therethrough. Although the openings 5 and 6 are formed the same in size in the embodiment shown in Fig. 2, this will be sufficient, too. On the peripheral edges of the openings 5 and 6, there are bored four large tapped holes 12A and 12B with an equal angular distance and four small tapped holes 13A and 13B with an equal angular distance and between adjacent large tapped holes 12A and 1213.

As shown in Fig. 3, the lids 7A and 713 are respectively formed of the metal rings 7A1 and 713 '1 made of iron and the like with central opening 7A2 and 7B2 into which respectively embedded are circular transparent plates 7A3 and 7B3 and scale marks 7A4 and 7B4 are engraved or printed on the transparent plates 7A3 and 7133, respectively. In the scale marks 7A4 and 7134, reference numerals 7A5 and 7B5 respectively designate base lines, and the metal rings 7A1 and 7B1 are respectively fixed to the openings 5 and 6 such that the base lines 7A5 and 7B5 are located at the same level from, for example, the bottom TB of the tank T. On the peripheral portions of the metal rings 7A 'I and 7131, there are formed 4 large and 4 small tapped holes 14A, 14B and 15A, 15B corresponding to the tapped holes 12A, 12B and 13A, 1313, formed around the openings 5 and 6, respectively.

As shown in Fig. 2, the transparent window lids 7A and 713 are fixed to close the openings 5 and 6 by screwing the small screws 9A and 913 into the small tapped holes 13A and 1313, respectively. As described above, the lids 8A, 813 are respectively blind lids and are provided at their peripheral edges with four large tapped holes 16A and 16B corresponding to the tapped holes 12A and 1213. When the large screws (bolts) 10A and 10B are screwed into the large tapped holes 12A and 12B through tapped holes 16A and 16B of the blind lids 8A and 813 and the tapped holes 14A and 14B of the transparent win- 4 dow lids 7A and 7B, the blind lids 8A and 813 and the transparent window lids 7A and 713 are fixed to peripheral edges of the openings 5 and 6, respectively, for the reinforcement.

The blind lids 8A, 813 may not be provided if the tank T which contains the liquid L of which the liquid level LL is to be measured does not produce high pressure. If on the other hand the tank T produces high pressure, the blind lids 8A, 813 must be provided and - also the sluice valve 22 must be provided between the liquid level indicator FLI and the opening or nozzle portion 23 of the tank T similarly to the prior art, as shown in Fig. 1 A.

When checking (verifying) the level value measured by the liquid level indicator FLI of the present invention, if there are provided no blind lids 8A and 813, the displacer 3 is lifted upwards from the liquid level or surface LL and stopped at the position of the openings 5 85 and 6 as shown in Fig. 2 by the broken lines.

In this case, since the heights from the bot tom TB of the tank T to the respective lines of scale marks 7A4 and 7B4 are indicated, the position of the displacer 3 at that time can be read out from the scale marks 7A4 and 7134. Thus, the value read from the scale marks 7A4 and 7B4 is verified with the value measured and indicated by the liquid' level indi cator FLI. At that time, if two lids 7A and 713 with transparent window plates 7A3 and 7B3 on which the scale marks 7A4 and 7B4 are formed respectively are provided in opposing relation to each other as shown in Fig. 2, both of the scale marks 7A4 and 7B4 can be seen through the displacer 3 so that the above verification becomes more accurate.

In case the liquid level indicator FLI of the invention is applied to the tank T which pro duces high pressure, the valve 22 is opened, the displacer 3 is lifted upwards as described above and then the valve 22 is closed. There after, the blind lids 8A and 813 are both re moved and then the verification is carried out similary as described hereinabove.

While there are provided two openings 5 and 6 in the embodiment of the present in vention as described above_, one opening may be sufficient.

Fig. 4 is an enlarged perspective view illustrating a main portion of another embodiment of the present invention, namely, Fig. 4 illustrates lids 7a and 7b having rectangularshaped openings 7al and 7bl to be respectively attached to the openings 5 and 6 instead of the lids 7A and 713 with the transparent windows. The recta ngular-shaped openings 7a 'I and 7b 'I are formed through the central portions of the lids 7a and 7b so as to accept the bar 26. If such lids 7a and 7b are respectively attached to the openings 5 and 6 in such a fashion that the rectangular-shaped openings 7al and 7bl thereof are opposed to each other on the same horizontal line, the more accurate verification of the value indiGB2195182A 4 cated by the liquid level indicator FLI is made possible, in addition to the examination of the function of the balance system in the liquid level indicator FLI. To be more concrete, after the displacer 3 is lifted upwards over the rectangular-shaped openings 7al and 7bl of the lids 7a and 7b, the bar 26 is inserted into the rectangular-shaped openings 7al and 7bl and the displacer 3 is balanced on the bar 26.

Then, the liquid level value measured and indicated by the liquid level indicator FLI is verified with the previously measured and recorded height from the bottom TB of the tank T to the rectangular-shaped openings 7al and 7bl.

If the liquid level indicator FLI of the invention is applied to the tank T which does not produce high pressure, it is sufficient to provide only the lids 7a and 7b.

Whereas, if the liquid level indicator FLI is applied to the tank T which produces high pressure, when the verification is not necessary, the blind lids 8A and 8B must be respectively attached to the lids 7a and 7b similarly as described before in regard to Fig. 2, or the lids 7a and 7b are removed but in stead, only the blind lids 8A and 8B may be respectively attached to the openings 5 and 6.

As seen in Fig. 4, four large tapped holes 17A, 17B and four small tapped holes 18A, 18B are respectively formed through the per ipheral edge portion of the lids 7a and 7b.

The small tapped holes 18A and 18B are adapted to accept pins (not shown) which are implanted on the peripheral edge portions of.the openings 5 and 6 to locate the lids 7a and 7b at proper positions when the lids 7a and 7b are respectively fixed to the openings 5 and 6 by inserting the bolts 10A and 10B (Fig. 2) through the large tapped holes 17A and 17B. In order to determine the proper positions of the transparent window lids 7A and 7B or the lids 7a and 7b each of which has a reference on verification, it is possible to employ other positioning means such as engaging means and the like, in addition to the positioning means appeared in Figs. 2 and 4.

When only the blind lids 8A and 8B are respectively attached to the openings 5 and 6, the verification of the liquid level value measured and indicated by the liquid level indicator FLI can not be confirmed but this becomes useful for the maintenance works of the dis- placer 3 and the wire 2.

According to the present invention, as set forth above, since the openings are formed at the side walls of the lower or vertical tube portion of the liquid level indicator so as to verify the liquid level value measured by the liquid level indicator or to carry out the maintenance work of the displacer and so on, the tube portion with the nozzle portion used in the prior art becomes unnecessary. This re- duces the manufacturing cost of the liquid 1 \1 1 GB2195182A 5 level indicator and decreases the height of the liquid level indicator so that the liquid level indicator of the invention can be made compact in size.

Further, since the verification (comparison) of the liquid level value measured by the liquid level indicator with the measured reference value can be carried out at the upper portion of the tank, the verification of the measured value can be prevented from being affected by the contraction and expansion of the wire in the liquid due to the change of temperature of the liquid within the tank, so that the verification becomes accurate.

Furthermore, when the liquid level indicator of the present invention is applied to the tank which does not produce high pressure, the blind lids may be omitted, whereas when it is applied to the tank which produces high pres- sure, it is sufficient that in addition to the provision of the sluice valve, the blind lids are attached to the openings. Accordingly, the liquid level indicator of the invention can be applied to the tank regardless of whether the tank produces high pressure or not.

In addition, unlike the conventional method D as earlier noted, the liquid level indicator of the invention does not require a special detecting apparatus for detecting whether or not the wire is weighted by a weight heavier than the displacer.

The above description is given on the preferred embodiments of the invention but it will be apparent that many modifications and vari- ations could be effected by one skilled in the art without departing from the spirits or scope of the novel concepts of the invention so that the scope of the invention should be determined by the appended claims only.

Claims

1. A displacer type liquid level indicator comprising:

a) a wire winding drum; b) a wire wound around and/or rewound from said wire winding drum; c) a displacer connected to a free end of said wire and freely moved up and down in accordance with a liquid surface to be measured; d) a wire winding drum housing compartment for housing therein said wire winding drum or the like; e) at least one opening formed through a side wall of a lower portion of said wire winding drum housing compartment; and f) a lid attached to said opening.

2. A displacer type liquid level indicator according to claim 1, wherein said wire winding drum housing compartment is formed of a substantially horizontal tube portion and a substantially vertical tube portion which are coupled to each other in an L-shaped fashion.

3. A displacer type liquid level indicator ac- cording to claim 2, wherein said at least one opening is formed throuch a side wall of said substantially vertical tube portion through which said wire is extended.

4. A displacer type liquid level indicator ac- cording to claim 1, wherein said lid has a transparent window plate.

5. A displacer type liquid level indicator according to claim 4, wherein said transparent window plate of said lid has formed thereon a scale mark.

6. A displacer type liquid level indicator according to claim 1, wherein said lid having an opening is to verify the liquid level value measured by said liquid level indicator with a ref- erence value.

7. A displacer type liquid level indicator according to claim 6, wherein a bar is inserted into said verifying opening of said lid.

8. A displacer type liquid level indicator ac- cording to claim 6, wherein said verifying opening of said lid is rectangular in shape.

9. A displacer type liquid level indicator according to claim 3 or 6 further comprising a blind lid which is attached to said lid having a transparent window plate or verifying opening.

10. A displacer type liquid level indicator according to claim 2, wherein said wire drum housing compartment has formed through its vertical tube portion two openings in opposing relation to each other.

11. A displacer type liquid level indicator according to claim 1, wherein a size of said at least one opening is so selected that maintenance of said wire and displacer is possible 100 through said at least one opening.

12. A displacer type liquid level detector substantially as herein described with reference to Figures 2 and 3 or Figure 4 of the accompanying drawings.

Published 1988 at The Patent Office, State House, 66/71 High Holborn, London WC 1 R 4TP. Further copies may be obtained from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Burgess & Son (Abingdon) Ltd. Con. 1/87.