A device for measuring the linear expansion of refractory material samples by heating

Abstract

The present invention relates to a device for measuring the heating linear expansion of a refractory material sample, comprising a heating furnace, an outer cover tube, an inner push rod, an outer cover tube fixing frame, an inner push rod fixing frame, a precision linear bearing, a thermocouple, a displacement measuring device and a micro-pressure tracking mechanism. The beneficial effects are: the device of the invention has a simple structure, is easy to use, has high measurement accuracy, can accurately measure the thermal expansion performance of refractory materials during heating, and provides reliable technical parameters for the furnace body design of industrial kilns.

Description

Technical Field

[0001] The invention relates to the technical field of material performance testing, in particular to a device for measuring the heating linear expansion of a refractory material sample. Background Art

[0002] The size or volume of all materials will reversibly increase or decrease with the rise and fall of temperature within a certain temperature range. This "thermal expansion and contraction" phenomenon is a basic property of the material. The expansion / contraction of refractory materials used at high temperatures during heating or cooling is very significant, so only by accurately knowing the amount of expansion / contraction at each temperature can they be used correctly. There are many types of refractory materials with complex compositions. During the heating process, due to reversible phase changes and other reasons, the change of their dimensions with temperature is mostly nonlinear. Precision measuring instruments are required to measure the expansion at each temperature in real time. At present, the measurement of thermal (linear) expansion of refractory materials basically uses a method in which a mandrel tracks the expansion and contraction of the sample and the expansion value of the standard sample is used as a reference to assign a value. Commonly used thermal expansion coefficient testers are of two types: horizontal and vertical, and the following disadvantages are common:

[0003] 1) The tracking of the expansion and contraction of the specimen by the ejector rod basically depends on the spring or cannot be completely separated from the spring. The tracking pressure of the ejector rod on the specimen is generally large and not constant, which causes the expansion of the specimen to be affected by stress;

[0004] 2) The top rod of the horizontal thermal expansion measuring instrument is affected by the cantilever force, and the linearity of the displacement direction when tracking the expansion / contraction of the sample is poor;

[0005] 3) Most of the ejector pins of the vertical thermal expansion measuring instrument are in a free state, and the linearity in the displacement direction during the test is poor;

[0006] 4) The displacement sensor of the vertical thermal expansion measuring instrument is located above the heating furnace, and the connecting device needs to be cooled, otherwise it cannot be accurately measured;

[0007] 5) Due to the limitation of the structure itself, the diameter of the push rod of the existing thermal expansion measuring instrument is relatively thin, and the push rod needs to be made of very high-purity material to ensure that it will not deform at high temperatures. Summary of the invention

[0008] In order to overcome the defects of the prior art, the technical problem solved by the present invention is to provide a refractory material sample heating linear expansion measuring device, which has a simple structure, is easy to use, has high measurement accuracy, can accurately measure the thermal expansion performance of the refractory material during the heating process, and provide reliable technical parameters for the furnace body design of industrial kilns.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A device for measuring the linear expansion of a refractory material sample during heating, comprising a heating furnace, an outer cover tube, an inner push rod, an outer cover tube fixing frame, an inner push rod fixing frame, a precision linear bearing, a thermocouple, a displacement measuring device and a micro-pressure tracking mechanism, characterized in that the heating furnace consists of a fixed furnace body, a movable furnace body and a heating body, wherein the movable furnace body and the fixed furnace body are arranged in an upper and lower buckled arrangement, and the heating body is arranged on the movable furnace body; the outer cover tube is a cylindrical sleeve structure with a sealed upper portion, the lower portion is fixed to the fixed furnace body of the heating furnace by an outer cover tube fixing frame, and the upper portion is vertically erected in a free state in the movable furnace body of the heating furnace, and rectangular sample holes are symmetrically opened on both sides of the outer cover tube near the top, and the thermocouple can extend into the outer cover tube from one side of the sample hole; the inner push rod is a sealed platform at the upper portion shaped circular tube structure, the lower part is fixedly connected to the displacement measurement device through the inner push rod fixing frame, and the upper part is vertically erected in the outer cover tube in a free state; the outer sleeve of the precision linear bearing is fixedly connected to the outer cover tube fixing frame, and the inner sleeve is fixedly connected to the inner push rod fixing frame; the displacement measurement device is composed of an outer shell, a differential inner rod, and a displacement meter, wherein the outer shell is fixedly connected to the inner push rod fixing frame, the differential inner rod and the displacement meter are an integrated structure arranged in the inner hole of the outer shell and fixedly connected to the outer shell, and the differential inner rod is fixedly connected to the outer cover tube fixing frame; the micro-pressure tracking mechanism is composed of a weight, a wire rope and a fixed pulley, wherein the fixed pulleys are two symmetrically fixed on the outer cover tube fixing frame, and the weights are two respectively connected by wire ropes through the fixed pulleys and fixedly connected to the outer shell.

[0011] The inner push rod fixing frame is a hollow boss-shaped structure, with an inner push rod mounting socket provided at the upper part and a notch matched with the through rod provided at the lower part of the outer cover tube fixing frame at the lower part.

[0012] The differential inner rod is connected to the lower through rod of the outer cover tube fixing frame through a connecting hole, and the outer shell is connected to the inner push rod fixing frame, so that the outer cover tube fixing frame and the inner push rod fixing frame form an inner-outer reversed and buckled connecting mechanism.

[0013] The sum of the masses of the two weights is 10 to 100 g greater than the sum of the masses of the inner push rod, the inner push rod fixing frame, and the displacement measurement device.

[0014] The outer cover tube and the inner push rod are both made of high-purity corundum or fused quartz.

[0015] The displacement meter is a digital micrometer or a multimeter, which can output a displacement measurement signal to a computer.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1) The heating furnace body is divided into two parts: "fixed" and "mobile". The mobile part can be lifted up when loading samples, which is convenient for placing samples. In addition, multiple sets of measuring devices can be installed in one heating furnace at the same time to test multiple samples at one time;

[0018] 2) The displacement meter is installed under the heating furnace to avoid the high-temperature hot air flow and heat radiation generated by the heating furnace during the test. Even without cooling, the measurement accuracy of the displacement meter can be guaranteed;

[0019] 3) The precision linear bearing installed between the outer cover tube fixing frame and the inner ejector rod fixing frame can ensure that the linearity deviation of the relative movement between the inner ejector rod and the outer cover tube is extremely small during the test, thereby improving the measurement accuracy of the thermal (linear) expansion of the sample;

[0020] 4) The differential inner rod is connected to the outer cover tube fixing frame, and the displacement measuring meter is connected to the inner push rod. The inner and outer reverse interlocking connection mechanism has the following advantages: first, the displacement of the inner push rod in the non-test state can be limited to a certain safe range; second, it is convenient to use the inner push rod with a larger diameter (≥16mm), which can avoid the high temperature deformation caused by the inner push rod with a smaller diameter (about 8mm) used in the previous measuring device; third, it is convenient for the safe disassembly and maintenance of the outer cover tube and the inner push rod;

[0021] 5) The displacement meter itself does not contain an automatic reset spring. The weight, wire rope and fixed pulley form a dynamic uninterrupted tracking mechanism for the thermal (linear) expansion / contraction of the sample. The tracking force applied to the sample is constant and small, which can avoid the influence of large spring tracking stress and variable pressure on the expansion / contraction of the sample, thereby improving the measurement accuracy; at the same time, it can avoid high temperature stress deformation of the outer cover tube / inner push rod;

[0022] 6) The displacement meter uses a digital micrometer or a multimeter, the displacement measurement graduation value can reach 0.1μm, and the displacement measurement signal can be directly output to the computer. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structural principle of the present invention;

[0024] Figure 2 It is a three-dimensional structural enlarged schematic diagram of the connection relationship between the outer cover tube fixing frame, the inner push rod fixing frame and the outer shell of the displacement measuring device of the present invention.

[0025] In the figure: 1-sample 2-sample loading hole 3-outer cover tube 4-inner push rod 5-outer cover tube fixing frame 51-connecting hole 52-through rod 6-inner push rod fixing frame 61-inner push rod installation socket 62-slot 7-weight 8-housing 81-inner hole 9-differential inner rod 10-precision linear bearing 11-fixed pulley 12-fixed furnace body 13-thermocouple 14-movable furnace body 15-heating body 16-displacement measuring meter DETAILED DESCRIPTION

[0026] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0027] See Figure 1 , Figure 2 As shown, the present invention relates to a refractory material sample heating linear expansion measuring device, comprising a heating furnace, an outer cover tube 3, an inner push rod 4, an outer cover tube fixing frame 5, an inner push rod fixing frame 6, a precision linear bearing 10, a thermocouple 13, a displacement measuring device and a micro-pressure tracking mechanism, wherein the heating furnace is composed of a fixed furnace body 12, a movable furnace body 14 and a heating body 15, wherein the movable furnace body 14 and the fixed furnace body 12 are arranged in an upper and lower buckle-mounted manner, and the heating body 15 is arranged on the movable furnace body 14; the outer cover tube 3 is a cylindrical sleeve structure with a sealed upper portion, the lower portion is fixed to the fixed furnace body 12 of the heating furnace through the outer cover tube fixing frame 5, and the upper portion is vertically erected in the movable furnace body 14 of the heating furnace in a free state, and rectangular sample holes 2 are symmetrically opened on both sides of the outer cover tube 3 near the top, and the thermocouple 13 can extend into the outer cover tube 3 from one side of the sample hole 2 to measure the ambient temperature of the sample; the inner push rod 4 is a circular tube structure with a sealed platform-shaped upper portion (the platform is used to place the sample 1) , the lower part is fixedly connected to the displacement measurement device through the inner push rod fixing frame 6, and the upper part is vertically erected in the outer cover tube 3 in a free state; the outer sleeve of the precision linear bearing 10 is fixedly connected to the outer cover tube fixing frame 5, and the inner sleeve is fixedly connected to the inner push rod fixing frame 6, so that the inner push rod 4 and the outer cover tube 3 can only slide relative linearly in the vertical direction under the constraint of the precision linear bearing 10; the displacement measuring device is composed of an outer shell 8, a differential inner rod 9, and a displacement meter 16, wherein the outer shell 8 is fixedly connected to the inner push rod fixing frame 6, the differential inner rod 9 and the displacement meter 16 are arranged in the inner hole 81 of the outer shell 8 as an integral structure and are fixedly connected to the outer shell 8, and the differential inner rod 9 is fixedly connected to the outer cover tube fixing frame 5; the micro-pressure tracking mechanism is composed of a weight 7, a wire rope and a fixed pulley 11, wherein the fixed pulley 11 is two symmetrically fixed on the outer cover tube fixing frame 5, and the weight 7 is two respectively connected by wire ropes through the fixed pulley 11 and fixedly connected to the outer shell 8.

[0028] The inner push rod fixing frame 6 is a hollow boss-shaped structure, with an inner push rod mounting socket 61 provided at the upper portion and a notch 62 matched with the through rod 52 provided at the lower portion of the outer cover tube fixing frame 5 at the lower portion.

[0029] The differential inner rod 9 is connected to the lower through rod 52 of the outer cover tube fixing frame 5 through the connecting hole 51, and the outer shell 8 is connected to the inner push rod fixing frame 6, so that the outer cover tube fixing frame 5 and the inner push rod fixing frame 6 form an inside-outside reversed interlocking connection mechanism, and the relative displacement of the inner push rod 4 and the outer cover tube 3 is measured and recorded by the displacement measuring device; the outer cover tube fixing frame 5 and the inner push rod fixing frame 6 can be removed from the furnace bottom shell, which is convenient for the replacement or maintenance of the outer cover tube 3 and the inner push rod 4.

[0030] The displacement measuring device itself does not contain an automatic reset spring. Its uninterrupted tracking measurement of the thermal (linear) expansion / contraction of the sample 1 completely relies on the micro-pressure tracking mechanism composed of a weight 7, a steel wire rope and a fixed pulley 11. The sum of the masses of the two weights 7 in the micro-pressure tracking mechanism is slightly larger than the mass of the inner push rod 4, the inner push rod fixing frame 6 and the displacement measurement device assembly, and can apply a constant upward force to the inner push rod 4, the inner push rod fixing frame 6 and the displacement measurement device.

[0031] The outer cover tube 3 and the inner push rod 4 are both made of high-purity corundum or fused quartz.

[0032] The displacement meter 16 is a digital micrometer or a multimeter, which can output a displacement measurement signal to a computer.

[0033] When working, the operation steps are as follows:

[0034] 1) Make the refractory material into a sample 1 of the shape and size specified by the standard;

[0035] 2) lifting the heating furnace to move the furnace body 14 to expose the sample loading area;

[0036] 3) Place a weight with the same mass as the sample 1 and a weight slightly larger than the sample 1 (10g to 100g larger than the sample mass) on the inner push rod 4 in sequence, and select and set the mass of the weight 7 (the principle is that by adjusting the mass of the weight 7, the upward resilience of the inner push rod 4 can maintain continuous tracking of the linear expansion / contraction of the sample 1, but the tracking pressure should be as small as possible);

[0037] 4) Place the sample 1 vertically between the inner push rod 4 and the outer cover tube 3, so that both end surfaces of the sample 1 are in close contact with the inner push rod 4 and the outer cover tube 3;

[0038] 5) Lower the movable furnace body 14 of the heating furnace so that it is closed with the fixed furnace body 12 of the heating furnace, and adjust the insertion depth of the thermocouple 13 so that its hot end is close to the sample 1;

[0039] 6) The sample 1 is heated at a certain heating rate, and the linear expansion / contraction of the sample 1 at different temperatures, that is, the relative displacement of the inner push rod 4 and the outer cover tube 3, is measured and recorded by the displacement measuring device, and transmitted to the computer in real time for storage. The heating is stopped after the set heating program is completed;

[0040] 7) Based on the test data, draw a temperature-specimen thermal linear expansion / contraction rate curve or give the sample thermal linear expansion rate / expansion coefficient value at the corresponding temperature.

[0041] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A refractory material sample heating linear expansion measuring device, comprising a heating furnace, an outer cover tube, an inner push rod, an outer cover tube fixing frame, an inner push rod fixing frame, a precision linear bearing, a thermocouple, a displacement measuring device and a micro-pressure tracking mechanism, characterized in that: The heating furnace consists of a fixed furnace body, a movable furnace body and a heating body, wherein the movable furnace body and the fixed furnace body are arranged in an upper and lower buckled manner, and the heating body is arranged on the movable furnace body; the outer cover tube is a cylindrical sleeve structure with a sealed upper portion, and the lower portion is fixed to the fixed furnace body of the heating furnace through an outer cover tube fixing frame, and the upper portion is vertically erected in a free state in the movable furnace body of the heating furnace, and rectangular sample holes are symmetrically opened on both sides of the outer cover tube near the top, and the thermocouple can extend into the outer cover tube from the sample hole on one side; the inner push rod is a circular tube structure with a sealed platform shape on the upper portion, and the lower portion is fixedly connected to the displacement measurement device through an inner push rod fixing frame, and the upper portion is vertically erected in a free state The outer sleeve of the precision linear bearing is fixedly connected to the outer sleeve fixing frame, and the inner sleeve is fixedly connected to the inner push rod fixing frame; the displacement measuring device is composed of an outer shell, a differential inner rod, and a displacement meter, wherein the outer shell is fixedly connected to the inner push rod fixing frame, the differential inner rod and the displacement meter are arranged in the inner hole of the outer shell as an integrated structure and are fixedly connected to the outer shell, and the differential inner rod is fixedly connected to the outer sleeve fixing frame; the micro-pressure tracking mechanism is composed of a weight, a wire rope and a fixed pulley, wherein the fixed pulleys are two symmetrically fixed on the outer sleeve fixing frame, and the weights are two respectively connected by wire ropes through the fixed pulleys and fixedly connected to the outer shell; The inner push rod fixing frame is a hollow boss-shaped structure, with an inner push rod mounting socket provided at the upper part and a notch matched with the through rod provided at the lower part of the outer cover tube fixing frame at the lower part; The sum of the masses of the two weights is 10-100 g greater than the sum of the masses of the inner push rod, the inner push rod fixing frame, and the displacement measurement device.

2. A refractory material sample heating linear expansion measuring device according to claim 1, characterized in that: The differential inner rod is connected to the lower through rod of the outer cover tube fixing frame through a connecting hole, and the outer shell is connected to the inner push rod fixing frame.

3. The device for measuring the heating linear expansion of a refractory material sample according to claim 1, characterized in that: The outer cover tube and the inner push rod are both made of high-purity corundum or fused quartz.

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