A calibration fixture for opacimeter filters

Abstract

The present invention provides a calibration fixture for opacimeter filters, which is used for fixing and clamping opacimeter filters of different sizes and specifications. The calibration fixture is adjustable in height and width so that it can be suitable for opacimeter filters of different specifications, and can be conveniently adjusted during the calibration process. It is fixed with a clamping structure. Combined with the calibration method, the calibration work of the opacimeter filter has a complete set of specific calibration solutions, which gets rid of the current situation of relying on the calibration procedures of the standard filters of the spectrophotometer.

Description

Technical Field

[0001] The present invention relates to the field of filter calibration, and more specifically, to a calibration fixture for clamping an opaque smoke meter filter during the calibration process of an opaque smoke meter filter. Background Art

[0002] A smoke meter is an instrument for measuring the smoke density in the exhaust gas of an automobile, mainly used for measuring the exhaust gas of a diesel engine.

[0003] Due to the advantages of being able to simultaneously measure blue smoke, white smoke, and black smoke in the exhaust gas of a diesel engine, having accurate measurement, being able to continuously measure the smoke density in the exhaust gas of a diesel engine, and reflecting the instantaneous working conditions of a diesel engine, the national standard stipulates that for diesel vehicles produced after October 1, 2001, their exhaust gas is detected using an opaque smoke meter.

[0004] Each opaque smoke meter is required to be equipped with at least 3 opaque smoke meter filters as a standard configuration when leaving the factory and provided to users, facilitating users to regularly calibrate the smoke meter to ensure the accuracy and reliability of the measurement data of the smoke meter.

[0005] Currently, there is no method and corresponding technology for the traceability of opaque smoke meter filters in China, which cannot guarantee the quantity value of the opaque smoke meter filters themselves, and further leads to the inability to judge whether the data of the smoke meter calibration and measurement are accurate and reliable.

[0006] The existing JJG 976-2010 "Verification Regulation for Transmissive Smoke Meters" in China is applicable to the calibration of opaque smoke meters; JJG 1034-2008 "Verification Regulation for Standard Filter of Spectrophotometer" is applicable to the calibration of filters for ultraviolet-visible spectrophotometers, microplate readers, etc.

[0007] Moreover, the calculation formulas for the transmittance given in the "Verification Regulation for Standard Filter of Spectrophotometer" are different from those in the "Verification Regulation for Transmissive Smoke Meters", resulting in their incompatibility.

[0008] In addition, JJF(Yu)194-2015 "Calibration Specification for Filters of Line-Type Beam Smoke Detectors" is applicable to the calibration of filters of line-type beam smoke detectors and not applicable to the calibration of opaque smoke meter filters.

[0009] The sizes of opacimeter filters vary from manufacturer to manufacturer, and do not match the universal optical detection bracket that comes standard with the spectrophotometer, so they cannot be effectively fixed. In actual work, the opacimeter filters are mainly fixed by methods such as adhesive bonding, which reduces the reproducibility of the calibration work. In addition, the process of adjusting the opacimeter filters to align with the light transmission hole is relatively complicated. A calibration fixture is needed that is compatible with opacimeter filters of different specifications from different manufacturers.

[0010] In order to solve the above problems, an ideal technical solution has been sought. Summary of the invention

[0011] The purpose of the present invention is to address the deficiencies of the prior art and thus provide a calibration fixture for opacimeter filters, which can fix and clamp opacimeter filters of different sizes and specifications, is easy to operate, simple to use, facilitates calibration and installation work by staff, and improves work efficiency.

[0012] The technical solution adopted by the present invention is:

[0013] A calibration fixture for an opacimeter filter comprises a filter fixing back plate, a filter insertion limit baffle, a filter pressing spring and a filter width limiting spring. A positioning groove for inserting an opacimeter filter is vertically arranged on the filter fixing back plate, a light-transmitting hole is provided at the bottom of the groove at the center of the positioning groove, and the filter width limiting springs are fixed in pairs on the groove walls on both sides of the positioning groove; the fixed end of the filter pressing spring is fixed to the filter fixing back plate, and the free end is suspended in the positioning groove, so as to press the opacimeter filter; the filter insertion limit baffle can be longitudinally adjusted and installed on the filter fixing back plate, and the upper end of the filter insertion limit baffle and the filter width limiting spring cooperate with the positioning groove to form a placement area for the opacimeter filter.

[0014] The filter width limiting spring piece is a spring piece with a folded angle. The fixed end of the filter width limiting spring piece is fixed to the side wall of the positioning groove by a clamping screw. The folded angle abuts against the left side or right side of the opacimeter filter. The free end is used to limit the stroke. A stroke groove is provided on the side wall of the positioning groove corresponding to the free end of the filter width limiting spring piece.

[0015] The angled protruding end of the filter width limiting spring piece faces the positioning groove, and a silicone anti-slip sleeve is provided on the filter width limiting spring piece; two pairs of filter width limiting spring pieces are arranged, respectively located on the upper and lower side walls of the positioning groove.

[0016] The fixed end of the filter pressing spring is fixed to the front side of the filter fixing back plate through a tightening bolt, and the free end of the filter pressing spring contacts the front side of the filter fixing back plate and is fixed by friction.

[0017] The filter pressing spring is composed of four sections, wherein the first section is a supporting section, which is in the shape of a flat strip and is provided with a through hole, which is inserted into the tension bolt; the second section is a transition section, which is in the shape of an arc protruding toward the front; the third section is a rib pressing section, which is in the shape of a flat strip and is used to press the front of the opacimeter filter; the fourth section is a hand-held section, which is arranged perpendicular to the filter fixing back plate, and the four sections of the filter pressing spring are integrally formed.

[0018] A silicone anti-slip sleeve is arranged on the filter pressing spring piece; a pair of filter pressing spring pieces are arranged, and are located at the upper part of the filter fixing back plate and at the left and right sides of the positioning groove.

[0019] The filter insertion limit baffle is a C-shaped structure and embraces the front side of the positioning groove. Two rows of positioning holes are arranged longitudinally on the back of the filter fixing back plate. Adjustment screw holes corresponding to the positioning holes are arranged on the left and right ends of the filter insertion limit baffle, and the adjustment bolts are passed through the adjustment screw holes to the positioning holes for fixing.

[0020] The material of the filter fixing back plate is aluminum alloy, and the surface of the filter fixing back plate is black oxidized.

[0021] The present invention has outstanding substantial features and significant progress compared with the prior art. Specifically, the present invention is adjustable in length and width directions for opacimeter filters of different sizes and specifications, has a clamping design in the front and rear directions, and realizes the positioning and fixation of the opacimeter filters in all directions. It is suitable for the calibration of opacimeter filters of various sizes. For the same opacimeter filter, the fixed position will not change easily, reducing the detection error caused by different positions during repeatability tests, getting rid of the disadvantage of fixing with adhesive tape in the prior art, making the reproducibility of the calibration of opacimeter filters easier, and the structure of the fixture is simple, the use difficulty is low, and it is easy to promote and apply. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of a calibration fixture for a light-tight smoke meter filter in the present invention;

[0023] Figure 2 yes Figure 1 A top view of

[0024] Figure 3 yes Figure 1 Rear view of

[0025] In the figure: 1. Opaque smoke meter filter; 2. Filter fixing back plate; 3. Filter insertion limit baffle; 4. Filter pressing spring; 5. Tension bolt; 6. Filter pressing spring; 7. Filter width limit spring; 8. Filter width limit spring pressing screw; 9. Light transmission hole; 10. Adjustment bolt; 11. Positioning hole; 12. Positioning slot; 13. Travel slot. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described in detail below through specific implementation methods.

[0027] like Figure 1 , Figure 2 and Figure 3 As shown, a calibration fixture for an opacimeter filter includes a filter fixing back plate 2, a filter insertion limiting baffle 3, a filter pressing spring 6 and a filter width limiting spring 7.

[0028] The filter width limiting spring pieces are fixed in pairs on the two side groove walls of the positioning groove; the fixed end of the filter pressing spring piece is fixed on the filter fixing back plate, and the free end is suspended in the positioning groove, which is used to press the opacimeter filter; the filter insertion limiting baffle can be longitudinally adjusted and installed on the filter fixing back plate, and the upper end of the filter insertion limiting baffle and the filter width limiting spring piece cooperate with the positioning groove to form a placement area for the opacimeter filter.

[0029] A positioning groove 12 for inserting the opacimeter filter is vertically arranged on the filter fixing back plate 2. The positioning groove 12 is used to accommodate the opacimeter filter 1. A light-transmitting hole 9 is arranged at the bottom of the center of the positioning groove 12. The light-transmitting hole 9 is used to pass light during calibration. The material of the filter fixing back plate 2 is aluminum alloy. Aluminum alloy is smooth, corrosion-resistant, easy to obtain, and not easy to deform after plasticization, thereby ensuring the detection positioning accuracy. Of course, other materials can also be used, such as hard plastic plates, alloy plates, etc. The surface of the filter fixing back plate 2 is black oxidized. During the implementation process, the entire device can be black oxidized. The purpose is: on the one hand, it can prevent the fixture from corroding and rusting; on the other hand, the black color can absorb other scattered light in the measuring cell, ensuring that the light can only pass through the light-transmitting hole 9, thereby achieving the uniqueness of the light path.

[0030] The filter width limiting spring pieces 7 are fixed in pairs on the groove walls on both sides of the positioning groove 12. In this embodiment, there are two pairs of filter width limiting spring pieces 7, and the fixed ends of the filter width limiting spring pieces 7 are fixed to the side walls of the positioning groove 12 through the filter width limiting spring piece clamping screws 8, and are respectively arranged on the upper and lower side walls of the positioning groove. The filter width limiting spring piece 7 is a spring piece with a folded angle, which is elastic and can be deformed and moved to a certain extent, and can be pressed inward and stretched outward. The folded angle protruding end of the filter width limiting spring piece 7 faces the inside of the positioning groove 12 (assuming that the longitudinal center line of the positioning groove is the inside), and the folded angle abuts against the left side or right side of the opacimeter filter, and the opacimeter filter is clamped and positioned by the filter width limiting spring pieces 7 arranged in pairs. The free end is used to limit the stroke, and a stroke groove 13 is provided on the side wall of the positioning groove 12 corresponding to the free end of the filter width limiting spring 7, which is used to limit the stroke range of the filter width limiting spring. At the same time, a silicone anti-slip sleeve is provided on the filter width limiting spring; the corner is more rounded, which will not cause damage to the opacimeter filter 1. The filter width limiting spring can be made of stainless steel.

[0031] In this embodiment, a pair of filter pressing springs are provided, which are located on the upper part of the filter fixing back plate 2 and on the left and right sides of the positioning groove. The fixed ends of the filter pressing springs 4 and 6 are fixed to the front side of the filter fixing back plate 2 by the tension bolts 5. The tension bolts 5 can be used to control the fixation of the filter pressing springs 4 and 6 by the tension of the bolts. The free ends are suspended in the positioning grooves 12 and are used to press the front side of the opacimeter filter (that is, the filter pressing springs 4 and 6 are pressed against the front side of the opacimeter filter). The free ends of the filter pressing springs 4 and 6 are in contact with the front side of the filter fixing back plate 2 and fixed by friction, so that after the tension bolts 5 are loosened, the filter pressing springs 4 and 6 can rotate. The tension bolts 5 can be designed as hand-tightened bolts for easy disassembly and assembly.

[0032] The filter pressing spring 4 is composed of four sections, and the four sections are integrally formed. The first section is a support section, which is in the shape of a flat strip, and is provided with a through hole, which is sleeved on the tension bolt, and the support section plays a supporting and fixing role; the second section is a transition section, which is in the shape of an arc protruding toward the front, and the function of the transition section is to apply force to the rib pressing section, and the physical force of the arc structure makes the rib pressing section more powerful when pressing the opaque smoke meter filter; the third section is a rib pressing section, which is in the shape of a flat strip, and the rib pressing section is used to press the front of the opaque smoke meter filter, so that the opaque smoke meter filter can be completely fitted with the bottom surface of the positioning groove to prevent displacement and ensure the accuracy of detection; the fourth section is a hand-held section, which is arranged perpendicular to the filter fixing back plate, and the function of the hand-held section is to facilitate the staff to rotate the filter pressing spring and to move it.

[0033] At the same time, a silicone anti-slip sleeve is provided on the filter pressing spring piece to prevent the filter pressing spring pieces 4 and 6 from scratching the opacimeter filter.

[0034] When it is necessary to insert the opacimeter filter 1, first loosen the tension bolt 5, and the staff manually pinches the handle section to rotate the filter pressing springs 4 and 6 to a vertical position or to the sides, and after inserting the opacimeter filter 1, push the filter pressing springs 4 and 6 back and tighten the tension bolt 5. When it is necessary to take out the opacimeter filter 1, the reverse steps are the same as above.

[0035] The filter insertion limit baffle 3 is a C-shaped structure and embraces the front side of the positioning groove. Two rows of positioning holes 11 are arranged in the longitudinal direction on the back of the filter fixing back plate 2. Adjustment screw holes corresponding to the positioning holes 11 are arranged at the left and right ends of the filter insertion limit baffle 3. The adjustment bolt 10 passes through the adjustment screw hole to the positioning hole 11. The filter insertion limit baffle 3 can be installed on the filter fixing back plate 2 in a longitudinally adjustable manner. The upper end of the filter insertion limit baffle 3 and the filter width limit spring 8 cooperate with the positioning groove 12 to form a placement area for the opacimeter filter.

[0036] Usage process: first loosen the tension bolt 5, push the filter pressing springs 4 and 6 to both sides, then put in the opacimeter filter 1, adjust the position of the opacimeter filter 1 corresponding to the light transmission hole 9 by adjusting the height of the filter insertion limit baffle 3, then insert the filter into the limit baffle 3 to fix it, then rotate the filter pressing springs 4 and 6 to the front side of the opacimeter filter 1, tighten the tension bolt 5 to press the opacimeter filter 1, then place the entire fixture at the measured position and start detection.

[0037] The above description is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by a person of ordinary skill in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A calibration fixture for an opacimeter filter, characterized in that: It includes a filter fixing back plate, a filter insertion limiting baffle, a filter pressing spring and a filter width limiting spring. A positioning groove for inserting a light-proof smoke meter filter is vertically arranged on the filter fixing back plate, and a light-transmitting hole is provided at the bottom of the groove at the center of the positioning groove. The filter width limiting springs are fixed in pairs on the groove walls on both sides of the positioning groove; the fixed end of the filter pressing spring is fixed to the filter fixing back plate, and the free end is suspended in the positioning groove, and is used to press the light-proof smoke meter filter; the filter insertion limiting baffle can be longitudinally adjusted and installed on the filter fixing back plate, The filter is inserted into the upper end of the limit baffle, the filter width limiting spring piece cooperates with the positioning groove to form a placement area for the opacimeter filter; the filter width limiting spring piece is a spring piece with a folded angle, and the fixed end of the filter width limiting spring piece is fixed to the side wall of the positioning groove by a clamping screw, and the folded angle abuts against the left side or right side of the opacimeter filter, and the free end is used to limit the stroke, and a stroke groove is provided on the side wall of the positioning groove corresponding to the free end of the filter width limiting spring piece; the folded angle protruding end of the filter width limiting spring piece faces the positioning groove, and the filter width limiting spring piece is provided with a silicone anti-slip sleeve sleeve; two pairs of filter width limiting spring pieces are arranged, which are respectively located on the upper and lower side walls of the positioning groove; the fixed end of the filter pressing spring piece is fixed to the front side of the filter fixing back plate through a tension bolt, and the free end of the filter pressing spring piece is in contact with the front side of the filter fixing back plate and fixed by friction; the filter pressing spring piece is composed of four sections, and the first section is a supporting section, which is in the shape of a flat strip, and a through hole is provided on the supporting section, and the through hole is sleeved on the tension bolt; the second section is a transition section, which is in the shape of an arc protruding toward the front; the third section is a rib pressing section, which is in the shape of a flat strip, and the rib pressing section is used to press The front of the opacimeter filter; the fourth section is the hand-held section, which is arranged perpendicular to the filter fixing back plate, and the four sections of the filter pressing spring are integrally formed; the filter pressing spring is provided with a silicone anti-slip sleeve; a pair of filter pressing springs are arranged, located on the upper part of the filter fixing back plate and on the left and right sides of the positioning groove; the filter insertion limit baffle is a C-shaped structure and embraces the front side of the positioning groove, and two rows of positioning holes are arranged in the longitudinal direction on the back of the filter fixing back plate, and the left and right ends of the filter insertion limit baffle are provided with adjustment screw holes corresponding to the positioning holes, and the adjustment bolts are passed through the adjustment screw holes to the positioning holes for fixing.

2. The calibration fixture for an opacimeter filter according to claim 1, characterized in that: The material of the filter fixing back plate is aluminum alloy, and the surface of the filter fixing back plate is black oxidized.

Images