JP2018088869A - Check valve for soil sterilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a check valve for a soil sterilizer having an abrasion resistance and an improved leakage-prevention effect.SOLUTION: In a check valve for a soil sterilizer, a valve seat is configured by fitting an O-ring 3 in an annular O-ring groove 5a drilled inside a valve case 5. An inner circumferential end of the O-ring 3 projects from the annular O-ring groove 5a, in which a valve ball 2 abuts with the part of the O-ring 3 projecting from the O-ring groove 5a. In a stroke part of the O-ring groove 5a formed in the valve case 5 along which the valve ball 2 performs open-movement/close movement, an annular tapered part 5b is formed for guiding the valve ball 2.SELECTED DRAWING: Figure 3

Description

  The present invention is a check for preventing leakage of chemicals in a soil disinfecting machine that is mounted on the rear part of a tractor or rear part of a management machine, or is configured to be self-propelled and moves in the field and distributes the chemicals to the soil. It relates to the configuration of the valve.

The soil disinfectant kills bacteria and nematodes in the soil that may cause continuous cropping damage in some field crops by the power of the disinfectant that injects the cloth and does not cause damage even after continuous cropping. It is one of the effective working devices for spraying the disinfecting liquid that prevents it.
The chemical used as a soil disinfectant widely used as a means of soil disinfection is toxic chlorpicrin, which is designated as a deleterious substance, and is a highly toxic chemical. It is necessary to take preventive measures such as installing a manual cock to prevent chemicals from leaking from the discharge port in places other than the place where the liquid is discharged, or when moving the soil disinfectant mounted on the tractor in an unexpected place There is.

Furthermore, a liquid leakage prevention valve called a check valve is installed in a pipe that becomes a chemical flow path of the soil disinfecting machine.
In addition, since the chemical solution has strong corrosiveness, the parts constituting the check valve are designed using chemical resistant ones.

JP 2003-134983 A Japanese Unexamined Patent Publication No. 2011-155917

  The check valve of the soil disinfecting machine is configured to block the chemical liquid flow path when a ball serving as a valve is pressed against the valve seat portion by the force of a compression spring. In addition, the check valve of the soil disinfecting machine has a structure in which the chemical liquid pushed out of the pump pushes down the sphere when the chemical liquid is discharged, and the flow path is temporarily secured.

A ceramic material is used as the material of the valve ball constituting the check valve of the soil disinfecting machine. In addition, a stainless material is used as the material of the valve seat portion. This is chosen because both ceramic and stainless steel materials are highly chemical resistant.
However, when the ceramic ball repeatedly collides with the valve seat portion, there is a problem that the valve seat portion made of stainless steel is gradually worn out, and eventually the effect of preventing liquid leakage is lost.

  When the ceramic valve ball is pushed up by the compression spring and is not pushed up accurately to the center of the valve seat portion, the adhesiveness is not ensured, and there is a risk of liquid leakage.

  In general, there are various mechanisms other than the above in the structure of the check valve. The reason why the simple structure is selected for the soil disinfecting machine is to suppress the manufacturing cost and to make the chemical solution highly corrosive. This is because the materials that can be used for the check valve parts are limited. For example, if free-cutting steel is used, a check valve having a more complicated shape and a high liquid leakage prevention capability can be manufactured, but free-cutting steel cannot be used because of its low corrosion resistance.

  The present invention is configured as follows in order to eliminate the above-mentioned problems.

  In the first aspect of the present invention, a valve seat portion, a valve ball pressed against the valve seat portion, and a compression spring that presses the valve ball are disposed inside the valve case, and when the chemical liquid is not discharged, The ball is pressed against the valve seat by the urging force of the compression spring, so that the chemical liquid flow path is blocked, and when the chemical liquid is discharged, the chemical liquid pushed out from the pump pushes down the valve ball, In a check valve of a soil disinfector configured to temporarily secure a flow path between the valve ball and the valve ball, an O-ring is fitted in an annular O-ring groove formed in the valve case. Thus, the valve seat portion is configured, the inner circumferential end portion of the O-ring is protruded from the annular O-ring groove, and the valve ball is placed in a portion where the O-ring protrudes from the O-ring groove. It is configured to contact .

  The check valve of the soil disinfecting machine according to claim 1, wherein an annular taper portion that guides the valve ball to a stroke portion of the O-ring groove provided in the valve case in which the valve ball is opened and closed. Is configured.

  According to a third aspect of the present invention, in the check valve for the soil disinfector according to the first aspect, the valve ball is made of a ceramic material, and the O-ring is made of an inert fluororubber and made of an elastic resin. Use things.

  In claim 4, in the check valve of the soil disinfector according to claim 1, the valve case having an O-ring groove formed as an inner groove into which the O-ring is fitted from the inside is excellent in machinability. It is made of stainless steel material.

  According to the present invention, when the ceramic valve ball hits the valve seat, the ceramic ball is guided by the annular tapered portion and reliably moves toward the center of the valve seat. It is possible to suppress the probability of occurrence of liquid leakage due to the center deviation from the sphere, and to prevent the valve seat from being deformed by the center deviation.

  Adoption of rubber valve seat with elasticity improves adhesion to the ceramic ball significantly more than the adhesion between the valve seat part made of conventional stainless steel and the ceramic ball, improving the liquid leakage prevention effect In addition, it is possible to reduce work stress due to bad odor when liquid leakage occurs.

  The durability of check valve parts is greatly improved, and the check valve can be used for a long time, thus reducing running costs.

The top view of the state which attached the soil disinfector to the tractor. Rear view of soil disinfector. Sectional drawing of the check valve of a soil disinfection machine. The expanded sectional view of a check valve. A side view of a valve ball. The top view and side sectional drawing of an O-ring. The side view of a compression spring. Sectional drawing which shows the check valve of the conventional soil disinfection machine.

  As shown in FIG. 1, the soil disinfector 1 is attached to a tractor 100 that is a work vehicle. In this embodiment, although the soil disinfector 1 shall be attached to the tractor, it is not limited to this. Moreover, although the chemical solution supply part 30 is mounted in the front part of the tractor 100, and the chemical solution injection | pouring part 10 is mounted in the rear part of the tractor 100 so that it can move up and down by a work lifting / lowering apparatus, the chemical solution supply part 30 and chemical injection | pouring are carried out. The arrangement of the part 10 is not limited to this.

  The chemical solution supply unit 30 includes a chemical solution tank 31 and a diaphragm pump as the chemical solution delivery pump 41. The chemical solution delivery pump 41 includes a drive device 44 that is driven by a motor, and drives the chemical solution delivery pump 41 as a diaphragm pump. Further, on the outlet side of the chemical solution delivery pump 41, a confirmation meter 81 for visually confirming whether or not the chemical solution is being delivered is disposed.

  A chemical liquid injection claw 11 and a chemical liquid injection nozzle 12 are provided in the chemical liquid injection part 10 provided at the rear part of the tractor. The chemical solution delivered from the chemical solution delivery pump 41 and passed through the confirmation meter 81 is supplied to the chemical solution injection nozzle 12 through the tube 13. And the check valve C of the soil disinfection machine of this invention is interposed in the upper part of the said chemical | medical solution injection | pouring nail | claw 11, or the front | former stage of the chemical | medical solution injection | pouring nozzle 12. FIG. In FIG. 1, two check valves C are interposed in series. However, in order to more completely prevent liquid leakage, two or more check valves C may be interposed, and therefore the arrangement of the check valves C is not limited to this.

  In FIG. 8, the structure of the check valve of the conventional soil disinfector is illustrated. In the conventional check valve, the valve case 50 and the spring case 60 are screwed together by male and female screw parts and assembled together, the valve ball 20 is disposed freely in the vertical direction, and the compression spring 40 is viewed from below. Therefore, the pressure is urged toward the upper valve seat.

  In the conventional check valve, the configuration of the valve seat portion is such that a part of the valve case 50 is cut into an annular shape and the corner portion of the annular portion is used as the valve seat portion. Since the annular portion of the valve case 50 made of stainless steel constitutes the valve seat portion, the valve bulb 20 made of stainless steel repeatedly collides with the valve seat portion made of stainless steel. However, it is inferior in durability to the ceramic valve ball 20, and the situation such as damage, erosion and deterioration gradually occurs, and the sealing performance is reduced between the valve ball 20 and the valve seat portion 50a. There was a chemical leak.

  In the present invention, as shown in FIG. 3, by using a rubber O-ring 3 for the valve seat, it is possible to suppress rupture and wear due to the collision of the ceramic valve ball 2. In FIG. 4, the expanded sectional view of the part of the O-ring groove | channel 5a, the O-ring 3, and the annular taper part 5b is shown. In FIG. 5, a ceramic valve ball 2 is shown. FIG. 6 shows a plan view and a side sectional view of an O-ring 3 made of fluororesin rubber. FIG. 7 shows a side view of the compression spring 4 that pushes and urges the valve ball 2 from below.

  As shown in FIGS. 3 and 4, the check valve C of the present invention includes a compression spring 4 and a valve ball from the bottom inside a valve case 5 and a spring case 6 which are assembled by screwing with a male screw part and a female screw part. 2 and O-ring 3 are arranged. A tube insertion part 5 c to the tube 13 is provided at the upper part of the valve case 5, and a tube insertion part 6 c to the tube 13 is also formed at the lower part of the spring case 6. The compression spring 4 is fitted in a spring insertion hole 6 a provided in the spring case 6. The valve ball 2 pushed up from below by the compression spring 4 rises upward along the annular taper portion 5b, and the upper end portion of the annular taper portion 5b of the O-ring 3 fitted in the O-ring groove 5a. It is comprised so that it may contact | connect directly the part which protruded further inside from.

  Also, as shown in FIG. 4, the end of the inner ring portion at the upper portion of the annular taper portion 5b, so that the upper portion of the valve ball 2 is in contact with the O-ring 3 to constitute a liquid leakage prevention portion, A distance t is formed between the end of the inner ring portion of the O-ring 3 so that the O-ring 3 can protrude inside the annular tapered portion 5b. In this configuration, when the valve ball 2 closes the check valve C, the valve ball 2 is fitted in contact with the inside of the O-ring 3 to improve the sealing performance of both. The upper end of the valve ball 2 moves up and down along the annular taper portion 5b, but the valve ball 2 and the annular taper portion 5b are not in contact with each other in the closed state. The annular taper portion 5b serves to guide the raising and lowering of the valve ball 2 to the last.

  An annular taper portion 5b is provided in the upward movement stroke of the ceramic sphere so that the ceramic sphere is surely brought into contact with the center of the valve seat when the ceramic sphere is pushed up by the compression spring 4 toward the valve seat. The protruding position in the state of the annular tapered portion 5b is an annular portion located outside the inner diameter of the O-ring 3, and the inner diameter portion of the O-ring 3 is exposed at the upper end of the annular tapered portion 5b. It is configured. This exposed portion constitutes a valve seat portion with which the valve ball 2 contacts.

  Since the check valve C itself is a small part and the valve case 5 is also a small-diameter part, the O-ring groove 5a is cut into the inner diameter portion of the valve case 5 and the annular taper part 5b is precisely cut. It is difficult. Also, the finished surface after cutting is required to have high accuracy. Therefore, since it is difficult to process the inner groove with a conventional stainless steel material, a stainless material having chemical resistance and excellent machinability is used.

  The O-ring 3 used for the valve seat portion uses an O-ring excellent in chemical resistance. Further, since the O-ring 3 is made of a normal material and does not have durability as a valve seat portion, the O-ring 3 made of fluororubber is used. In this way, by using the O-ring 3 made of fluoro rubber for the valve seat portion, it is possible to further extend the use time by replacing the front and back of the O-ring, and it is possible to replace only the valve seat portion. .

  In addition, since the O-ring 3 must not be moved, the O-ring 3 needs to be fitted into the inner groove. However, since the part itself is small, the inner groove processing is conventionally performed for the valve seat part that also serves as the valve case 5. Since it is difficult, a stainless material having chemical resistance and excellent machinability is used.

  The most inert one among the fluororubbers can be said to be an elastic resin made of Teflon (registered trademark). High performance fluoropolymer, chemical resistance, solvent resistance, and oil resistance. In addition, the stainless material having excellent machinability is a free-cutting stainless steel with dramatically improved machinability.

C Check valve t Distance between the annular taper portion and the inner end of the O-ring 1 Soil disinfector 2 Valve ball 3 O-ring 4 Compression spring 5 Valve case 5a O-ring groove 6 Spring case 10 Chemical solution injection portion 13 Tube 30 Chemical solution supply portion 31 Chemical solution Tank 41 Chemical solution delivery pump 44 Chemical solution delivery pump drive device 81 Confirmation meter 100 Tractor

Claims (4)

A valve seat, a valve ball pressed against the valve seat, and a compression spring that presses the valve ball are arranged inside the valve case, and when the chemical solution is not discharged, the valve ball is attached to the compression spring. It is configured to shut off the chemical liquid flow path by being pressed against the valve seat by the force, and when discharging the chemical liquid, the chemical liquid pushed out from the pump pushes down the valve ball, and between the valve seat and the valve ball. In the check valve of the soil disinfector configured to temporarily secure the flow path in the
The valve seat portion is configured by fitting an O-ring into an annular O-ring groove formed in the valve case.
An inner circumferential end portion of the O-ring is projected from the annular O-ring groove, and the valve ball is brought into contact with a portion where the O-ring projects from the O-ring groove. Check valve for soil disinfector. In the check valve of the soil disinfector according to claim 1,
A check valve for a soil disinfector, wherein an annular taper portion for guiding the valve ball is formed in a stroke portion of the O-ring groove provided in the valve case in which the valve ball is opened and closed. In the check valve of the soil disinfector according to claim 1,
The valve ball is made of a ceramic material,
A check valve for a soil disinfecting machine, wherein the O-ring is made of an inactive fluororubber and made of an elastic resin. In the check valve of the soil disinfector according to claim 1,
A check valve for a soil disinfector, wherein the valve case having an O-ring groove configured as an inner groove into which the O-ring is fitted from the inside is made of a stainless material having excellent machinability.

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