Oil level monitoring device of oil conservator, using method and oil conservator

Abstract

The invention belongs to the technical field of oil level monitoring of transformer oil conservators, and discloses an oil level monitoring device of an oil conservator, a using method and the oil conservator, the monitoring device comprises a corrugated core body arranged in the oil conservator, a monitoring stand pipe is arranged beside the corrugated core body, the edge of the top of the corrugated core body is connected with a magnetic ring, and the magnetic ring is arranged outside the monitoring stand pipe in a sleeving mode; a monitoring circuit is arranged in the monitoring riser and comprises a power supply, a resistor string and a magnetically controlled switch, one end of the resistor string is connected with the power supply, and the other end is connected with an output end; the resistor string comprises a plurality of resistors which are connected in series; the output end of each resistor is connected with the output end through a magnetically controlled switch; the magnetic control switches are arranged at different heights in the monitoring vertical pipe in the vertical direction. The output end is connected with a resistance measuring device. The technical problem that oil level monitoring is inconvenient due to the fact that the oil conservator is affected by the installation height is solved, and real-time monitoring of the oil level of the corrugated inner oil type oil conservator is achieved.

Description

Technical Field

[0001] This invention belongs to the field of transformer oil level monitoring technology, specifically relating to an oil level monitoring device for an oil conservator, a method of use, and the oil conservator itself. Background Technology

[0002] Oil level monitoring devices for oil conservators are a crucial technical means to ensure the normal operation of oil conservators in oil-immersed transformers. When the oil temperature inside the transformer rises, there is a risk that the hot oil expansion may cause the conservator to deform. Conversely, when the transformer leaks oil, the oil level in the conservator continuously decreases, posing a risk of insufficient compensation from the conservator for the transformer tank's insulating oil. Currently, oil level monitoring for corrugated metal-lined oil conservators relies on a viewing window on one side of the conservator, using a red pointer to indicate the corresponding oil level. Alternatively, magnetic flip-flops can also be used to display the oil level value.

[0003] Most oil conservator tanks are installed above transformers. Due to the height, the above methods not only make real-time monitoring of oil levels difficult, but also increase the workload for on-site personnel. More importantly, they are prone to visual errors. The red pointer and magnetic flip panel mentioned above observe oil levels by changing color. However, due to external environmental factors, the paint used to distinguish colors is prone to fading or peeling, thus failing to determine the oil level.

[0004] Chinese patent publication number CN218768382U, entitled "A Magnetic Level Gauge with Proportional Data Acquisition and Alarm Holding Function," describes a magnetic level gauge with proportional data acquisition and alarm holding function housed within a corrugated core. The gauge includes a magnetic level display structure, a proportional pull strap structure, and high / low level alarm structures. The magnetic level display structure is mounted on the side wall connecting the cabinet and the corrugated core. The proportional pull strap structure includes a pull strap, a pull strap retraction guide structure, and a pull rod. The high / low level alarm structure includes an internal high-level trigger switch, an internal low-level trigger switch, and an alarm circuit structure with alarm holding function. This patent application still uses a magnetic level structure, which is easily affected by the external environment during observation, and the magnetic level itself is affected by its height. Summary of the Invention

[0005] In order to overcome the problems existing in the prior art, the purpose of this invention is to provide an oil level monitoring device, a method of use, and an oil tank. The device uses a corrugated core to drive a magnetic ring fitted on a monitoring riser to move up and down. The monitoring riser has a monitoring circuit inside, which can solve the technical problem that the current corrugated internal oil tank makes oil level monitoring inconvenient due to the influence of installation height.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides an oil level monitoring device for an oil tank, comprising: a corrugated core disposed in the oil tank; a monitoring riser disposed beside the corrugated core; a magnetic ring connected to the top edge of the corrugated core; the magnetic ring being sleeved outside the monitoring riser; a monitoring circuit disposed in the monitoring riser; the monitoring circuit comprising a power supply, a resistor string, and a magnetic switch; one end of the resistor string being connected to the power supply, and the other end being connected to an output terminal; the resistor string comprising multiple resistors connected in series; the output terminal of each resistor being connected to the output terminal via a magnetic switch; the magnetic switches being disposed at different heights along the vertical direction inside the monitoring riser; and a resistance measuring device being connected to the output terminal.

[0007] Optionally, the resistance measuring device includes a conversion circuit and a display device, with one end of the conversion circuit connected to the output terminal and the other end connected to the display device.

[0008] Optionally, the conversion circuit is an analog-to-digital converter, and the display device is a digital display.

[0009] Optionally, each resistor in the resistor string has the same resistance value.

[0010] Optionally, magnetic switches are equidistantly installed along the vertical direction inside the monitoring riser.

[0011] Optionally, a counterweight plate is provided on the top of the corrugated core, and the magnetic ring is connected to the counterweight plate.

[0012] Optionally, an extension plate is connected to the counterweight plate, and the magnetic ring is connected to the extension plate.

[0013] Optionally, the bottom of the corrugated core is connected to a base plate, and the bottom of the monitoring riser is connected to the base plate.

[0014] Secondly, the present invention provides a method for using the oil level monitoring device for an oil tank, comprising the following steps: Changes in the oil level inside the corrugated core cause changes in the height of the corrugated core, which in turn causes the magnetic coil to move up and down along the monitoring riser. When the magnetic coil reaches the position of the magnetic control switch installed in the monitoring riser, the magnetic control switch closes, and the resistance of the monitoring circuit changes. The resistance of the monitoring circuit is measured by a resistance measuring device to obtain the height information of the magnetic coil.

[0015] Thirdly, the present invention provides an internal oil storage tank, including an internal oil storage tank body and an oil level monitoring device for the oil storage tank.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses an oil level monitoring device, a method of use, and an oil tank. By using a corrugated core to drive a magnetic ring to move up and down, the invention solves the technical problem that the current corrugated internal oil tank is inconvenient for oil level monitoring due to the influence of installation height. It realizes real-time monitoring of the oil level in the corrugated internal oil tank and can adjust the sensitivity of the oil level monitoring device as needed to improve the accuracy level of the oil level monitoring device.

[0017] Furthermore, since each resistor in the resistor string of the present invention has the same resistance value, the monitoring circuit can output a linearly changing voltage, which facilitates monitoring.

[0018] Furthermore, this invention converts the output to a standard output via a conversion circuit, and finally connects a display device to the output of the conversion circuit. This not only solves the technical problem of inconvenient oil level monitoring caused by the installation height of current corrugated internal oil tanks, but also enables real-time monitoring of oil level changes. Attached Figure Description

[0019] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely schematic to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. In the drawings: Figure 1 This is a structural diagram of the oil level monitoring device for the oil tank according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the monitoring circuit structure according to an embodiment of the present invention; Figure 3 This is a topology diagram of the monitoring circuit according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the conversion circuit according to an embodiment of the present invention; Explanation of reference numerals in the attached diagram: 1. Monitoring riser; 2. Magnetic coil; 3. Outer plate; 4. Corrugated core; 5. Base plate; 6. Counterweight plate; 7. Conversion circuit; 8. Display device. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0021] Therefore, the following detailed description of embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0022] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0023] When an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments. The use of the term "horizontal" does not imply that the component is required to be absolutely horizontal, but rather that it may be slightly tilted. "Horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it may be slightly tilted.

[0024] It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification and appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0026] The present invention will now be described in detail with reference to the accompanying drawings.

[0027] like Figure 1As shown, an oil level monitoring device for an oil tank according to the present invention is characterized by comprising: a corrugated core 4 disposed in the oil tank; a monitoring riser 1 disposed beside the corrugated core 4; a magnetic ring 2 connected to the top edge of the corrugated core 4; the magnetic ring 2 being sleeved on the outside of the monitoring riser 1; a monitoring circuit in the monitoring riser 1; the monitoring circuit including a power supply, a resistor string, and a magnetic switch; one end of the resistor string being connected to the power supply, and the other end being connected to an output terminal; the resistor string consisting of multiple resistors connected in series; the output terminal of each resistor being connected to the output terminal via a magnetic switch; the magnetic switches being disposed at different heights along the vertical direction inside the monitoring riser 1; and a resistance measuring device connected to the output terminal.

[0028] The method of using the oil level monitoring device for an oil tank according to the present invention includes the following steps: The corrugated core 4 changes height with the oil level, causing the magnetic ring 2 to move up and down along the monitoring riser 1; When the magnetic coil 2 reaches the position of the magnetic control switch set in the monitoring riser 1, the magnetic control switch closes, and the resistance of the monitoring circuit changes. The resistance of the monitoring circuit is measured by a resistance measuring device to obtain the height information of the magnetic coil 2.

[0029] This invention solves the technical problem of inconvenient oil level monitoring caused by the installation height of the current corrugated internal oil tank by driving the magnetic ring 2 to move up and down through the corrugated core 4. It realizes real-time monitoring of the oil level of the corrugated internal oil tank and can change the sensitivity of the oil level monitoring device as needed to improve the accuracy level of the oil level monitoring device.

[0030] Example 1 An oil level monitoring device for an oil tank according to this embodiment includes: a corrugated core 4 disposed in the oil tank, a monitoring riser 1 disposed next to the corrugated core 4, a magnetic ring 2 connected to the top edge of the corrugated core 4, and the magnetic ring 2 being sleeved on the outside of the monitoring riser 1.

[0031] The monitoring riser 1 contains a monitoring circuit, which includes a power supply, a resistor string, and a magnetic switch. One end of the resistor string is connected to the power supply, and the other end is connected to an output terminal.

[0032] The resistor string consists of multiple resistors connected in series; the first end of the magnetic switch is connected to the circuit between two adjacent resistors, that is, the first end of the magnetic switch is electrically connected to two adjacent resistors respectively, and the second end of the magnetic switch is connected to the output terminal through a magnetic switch.

[0033] The magnetic control switch is installed at different heights along the vertical direction inside the monitoring riser 1; the output terminal is connected to a resistance measuring device.

[0034] Optionally, the monitoring riser 1 is made of hollow stainless steel.

[0035] Specifically, such as Figure 2 and 3 As shown, the monitoring circuit inside the monitoring riser 1 has n resistors, namely the first resistor R1, the second resistor R2, ..., the nth resistor Rn.

[0036] Alternatively, all resistors in the monitoring circuit have the same resistance value.

[0037] Specifically, the monitoring circuit inside the monitoring riser 1 has n magnetic switches, namely the first magnetic switch K1, the second magnetic switch K2, ..., the nth magnetic switch Kn.

[0038] Alternatively, all magnetic switches in the monitoring circuit are of the same model.

[0039] The resistance measuring device includes a conversion circuit 7 and a display device 8. One end of the conversion circuit 7 is connected to the output terminal, and the other end is connected to the display device 8.

[0040] Optionally, the conversion circuit 7 is an analog-to-digital converter, and the display device 8 is a digital display.

[0041] Optionally, all magnetic switches are normally open monostable magnetic switches, and the effective range of the magnetic coil 2 affecting the magnetic switch is no greater than the distance between two adjacent magnetic switches, preventing the simultaneous triggering of two magnetic switches. Further, the magnetic switches are reed switches.

[0042] Optionally, the magnetic switches are equidistant in height.

[0043] Furthermore, in this embodiment, the monitoring riser 1 is equipped with a magnetic switch at least at the height of the corrugated core 4 corresponding to the oil levels of 100%, 80%, 60%, 40%, 20%, and 0%.

[0044] Optionally, the output terminal is located at the bottom of the monitoring riser 1.

[0045] The monitoring circuit can output a linearly changing voltage, which can be converted into a standard 4-20mA signal output by the conversion circuit 7, realizing the real-time monitoring function of oil level changes.

[0046] The sensitivity of the oil level monitoring device in the oil tank can be improved by increasing the number of resistors and magnetic switches.

[0047] The top of the corrugated core 4 is provided with a counterweight plate 6, and the magnetic ring 2 is connected to the counterweight plate 6.

[0048] The counterweight plate 6 is connected to the extension plate 3, and the magnetic ring 2 is connected to the extension plate 3.

[0049] The extension plate 3 is a U-shaped plate, and the extension plate 3 is sleeved on the outside of the monitoring riser 1.

[0050] The bottom of the corrugated core 4 is connected to a base plate 5, and the bottom of the monitoring riser 1 is connected to the base plate 5.

[0051] Optionally, the monitoring riser 1 is perpendicular to the base plate 5.

[0052] Example 2 This embodiment provides an oil level monitoring device for an oil tank. The relationship between the change in internal volume of the oil tank and the change in oil level is shown in Formula 1. Since the cross-section s of the corrugated core in the direction of operation is basically fixed, the change in internal volume ΔV is linearly related to the change in operating stroke Δh and the change in oil level.

[0053] △V=s×△h Equation 1 In the formula, s is the cross-sectional area of ​​the corrugated core, m 2 ; △h is the change in oil level height, in meters.

[0054] An extension plate 3 is fixed on one side of the counterweight plate 6 at the top of the corrugated core 4 of the oil tank, and an O-shaped magnetic ring 2 is fixed on the extension plate 3. The monitoring circuit is fixed inside the monitoring riser 1, and the monitoring riser 1 is vertically installed on the bottom plate 5 of the oil tank. The upper end of the monitoring riser 1 is fitted into the magnetic ring 2.

[0055] Connect n resistors with the same resistance value, namely the first resistor R1, the second resistor R2, ..., the nth resistor Rn, in series. Then connect n magnetic switches, namely the first magnetic switch K1, the second magnetic switch K2, ..., the nth magnetic switch Kn, to the two ends of the first resistor R1, the second resistor R2, ..., the nth resistor Rn.

[0056] In this configuration, the power supply VCC is connected to the first resistor R1. The other end of the first resistor R1 is connected to the second resistor R2 and the first magnetic switch K1. The other end of the first magnetic switch K1 is connected to the output terminal Vout. The other end of the second resistor R2 is connected to the third resistor R3 and the second magnetic switch K2. The other end of the second magnetic switch K2 is connected to the output terminal Vout. This connection continues until the output terminal of the (n-1)th resistor Rn-1 is connected to the nth resistor Rn and the (n-1)th magnetic switch Kn-1. The second end of the nth resistor Rn is connected to the nth magnetic switch, and the other end of the nth magnetic switch is connected to the output terminal Vout.

[0057] Optionally, in this embodiment, a bottom magnetic switch K0 is provided at the height corresponding to the lowest liquid level of the corrugated core 4 in the monitoring riser 1.

[0058] Optionally, in this embodiment, the power supply VCC is connected to the first resistor R1 through a fuse resistor r. The input terminal of the fuse resistor r is connected to the output terminal of the power supply VCC. The output terminal of the fuse resistor r is connected to the input terminal of the first resistor R1 and the input terminal of the bottom magnetic switch K0. The output terminal of the bottom magnetic switch K0 is connected to the output terminal Vout.

[0059] Finally, fix the connected monitoring circuit inside the monitoring riser 1, so that the magnetic control switch K0 is in the closed state after the corrugated core 4 is evacuated, indicating that the displacement is 0, and the oil level is considered to be 0 in this state.

[0060] The position of the nth magnetic switch is the displacement H of the maximum compensation volume of the corrugated core 4. Assuming the oil level reaches 100% of full scale in this state, the formula for the current liquid level height Δh is: △h=H / n (Equation 2) When the magnetic coil 2 rises to the position of the first magnetic control switch K1, the bottom magnetic control switch is opened and the first magnetic control switch K1 is closed. At this time, except for the fuse resistor r, only the first resistor R1 is connected to both ends of the monitoring circuit.

[0061] When the magnetic coil 2 rises to the position of the second magnetic switch K2, the first magnetic switch K1 opens and the second magnetic switch K2 closes. At this time, only the first resistor R1 and the second resistor R2 are connected in series in the monitoring circuit. Similarly, when the magnetic coil 2 rises to the position of the nth magnetic switch Kn, the (n-1)th magnetic switch Kn-1 opens and Kn closes. At this time, all resistors R1, R2, ..., Rn are connected in series.

[0062] U ab =I ab ×R type 3 In the formula, R = R1 + R2 + ... + Rn Since R1, R2, ..., Rn have the same resistance value, and combining formulas 2 and 3, when the oil level in the oil tank rises, the resistance value in the monitoring circuit is proportional to the oil level in the oil tank.

[0063] In this embodiment, each resistor has the same resistance value and the same voltage across each resistor. This voltage is connected to the output terminal Vout through an engaged magnetic switch, meaning that the voltage change at the output terminal Vout is linear.

[0064] By increasing the number of resistors and magnetic switches (n), the spacing between magnetic switches K0, K1, ..., Kn can be shortened, thereby improving the sensitivity of the oil level monitoring device for the oil tank.

[0065] As one embodiment of this example, the range of the oil level monitoring device for the oil tank is 1000 mm.

[0066] When n=50, the distance Δh between each magnetic switch is 20mm. For every displacement increment, the oil level in the oil tank changes by 2%. Therefore, it is assumed that the oil level indicated by the oil level monitoring device has increased by 20mm under this condition.

[0067] When n=100, the distance Δh between each magnetic switch is 10m. For every displacement increment, the change in oil level in the oil tank is 1%. That is, under this condition, the oil level indicated by the oil level monitoring device has increased by 10mm.

[0068] When n=200, the distance Δh between each magnetic switch is 5mm. For every 1 displacement increase, the change in oil level in the oil tank is 0.5%. That is, under this condition, the oil level indicated by the oil level monitoring device has increased by 5mm.

[0069] Optionally, such as Figure 3 As shown, the end of the monitoring circuit furthest from the power supply is grounded. For example... Figure 4 As shown, the linearly changing voltage output from the circuit is converted into a standard 4-20mA output via a conversion circuit. Finally, a digital display is connected to the output of the conversion circuit to achieve real-time monitoring of oil level changes. This oil level monitoring device not only achieves real-time monitoring but also features stable and highly reliable remote signal transmission.

[0070] This invention solves the technical problem of inconvenient oil level monitoring in internal oil tanks due to the installation height, by using an oil level monitoring device for the oil tank. It enables real-time monitoring of the oil level in internal oil tanks and improves the accuracy level of the oil level monitoring device by adjusting its sensitivity as needed.

[0071] Example 4 An internal oil storage tank includes an internal oil storage tank body and an oil level monitoring device for the oil storage tank.

[0072] The internal oil storage tank body includes an internal oil storage tank shell, and a corrugated core 4 is disposed inside the internal oil storage tank shell.

[0073] Specifically, in this embodiment, the body of the internal oil storage tank is a metal corrugated internal oil vertical storage tank.

[0074] Specifically, in this embodiment, the output terminal of the monitoring circuit extends from the bottom of the monitoring riser 1 and extends from the bottom of the inner oil tank casing to the base of the tank, preventing the top from being unable to prevent rain due to the need for openings. The output terminal is then connected to the external display device 8.

[0075] Unless otherwise specified, the equipment components involved in the above embodiments are all conventional equipment components, and the structural settings, working methods or control methods involved are all conventional settings, working methods or control methods in the art unless otherwise specified.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. An oil level monitoring device for an oil reservoir, characterised in that, The application relates to an oil level monitoring device for an oil tank. The oil level monitoring device comprises a corrugated core (4) arranged in the oil tank, a monitoring vertical pipe (1) arranged beside the corrugated core (4), a magnetic ring (2) connected to the top edge of the corrugated core (4), wherein the magnetic ring (2) is sleeved outside the monitoring vertical pipe (1); a monitoring circuit arranged in the monitoring vertical pipe (1), wherein the monitoring circuit comprises a power supply, a resistance string and a magnetic control switch, one end of the resistance string is connected to the power supply, and the other end is connected to an output end; the resistance string comprises a plurality of resistors connected in series; the output end of each resistor is connected to the output end through a magnetic control switch; the magnetic control switches are arranged at different heights in the monitoring vertical pipe (1) in the vertical direction; and the output end is connected to a resistance measuring device.

2. An oil level monitoring device for an oil reservoir as claimed in claim 1, wherein The resistance measuring device comprises a conversion circuit (7) and a display device (8), one end of the conversion circuit (7) is connected to the output end, and the other end is connected to the display device (8).

3. An oil level monitoring device for an oil reservoir as claimed in claim 2, wherein The conversion circuit (7) is an analog-to-digital converter, and the display device (8) is a digital display.

4. An oil level monitoring device for an oil reservoir as claimed in claim 1, wherein The resistance values of the resistors in the resistance string are the same.

5. An oil level monitoring device for an oil reservoir as claimed in claim 1, wherein, The magnetic control switches are equidistantly arranged in the vertical direction in the monitoring vertical pipe (1).

6. An oil level monitoring device for an oil reservoir as claimed in claim 1, wherein, A counterweight plate (6) is arranged at the top of the corrugated core (4), and the magnetic ring (2) is connected to the counterweight plate (6).

7. An oil level monitoring device for an oil reservoir according to claim 6, wherein An extension plate (3) is connected to the counterweight plate (6), and the magnetic ring (2) is connected to the extension plate (3).

8. An oil level monitoring device for an oil reservoir as claimed in claim 1, wherein, A bottom plate (5) is connected to the bottom of the corrugated core (4), and the bottom of the monitoring vertical pipe (1) is connected to the bottom plate (5).

9. A method of using an oil level monitoring device for an oil reservoir according to any one of claims 1 to 8, wherein, The application further discloses an oil level monitoring method. When the oil level in the corrugated core (4) changes, the height of the corrugated core (4) changes, the magnetic ring (2) moves up and down along the monitoring vertical pipe (1) driven by the corrugated core (4); When the magnetic ring (2) reaches the position of the magnetic control switch arranged in the monitoring vertical pipe (1), the magnetic control switch is closed, and the resistance of the monitoring circuit changes; The resistance of the monitoring circuit is measured by the resistance measuring device, and the height information of the magnetic ring (2) is obtained.

10. An internal oil reservoir characterized by The oil tank body is an inner oil type oil tank body, and the oil level monitoring device is the oil level monitoring device according to any one of claims 1 to 8.

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