CC BY
5A gricultural
Bulletin of Stavropol Regi
Stavropol Region
= № 1(21)/1 Supplement, 2016
UDC 631.331
Anatoly T. Lebedev, Nikolai V. Valuev, Nikolai A. Mar'in, Roman V. Pavlyuk, Aleksander N. Mar'in
TECHNO-ECONOMIC MODEL OF COMPARATIVE ASSESSMENT OF EFFICIENCY OF RESOURCE INCREASE OF FRICTION PAIR «DISK - GASKET» OF PNEUMATIC SEEDING MACHINE
Pneumatic vacuum seeder-cultivators «Millerovosel-mash», «John Deere», «MashioGaspardo», «MaterMa-cc», «Monosem», «Kunh» and others, both domestic and imported, with disk sowing attachment are most widely used for planting row crops. Planting attachments of lower position provide precise sowing of sunflower, corn, sugar beet and other row crops. However due to rapid wear of replaceable parts of a metering disk and a gasket there is a disturbance of seeding and observed thinned and thickened shoots, which leads not only to a decrease in crop yield but also to overspending of seeds. Precautionary replacement of metering disks and gaskets leads to underuti-lization of pledged resources and increase in material costs of operation especially for imported planters. Therefore, to increase the efficiency of the friction pair «disk - gasket» it is necessary to ensure the wear resistance of working
surfaces of friction pairs «disk - gasket» which should be 1.5-2 times greater than a serial friction pair has. From this perspective, we have proposed a number of technical solutions that meet stated objectives, suggested ways to conduct a comparative assessment of economic costs depending on the operating time as compared to serial metering disks and gaskets. The use of reinstallation of a disk to another working position and saturation of a gasket with an anti-friction material improves resource of friction pair «disk - gasket», reduces the multiplicity of operations related to repair, and eliminates the costs associated with the loss of production.
Key words: seed disk, gasket, wear, anti-friction material, durability, seeding set, wear of pair of friction.
Anatoly Timofeevich Lebedev -
Doctor of Technical Sciences, Professor, Head of the
Technical Service, Standardization and Metrology Department,
Dean of Farm Mechanization Faculty
Stavropol State Agrarian University,
Stavropol
Tel.: 89614986423
Nikolai Vasilevich Valuev -
Doctor of Technical Sciences, Professor Technical Services in Agriculture Department Azov-Black Sea Engineering Institute Don State Agrarian University Zernograd
Nikolai Alexandrovich Mar'in -
Ph.D. in Technical sciences, senior lecturer,
Technical Service, Standardization and Metrology Department
Stavropol State Agrarian University
Stavropol
Tel.: 8 (8652) 35-65-52 E-mail: t707oa@rambler.ru
Roman Vladimirovich Pavlyuk -
Ph.D. in Technical Sciences, associate professor,
Technical Service, Standardization and Metrology Department
Stavropol State Agrarian University,
Stavropol
Tel.: 89187579456
E-mail: roman_pavlyuk_v@mail.ru
Alexander Nikolaevich Mar'in -Ph.D. in Agriculture, associate professor Department of Soil Science named after V.I. Tyulpanov Stavropol State Agrarian University, Stavropol
Tel.: 8 (8652) 35-65-52 E-mail: t707oa@rambler.ru
Pneumatic vacuum seeder-cultivators «Mil-lerovoselmash», «John Deere», «Mashi-oGaspardo», «MaterMacc», «Monosem», «Kunh» and others, both domestic and imported, with disk sowing attachment are most widely used for planting row crops. Exchangeable metering disks provide accurate sowing of sunflower, corn, sugar beet and other row crops [1].
Planting attachments of lower position due to lack of seed hoses improve the uniformity of distribution of seeds in a row but operate in the area of dusty air with increasing concentration of powdered abrasive which gets into the friction zone of metering disks and gaskets. Since planting crops is carried out in short agrotechnical terms, almost 100% reliability of seeding-machines and their components is required, hence it is allowed to use units with worn parts in-
cluding metering disks. It results in disturbance of the process of planting and emergence of thinned and thickened shoots, which leads not only to a decrease in crop yield, but also to overspending of seeds. Precautionary replacement of metering disks and gaskets leads to underutilization of pledged resources and increase in material costs of operation especially for imported planters.
Metering disks and gaskets for planting row crops produced by modern companies operate with various outputs before replacing and have different selling cost. Criteria for culling metering disks and gaskets are not determined in operating instructions for seeders. At the same time there are only approximate data on the frequency of replacing them received for specific designs of seeding machines operating in certain production and climatic conditions and with different annual load of
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seeders. Some dealer firms and manufacturers justify the high selling cost by large enough projected resources. On the other hand, manufacturers of cheaper metering disks and gaskets for planting row crops assure undoubted effectiveness and likeness to original spare parts, even though they have a lower production before replacing them. Selecting metering disks and gaskets only by their resources does not allow to reliably determine the effectiveness of these metering disks and gaskets. Therefore, different approaches are used for comparative evaluation of effectiveness of different types of metering disks and gaskets [2].
Prerequisite of reliable assessment of a metering disk and a gasket of different manufacturers is reliability of implemented technological process of planting crops with the index of at least 0.97 in all compared cases. The compliance with agro-technical requirements for the actual depth of planting and seeding rates may be used as the main criterion for the reliability index of the process of planting row crops.
Other condition for an objective analysis of compared options of metering disks and sealing materials is that the crop is produced on the same soil types, with the same units, by the same qualified mechanic.
Researchers agree that the wear of the units is proportional to the duration of their service life, with the exception of a brief warm-up period and the period of accelerated wear at the end of service life. The latter period, according to many researchers, is not observed at all for a number of parts. In this connection, the line characterizing the wear is often considered as a straight line for simplicity of construction.
An important scientific and technical challenge to increase the efficiency of use of agricultural technology is the development of activities and ways to increase resources and reduce time spent on the restoration of operability of units and parts. This problem is most acute during planting row crops which takes place in short agrotechnical terms and is associated with biological characteristics of seed germination of plants [3].
To develop ways of increasing the resources of the friction pair «disk - gasket», the life cycle of existing serial metering disks and gaskets will be considered. Changing the thickness of a metering disk and a gasket before reaching their limit values are graphically represented as curve 1 (Fig. 1).
In the initial period of time T® operation occurs at a constant rate of wear U^ during this time. Then, when the wear hB (point A) is reached, the process of wear is intensified due to increased vibration and continues as long as the thickness of the metering disk and the gask hnp et does not reach the maximum permissible value . Period T™ characterizes the work of sowing attachment which does not comply with agro requirements [4].
Service life of a serial seeding set can be determined by the formula
TCP = T+T™. (1)
Figure 1 - Scheme for serial and proposed lifetime of the friction pair «disk - gasket»
Achieving this specified limit may be regarded as a failure of the friction pair «disk - gasket» because in this period overrun significantly increases and missing of seeds is observed, and further operation is inappropriate for economic reasons [5]. Thus, the time period T® can be regarded as the main stage of the life cycle of the friction pair «disk - gasket» upon completion of which it is necessary to replace them. Total value of wear of the friction pair hB of a seeding set should be determined to control and scientifically validate reasonability of this period of operation TnP.
Service life of the proposed seeding set with an increased resource can be calculated by the formula
Tm> Kyp
(Tcp-T;
nn\ p /
(2)
KyP - magnification factor of the resource.
Comparative assessment of metering disk and sealing materials is carried out using technical-economic indicator 3n which is the ratio of total costs 30E^ and performance of a given amount of work T and is calculated by the formula _ 3r
OEIIJ
T
(3)
Total costs for implementation of a given amount of work (Fig. 2) can be represented by a multiplicity of replacement of serial sets K and purchase costs, delivery and wages for replacing a metering disk 3^ and a gasket 3yn, spent funds related to the loss of production as a result of overseeding and under-seeding of seeds 3nn in the form
* (4)
3C
OEIH
K(3
+ 3 +3
AZJ T Jyjj T -»nn
>
The need to replace metering disks and gaskets was determined by the formula
T
K = —, (5)
TCP
TCP - average values of the resource of a seeding set, ha.
Placing formula (5) into (4) we obtain T
(6)
3C
OEII[
T
CP
As noted above, the resource of a seeding set is determined by intensity of wear of working surfaces of the related parts.
Agricultural
Biilli-tin of Stavropol Region
№ 1(21)/1 Supplement, 2016
The ideal option to increase the effectiveness of work of the proposed friction pair can be considered an increase in one normal operating period to operating period corresponding to the seasonal volume of work or more, but multiple to it in order to avoid downtime during planting. This development of
the state of the working surfaces of the friction pair «disk - gasket» is described with the curve 2 in Figure 1. However, due to different seasonal load under real production conditions this value cannot be accepted as an objective characteristic for replacement of a set [6].
Figure 2 - Techno-economic model of implementing a given volume of seeding row crops and total costs
for a serial seeding set
Analysis of the given above leads to the conclusion that in order to increase the efficiency of this set it is necessary to look for alternative ways to solve this problem. One should take into account the seasonal workload of a seeding attachment as well as the fact that the proposed technical solutions should be implemented both at the production stage and at the stage of repairs since the farms at the moment already have quite a number of domestic and imported row planters.
Consequently, to implement the proposed approach to improve the effectiveness of work of the proposed friction pair «disk - gasket» it is necessary to ensure the wear resistance of working surfaces of friction pairs «disk - gasket» which is 1.5-2 times greater than a serial friction pair has [7].
From this point of view, we have proposed a number of technical solutions that meet their stated objectives (Fig. 3).
Повышение ресурса
Перестановка диска в другую рабочую позицию
Перестановка ворошильных флажков в другую рабочую
позицию
Замена уплотнительной прокладки
Насыщение антифрикционным материалом
Насыщение уплотнительной
прокладки антифрикционным материалом
Насыщение уплотнительной
прокладки антифрикционным материалом
Перестановка ворошильных флажков в другую рабочую позицию
Замена уплотнительной прокладки на насыщенную антифрикционным материалом
Новый способ №2485749
Figure 3 - Areas of resource increasing of the friction pair «Disk - gasket» of sets row of sowing drills
To maintain a healthy state by the first method a serial dispensing disk and the gasket operatetillwear hB, followed by reinstalling the agitator flags to the
new working position of the disc with replacement of gasket [8-10].
Costs associated with the work to increase the share of the first proposed method (Fig. 4) can be identified as:
3 " =3OT +23^ +3„.. (7)
where 3nE - the cost of reinstallation of agitator flags to another working position, rub.
Expressing all of the costs for the use of the first method as a fraction of the cost of acquisition, delivery and wages by replacing the dosing disk and gasket 31, we obtain:
3f =3w.(l + 2Kyn+Kim), (8)
where - the cost of purchasing, installing and salaries when replacing the dosing disk, rub.; Kyn - coefficient taking into account the increase in value of 0.2 ... 0.25 of the cost of the purchase and replacement of seed set when purchasing a gasket; KnE - coefficient taking into account the increase in value of 0.05 ... 0.1 of costs for the purchase and replacement of metering disk when performing permutation flags agitator drive to another working position.
Costs for the purchase, installation and salaries by replacement of seed set we obtained by a formula:
^bk _ ^ftzi; + 3yn. (9)
After conversion, we get the expression
^oei _ ^BK -K0E1, (10)
where K^ - generalized coefficient taking into account the increase in the cost of the application of complex operations to improve resource.
Knowing the coefficients increasing the cost of ongoing method of increasing longevity, you can get the value of the generalized coefficient within KCB1 = 1.45 ... 1.6.
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Figure 4 - Technical and economic model of the overall costs of implementation of predetermined volume seeding row crops when reinstalling the agitator flags on the metering disk (method 1)
Please note that you need to perform operations on the life extension of the metering disk and gasket, and replace them when they reach defect wear in order to avoid the additional costs associated with the loss of seed as a result of reseeding and insufficient sowing [11].
One of the promising areas to increase the durability of the friction pair «disk -gasket» is the saturation of the protrusions gasket antifriction lubricant in the area of contact [12].
The solid lubricant produces the thinnest protective film penetrating into existing micro pores on the surface of sliding parts, reduces plastic deformation of the material, promotes redistribution of pressure and thus provides a favourable running surfaces, thus increasing the product life, to reduce the loss of working time because of the fault and higher productivity (fig. 5).
The most famous of the short list of solid lubricant is graphite - black mineral with a greasy luster, oily to the touch. The antifriction material is graphite, due to such advantages as low coefficient of friction, good adhesion to lubricated surfaces, a small force of destruction when it is used in the solid state, low cost, availability, etc. It is found in nature, and is also produced in electric furnaces. The synthesized product is at least 99% consists of pure carbon. The main advantage of the graphite is perhaps that it forms a strong film on the friction surfaces (Figs. 6-7).
Figure 5 - Antifriction lubricants and coating for units of dry friction
/% gricultural
Bulletin of Stavropol Beg
№ 1(21)/1 Supplement, 2016
Figure 6 - The scheme of operation without lubrication
Figure 7 - The scheme of operation with a solid lubricant
Subsequent contact of the pair of friction occurs contact with the gasket, reaches the wear limit hB. How-with graphite surfaces, and as a result, the friction co- ever, this requires you to reinstall agitator flags on un-efficient f is reduced to 0.02 ... 0.05, and therefore in- worn surface of the disk, which is economically more
creases the durability of the connection. We got the patent for the invention № 2485749 [13].
The next step of maintaining an operable state is
advantageous than buying and installing new metering disc. After reinstalling the disk into another operating position it mates with a new gasket, saturated with
a permutation of the sowing disk to another working solid lubrication points, thus extending its life by more position. This step is realized after the disk surface in than 2 times (Fig. 8).
Figure 8 - Technical and economic model of the overall costs of implementation of predetermined volume
of row crops seeding using 2-nd method
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The cost to increase the duration of the seed set, made in the off-seasonin thesub-step 1 can be identified as:
2 = ^^flfl^^yn^^H/ (11)
where: - thecostofpurchasing, deliveryandsalarie swhenreplacingthedosingdisc, rub.; 3yn - the cost of purchasing, delivery and salaries when replacing the gasket, rub.; 3H - thecost of saturation gasket with antifriction material, rub. The costs related to the rearrangement of agitator flags and followed by saturation of the sealing material in the sub-step 2 can be determined by the expression: 3? = (3^+3^3^) (12)
where 3nE - the cost of a rearrangement of agitator flags in another working position and hardening, rub. Then the overall costs associated with increased seed mass resource set according to the second method, can be defined by the expression:
32 = 3^ + 23yn + 23H + 3^ (13) Expressingallthecomponentsofthetotalcostofus-ingthesecondmethod, asafractionofthecostofacqui-sition, deliveryandsalariesbyreplacingthedosingdis-kandgasket 3" weobtain
32 = 3m ■ (i ■+2Kra +2KH+Km), (14) where KH - coefficient taking into account the increase in value at 0,025 ... 0,075 from the cost of purchasing and replacing the dosing diskwhen the saturation of the antifriction sealing material composition.
We get the expression
3oE2 = 3BK ■ ^OB2, (1 5)
where KOE2=1,5...1,75.
Accordingtopreliminarydata, theuseofthepro-posedcomplexworkperformedtoimprovethedurabilit-yoftheseedsethastheadvantageofwinningthecostso-flossofproductionandreplacedserialmultiplicityofme-teringdisksandgasketstoculling.
A3 = K3BK + I0 3nn -KOB ^3^ (16)
Substituting the values of expression and simplifying, we obtain
A3 = 3bk(K-Kob)+K3iiii. (17)
Thustheuseofmethodsreinstallationdisktoan-otherworkingpositionandsaturationgasketanti-fric-tionmaterialimprovesresourcefrictionpair «disk-gask et»toreducethemultiplicityofoperationsrelatedtother epairandeliminatethecostsassociatedwiththelossof-production.
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1. Marin N. A. Improving resource metering drives pneumatic drills row: author. dis. ... cand. tehn. science. Michurinsk: Science City of the Russian Federation, 2015. 19 p.
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3. Lebedev A. T., Marin N. A., Kaa A. V. The study
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4. Impact of wear of sowing kit pneumatic drills on the quality of planting row crops /A. T. Lebedev, N. V. Valuev, N. A. Marin, A. V. Zaharin // Agricultural Bulletin of Stavropol Region. 10. 2014. № 2 (14). P. 65-70.
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6. Influence of soil composition on the performance and wear of friction pairs sowing apparatus / A. T. Lebedev, N. A. Marin, A. N.12. Marin, P. A. Lebedev, R. V. Pavlyuk, E. N. Korolev // Collection of scientific works SWorld. 2013. V. 11, № 3. P. 91-95.
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in the production of agricultural products. New technologies and equipment for a new
generation of crops and livestock. Tambov: All-Russian Research Institute for the use of machinery and petroleum products Agricultural Sciences, 2013. P. 32-36. Analysis of the possibility of organizing a disaster recovery disc sowing machines pneumatic drills / A. T. Lebedev, N. A. Marin, A. N. Marin, E. N. Korolev // Collection of scientific works SWorld. 2012. V. 6, № 2. P. 97-100. Pat. 2485749 Russian Federation MPK51 A01S 7/04. Gasket for pneumatic sowing machine / A. T. Lebedev, N. A. Marin, A. V. Kaa [etc.]; applicant and patentee VPO «Stavropol State Agrarian University.» - № 2012101155/13; appl. 11.01.2012; publ. 06.27.13. Bull. № 18. 9 p. Increase of wear resistance of the friction pair pad disk sowing apparatus / N. A. Marin, A. N. Marin, A. T. Lebedev, E. N. Korolev, A. S. Shumsky // Rural mechanic. 2013. № 7 (53). P. 35. Lebedev A. T., Marin N. A., Marin A. N. Increased durability of the friction pair «disk-pad» sowing apparatuses row seeders // Science in Central Russia. 2014. № 3 (9). P. 41-47.
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