CN205382266U - Water drop sensors fabric - Google Patents

Abstract

The utility model provides a water drop sensor fabric, which can realize the detection of the presence or absence of water drops in large-area and irregular-shaped occasions. The fabric includes warp yarns and weft yarns. The warp yarns are made of non-conductive chemical fiber multifilament yarns and conductive yarns. Two kinds of conductive multifilament yarns, non-conductive chemical fiber multifilaments are used as the main yarn and two kinds of warp yarns are interwoven to form the main body of the fabric, conductive multifilaments are used as functional yarns, arranged at a certain distance along the warp direction, and alternately close to the left and right sides of the fabric The edges are separated by a certain distance. Preferably, when the conductive weft yarns are arranged at intervals along the warp direction, the distance between them is 2-10 mm, and the distance between them is 1-5 mm when they are close to one side of the cloth edge.

Description

water drop sensor fabric

technical field

The invention relates to a fabric and a production method thereof, in particular to a water drop sensor fabric and a production method thereof, belonging to the field of textile technology and sensor technology.

Background technique

At present, there are some small water drop sensors on the market, which can be applied to smart curtains, car wipers, and other occasions that need to detect the presence or absence of water droplets. This type of water drop sensor is generally formed by plating two grid-shaped electrodes on a tiny circuit board. It uses the conductivity of water to work, and its performance is stable, which can meet the requirements of general occasions. However, the disadvantages of this type of water drop sensor are also obvious: it can only realize the detection of small area and fixed position, which is not suitable for some important occasions. For example, a modern computer room is equipped with many important information equipment such as servers and workstations, which requires strict control of temperature and humidity. Most computer rooms are equipped with precision air conditioning systems. At this time, the object of waterproofing is condensed water whose position is not determined, and non-large-area detection cannot be realized. For another example, in the medical field, it is necessary to monitor the blood extravasation or sweating and urination of critically ill patients at any time. Not only does it need a large-area water drop sensor, but it also needs to be flexible.

For this reason, some new water drop sensors based on textiles have emerged at home and abroad. The patent "Precise Positioning Method for Sensing Cable Leakage Detection Based on Partial Pressure Compensation" (Application No. 201210285876.6) mentions a cable-shaped water drop sensor. Conductive thread to sense the presence of liquid water. Although such sensor cables are flexible, they have the disadvantage that they cannot be used over large areas. The patent "humidity sensor and its management system" (application number 200880012439.9) provides a humidity sensor, including two electrode plates and an absorbing layer for absorbing moisture in between, by real-time detection of the capacitance between the electrode plates One or two electrode plates can be fabric, but here the fabric mainly acts as two plates, and there is an absorbing layer in the middle, resulting in a certain thickness of the sensor, which is not conducive to its large-area use. The patent "knitwear with humidity sensor" (application number 201010610780.3) provides a kind of knitted fabric with humidity sensor, which adopts a grid-shaped electrode structure, and uses the change of the conductivity of the yarn when it meets water to detect the presence or absence of water droplets. The water drop sensor fabric adopts a knitted structure, which is suitable for underwear, but is not suitable for industrial occasions due to poor shape retention and firmness of the knitted fabric.

Therefore, research and manufacture a sensor fabric that is firm, reliable, fast in response, and easy to use can be used for the detection of condensation water and water leakage in machine rooms and warehouses, as well as the detection of blood extravasation, sweat and urine in infants and patients. The market prospect is broad.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the shortcomings of the above-mentioned background technology, and provide a water drop sensor fabric and a production method thereof.

The technical solution provided by the invention is: the warp yarn adopts non-conductive chemical fiber multifilament yarn and conductive yarn, the conductive yarn is arranged at the cloth edge position on the left and right sides, and the non-conductive chemical fiber multifilament is arranged on the cloth body; the weft yarn adopts non-conductive chemical fiber multifilament yarn. Silk and conductive multifilament yarns, non-conductive chemical fiber multifilaments are used as the main yarn and two kinds of warp yarns are interwoven to form the main body of the fabric, conductive multifilaments are used as functional yarns, arranged at a certain distance along the warp direction, and alternately close to the left and right A certain distance is cut off at the side selvedge.

For the water drop sensor fabric provided by the present invention, considering the size of the wetted surface formed when water drops on the cloth surface, and for saving materials, when the conductive weft yarns are arranged at intervals along the warp direction in the present invention, the distance between them is preferably 2-10 mm.

For the water drop sensor fabric provided by the present invention, in order not to damage the structure of the fabric and increase the difficulty of yarn cutting, in the present invention, the disconnection distance of the conductive weft yarn near one side of the cloth edge is preferably 1-5mm.

For the water drop sensor fabric provided by the present invention, the main function of the conductive weft yarn is to fully contact the warp yarn and conduct current, which is the contact of a bad conductor to a good conductor. Therefore, the conductive multifilament used in the conductive weft yarn in the present invention is a metal-plated chemical fiber multifilament or multi-strand metal wire.

For the water drop sensor fabric provided by the present invention, the main function of the conductive warp yarn is to contact the conductive weft yarn and conduct current, which is the contact of a good conductor to a good conductor. Therefore, in the present invention, the conductive thread used in the warp is preferably one of metal-plated chemical fiber multifilament, metal-plated chemical fiber monofilament, multi-strand metal wire, single-strand metal wire or its parallel twist with ordinary yarn Made of wrapped yarn.

When the water drop sensor fabric of the present invention is used, it is only necessary to clamp the cloth edges on both sides with common alligator clips and connect the low-voltage electricity. Under normal conditions, the selvedges on both sides are not conductive; when water droplets drip or adhere to the fabric body, the conductivity of the water will make the adjacent conductive weft yarns conduct, and the selvedges on both sides will also conduct with each other .

The benefits of adopting the present invention are: firstly, the present invention realizes the detection under the condition of large area, few water droplets and uncertain position; secondly, the present invention possesses the flexibility of the fabric and can adapt to various shapes and environments; thirdly, the present invention The invention responds quickly, is firm and reliable.

Description of drawings

The present invention will be further described below in conjunction with drawings and embodiments.

Fig. 1 is a schematic structural view of the water drop sensor fabric of the present invention.

Fig. 2 is a schematic structural view of the semi-finished product when the yarn is not cut during the production of the water drop sensor fabric of the present invention.

Fig. 3 and Fig. 4 are cross-sectional views of different positions of the semi-finished product when the yarn is not cut during the production of the water drop sensor fabric of the present invention.

Fig. 5 is an upper-machine diagram during the production of the water drop sensor fabric of the present invention, wherein "2" in "2×n" refers to the corresponding yarns in Figs. 1-4, "×n" means the number of cycles, and " 1×m” is similar.

detailed description

In Figure 1, the water drop sensor fabric is composed of non-conductive warp yarn 1, conductive warp yarn 2, non-conductive weft yarn 3 and conductive weft yarn 4, conductive warp yarn 2 is arranged on the left and right sides of the fabric, and non-conductive warp yarn 1 is arranged on the cloth body; non-conductive The weft yarn 3 is used as the main yarn and two kinds of warp yarns are interwoven to form the main body of the fabric. The conductive weft yarn 4 is used as a functional yarn, arranged at a certain distance along the warp direction, and alternately disconnected at a certain distance near the left and right selvedges to form a grid electrode.

Figure 1 shows the basic structure and principle of the water drop sensor fabric. However, there are many types of textile yarns. What kind of yarn should be used for non-conductive yarns and conductive yarns to make its performance reliable and respond quickly needs to be further optimized in combination with experiments.

First of all, it is necessary to select a suitable non-conductive yarn. At present, traditional yarns such as cotton, wool, silk and hemp and various commonly used chemical fibers are non-conductive yarns. In this case, the main factors for selecting yarns are the conductivity after water absorption and the speed of water absorption, and the secondary factor is cost. For this reason, when the present invention was carried out, the electrical conductivity of two kinds of yarns of chemical fiber multifilament and pure cotton single yarn were compared when meeting water. 75D/48F polyester network yarn is used, and the cotton yarn is C40S pure cotton yarn. The experimental results are shown in Table 1 and Table 2. Through comparison, it is found that although the resistance of polyester network yarn is greater than that of pure cotton yarn under normal conditions, the resistance of polyester network yarn after contact with water is smaller than that of pure cotton yarn, that is, the conductivity of polyester network yarn after contact with water is better than that of pure cotton yarn.

Table 1 Changes in the resistance of polyester network yarns to water (unit: MΩ)

Table 2 Changes in water resistance of pure cotton yarn (unit: MΩ)

In addition, considering that the sensor should have a faster response speed, the present invention also compares the speed of water absorption of different yarns and the fabrics formed by experiments. The test object is still the above-mentioned polyester network yarn and pure cotton yarn. The experiment method is to observe after dropping the colored ink with a dropper. The result proves that the water absorption speed of polyester network yarn is faster than that of pure cotton yarn. The experiment continued to compare the water absorption speed of the three fabrics in which the warp and weft are all polyester network yarns, the warp and weft are pure cotton yarns, the wefts are polyester network yarns, and the warp and weft are all pure cotton yarns. The results are: both warp and weft are polyester network yarns> The warp is pure cotton yarn and the weft is polyester network yarn > the warp and weft are pure cotton yarn. The experiment also found that the warp yarn is pure cotton yarn and the weft yarn is polyester network yarn. After absorbing water, the imprint is flat, and the other two are round. It also confirms that the water absorption speed of polyester network yarn is faster than that of pure cotton yarn. The reason is that although the hygroscopicity of cotton fiber is better than that of polyester, cotton yarn is twisted from cotton fiber, and the structure is tight, and it is difficult for liquid water to enter, while polyester network yarn is made of multiple polyester filaments combined together, and the structure is loose. When encountering liquid water, it is easy to form a wicking effect. Finally, in terms of cost, chemical fiber is much lower than pure cotton.

Based on the above factors, the non-conductive warp and weft yarns of the present invention are all made of chemical fiber multifilament, and the non-conductive warp yarn 1 and non-conductive weft yarn 3 of this embodiment are both selected from 75D/48F polyester network yarn.

After selecting the non-conductive yarn, it is necessary to select the conductive yarn. The selection of conductive yarn is more important. From the perspective of use, the greater the resistance of the water drop sensor fabric before encountering water, the better, and the smaller the resistance after encountering water, the better. At present, the conductive yarns commonly used in textile mainly include: metal filaments, multi-strand metal filaments, blended yarns such as metal staple fibers and cotton, chemical fiber monofilaments with metal plating, chemical fiber multifilaments with metal plating or any of them. Wrapped yarn twisted with commonly used yarns. The present invention selects 68D stainless steel filament, 32S stainless steel blended yarn (30% stainless steel fiber/70% polyester) and 70D/36F silver-plated filament respectively as conductive weft yarn 4, and considers weavability and selects silver-plated filament for use As the conductive warp yarn 2, the above-mentioned 75D/48F polyester network yarn was used as the non-conductive warp and weft yarn. After weaving into a 10cm×10cm sample, drip water and measure the resistance. The test results are shown in Table 3:

Table 3 Changes in water resistance of fabrics when different conductive yarns are used as weft yarns (unit: MΩ)

It can be seen from the test results that the conductive weft yarn 4 is not suitable for stainless steel filaments and stainless steel blended yarns. The reason why it is not suitable to use stainless steel blended yarn is that its own resistance is relatively large, reaching more than a thousand ohms per centimeter. In addition, the short stainless steel fiber is not continuous in the yarn, and it is not necessarily exposed at the contact with the warp yarn, which increases the contact with the warp yarn. Contact resistance of wet warp yarns. The reason why stainless filaments are not suitable for use is that they are relatively rigid and cannot be in good contact with warp yarns. In addition, they are single and have greater resistance. Therefore, in terms of material selection for the conductive weft yarn 4, conductive multifilament or multi-strand metal wire should be selected in order to obtain a larger contact resistance. In this embodiment, the conductive weft yarn 4 is a silver-plated filament of 70D/36F.

In terms of the material selection of the conductive warp yarn 2, since the main function of the conductive warp yarn is to contact the conductive weft yarn and conduct current, it is the contact of a good conductor to a good conductor, so the material selection can be metal-plated chemical fiber multifilament, metal-plated One of chemical fiber monofilament, multi-strand metal wire, single-strand metal wire, or the wrapping yarn formed by twisting with ordinary yarn. In this example, the use effect of 70D/36F silver-plated filament and its wrapping yarn formed with 150D polyester filament is compared at the same time. The results are shown in Table 4. It can be seen that it has little effect on the water conductivity of the fabric, which confirms the conductive warp yarn 2 selection method.

Table 4 Changes in water resistance of fabrics when different conductive yarns are used as warp yarns (unit: MΩ)

After the above experiments, the final water drop sensor fabric specifications in this embodiment are: fabric structure, plain weave; Roots, distributed on both sides as edge yarn; weft yarn, 75D/48F polyester network yarn, 70D/36F silver-plated filament; warp density, 283 threads/10cm; weft density, 220 threads/10cm. In the experiment, it was also found that water droplets falling on the surface of the fabric can generally form a wetting surface of about 2 cm, so it is better to control the spacing of adjacent conductive weft yarns below 1 cm. In this embodiment, the spacing between two adjacent conductive weft yarns 4 is 6 mm. That is, it is necessary to introduce a 70D/36F silver-plated filament every 13, and the calculation method is 13≈220/100*6. To form a grid-shaped electrode, each conductive weft yarn 4 should be disconnected by a certain distance at the conductive warp yarn close to the selvedge. In order not to damage the structure of the fabric and not increase the difficulty of cutting yarn, the disconnection distance is preferably 1-5mm In this embodiment, the conductive weft yarn 4 is cut off by 1 mm, that is, the distance between three warp yarns needs to be cut off, and the calculation method is 3≈283/100*1.

Because the water drop sensor fabric of this embodiment is a woven fabric, its structure is firm; because it adopts chemical fiber multifilament, it absorbs water quickly, responds quickly, and the cost is low; because it adopts silver-plated filament multifilament, the contact between conductive yarns is good , small resistance, stable performance.

The above-mentioned fabrics can be produced quickly on the current loom. The difficulty lies in cutting off the weft yarns of a specific length at the corresponding positions. In order to accurately and conveniently cut off the conductive weft yarns of the corresponding lengths at the corresponding positions to facilitate large-scale production, the following steps are adopted in this embodiment in production:

(1) Add the liner yarn. When warping or on the machine, add the lay-in yarns 5-1 and 5-2, as shown in Fig. 1 and Fig. 2, the position where the lay-in yarns are added is that the weft yarns on the left and right sides need to be disconnected. In this embodiment, both the laying yarns 5-1 and 5-2 are made of 140D nylon sewing thread to distinguish them from the warp yarns on the cloth surface.

(2) Drafting and reeding. As shown in Figure 5, the laying yarns on the left and right sides pass into a separate heald frame, but when reeding, they do not occupy a single reed tooth, but the warp yarns adjacent to this position pass into the same reed.

(3) Weaving. As shown in Fig. 3 or Fig. 4, when weaving in the non-conductive weft yarn 3, the warp and weft yarns are interwoven according to the plain weave, but the spacer yarns 5-1 and 5-2 are always located on the non-conductive weft yarn 3. As shown in Figure 3, when weaving the conductive weft yarn 4 at AA' in Figure 2, the part of the weft yarn that needs to be disconnected on the left side floats continuously on the three warp yarns to form a small section of weft float length. Below the part of the weft yarn, the weft yarn that does not need to be disconnected on the right side is still interwoven with the warp yarn according to the plain weave rule, and the side liner yarn 5-2 is still positioned on the weft yarn simultaneously. As shown in Figure 4, when weaving the conductive weft yarn 4 at BB' in Figure 2, the process is the same as above, but the left and right sides are interchanged. The surface structure of the fabric obtained by weaving is shown in Figure 2, and the upper machine diagram on which weaving is based is shown in Figure 5.

(4) Yarn cutting. After weaving finishes getting off the machine, lift it along the left and right liner yarns 5-1 and 5-2, and then cut off that part of conductive weft yarn pressed on it. After cutting, the laying yarns 5-1 and 5-2 fall naturally, and the surface structure of the obtained fabric is shown in Fig. 1 .

Through the above method, the yarn can be cut along the liner yarn when cutting the yarn, which is fast and efficient, and can be produced on a large scale.

The above embodiment is only a reference description of the present invention, and does not constitute any limitation to the content of the present invention. Obviously, different forms of structural changes can be made under the concept of the present invention, but these are all included in the protection of the present invention.

Claims (5)

1. A water drop sensor fabric, comprising warp yarns and weft yarns, characterized in that: the warp yarns are made of non-conductive chemical fiber multifilament yarns and conductive yarns, the conductive yarns are arranged at the left and right sides of the fabric, and the non-conductive chemical fiber multifilament yarns are arranged at the Fabric body; weft yarns are made of non-conductive chemical fiber multifilament and conductive multifilament yarn. Non-conductive chemical fiber multifilament is used as the main yarn and two kinds of warp yarns are interwoven to form the main body of the fabric. Arranged at a distance, and alternately cut off a certain distance near the left and right selvedges. 2. The water drop sensor fabric according to claim 1, characterized in that: when the conductive weft yarns are arranged at intervals along the warp direction, the distance between them is 2-10 mm. 3. The water drop sensor fabric according to claim 1, characterized in that: the distance between the conductive weft yarn and the edge of one side is 1-5mm. 4. The water drop sensor fabric according to claim 1, characterized in that: the conductive multifilament used in the weft yarn is metal-plated chemical fiber multifilament or multi-strand metal wire. 5. The water drop sensor fabric as claimed in claim 1, characterized in that: the conductive filaments used in the warp yarns are metal-plated chemical fiber multifilaments, metal-plated chemical fiber monofilaments, multi-strand metal wires, and single-strand metal wires. A wrapping yarn or a wrapping yarn twisted with ordinary yarn.