Academic Open Internet Journal

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Volume 11, 2004

RAISING THE COEFFICIENT OF TECHNOLOGICAL USE OF THE measure instruments BY INCREASE OF THE THEIR CONTROLLING INTERVAL IN METROLOGICAL LABORATORY

Tania Pehlivanova

TRAKIA UNIVERSITY STARA ZAGORA

BULGARIA

http://www.uni-sz.bg/

Abstract: In the article a methods for reorganization of the technical regulations for controlling intervals of the working measure instruments and diagnostics of aviation and radioelectronic appliances is proposed. The substance of the methods is comprised in raising of the controlling intervals for verification in the control-measuring labs, validity on the use of the apriori information for the technical condition of measure instruments, received in leading of the control verification in the exploit organizations during the time of the controlling limit.

The technological effectiveness of using the proposed methods is valuered and the operatively-economic effectiveness from its adopt in Bulgarian Airfors is analytical definit.

The measure instruments (MI) coefficient of technological use defines from:

(1) ,

where Т_О is mean time for work to MI refusal;

Т_R – mean time for MI reconstruction in control measuring laboratory (CML);

DТ_C – total time for MI metrologic control in CML.

The increase K_TU is possible when DT_C is maximum.

When realize this condition is nesesery to guarantee fixed probability for work without refusal P.

(2) _,

where Т_О = Т_О(t) dipend on time;

Т – time for uninterupted MI work.

Metrologic practice show, thet more then 80% from MI, entered for control in CML are in good repair. Estabilished regulation for metrologic control is connected with inadmissible loss of time and resources [5].

In this conection in the report is proposed a methods for reorganization of the technical regulations for controlling intervals of the working measure instruments and diagnostics of aviation and radioelectronic appliances. The substance of the methods is comprised in raising of the controlling intervals for verification in the control-measuring labs, validity on the use of the apriori information for the technical condition of measure instruments, received in leading of the control verification in the exploit organizations during the time of the controlling limit.

For comparison of offerd methods with existenced methods is expedient to use the graf-model:

Fig.1

1. MI in good repair.

2. Intermediate control verifikation into controling intervals.

3. Available metrologic MI refusal.

4. Absence metrologic MI refusal.

5. MI verifikation in CML.

6. Repair of damaged MI in CML.

7. Sudden MI refusal.

Generalised mathematical model of verifications and diagnostics process is used for comparison of efficiency two methods for metrologic control and diagnostics.

The summary time for metrologic verification and repair in CML is:

(3) , where n is number of oll verifications and Dt_Ci (i=1,2,…,n) is averadge time for one verification or repair.

The summary time for MI technical service Т_Е is divided into equal intervals Т_Cj, First cicle begins in moment t_о, corresponding to beginning of MI technical service.

Let the average number of demaged MI during every cicle is m. Probability for finding out of MI refusal is a£1. The find out demaged MI are changed with new MI or are repaired. If is the average number demaged MI in the begining of verification cicle k, number of repairing MI in the end of this cicle is . The average number demaged MI, which are not find out during the cicle k is .

The average number demaged MI in the beginning of k+1 cicle is , and number of demaged MI in the end of the k+1 cikle is

(4)

The decision of this equation were k=1 is , and were к ³ 1 is:

(5)

It follows from this equation, that when 0,5<a<1 when the number k increase changes insignificantli and . It give us right to say, thet the normative regulation MI verifications in CML (methods 1) with k cicles in Т_Е, may be changed with offerd methods for control and diagnostics MI, when during the time of service are carry out s control verifications, in exploit organization. Tereby controling interval Т_I increases Т^*_I=Т_I+D Т_I, and number of verifications in CML decreases (L<k) and it makes time and resources economy (methods 2).

The increased intervav Т^*_I defines from:

(6) ,

where Т_IS is control verifikation interval in exploit organization;

m_A - admissible value of refusal during the cicle Т_IS;

N – summary MI number.

To be equal average number of refusal for 1 cicle by methods 1 and methods 2 maximum number for s defines from:

(7) ,

When use methods 2 controling interval for verifications in CML is:

(8) Т^*_I = Т_I + DТ_I = s.Т_IS

increasing of controling interval is:

(9) DТ_I = Т_I - s.Т_IS > 0

This equation is truly if probabilitys for finding out of refusal in CML (a) and exploit organization (b) are equal (a @ b).

This may be realise if service personnel qalification is good and available appropriate technical resources in exploit organization.

Methods 2 may be used and when probability for finding out of refusal in service organization is b < a, but near to a. In this case in equatuation 7 a must be changed with b. In equatuations 9-11 s must be changed with s* < s.

When condition 9 is realized K_TU is:

(10) ,

were ,

Economic efficiency of methods 2 for increase MI controling interval is:

(11) ,

where

Introduction of methods for periodic metrologic MI verifications in Bulgarian Airfors have multiple effect.

In military standards criterion “value-efficiency” is [3]:

(12)

where K_ТU=K_R is readily coefficient, and

K_OR = K_ТU.Р - operative readily coefficient

(13) ,

where , ,

, .

(1+М₁).(1+М₂) @ 1 + М₁ + М₂, becouse М_1.М₂<<M_1,2

Introduction of offerd methods lead to relative operative economic multiple effect

(14)

The tentative value from this effect when ; h_с=0,7; K_ТU=0,95; =0,35 is from 7,6% to 22,8%. When controling interval increase more the effect increase in direct proportion.

Results and conclusions:

1.Methods for reorganization of MI metrologic control and verification is offerd.

2.Mathematical model for evaluation of tehnical and economic efficiency is developed.

3. The operative economic multiple effect from introduction in Bulgarian Airfos is determined.

References:

1.Aronovichus B.Sh. Metrologic, 1980, №3.

2. Bardou R, F. Proshan. Mathematical theory of reliability ,M., Sov.radio, 1969.

3.Belokireva S.D. Measure tehcnics, 1987.

4. Ekimov A.V., M.I. Reviakov. Reliability of electrical measure instruments., L., 1986

5.Kocev A.I., N Petrov. Technology for air tehcnics service by running tehnical condition. Methods for tehnical condition prognosis and air tehcnics resurs, introduct in Bulgarian Military Airfos, 1993

6.Novikov V. S. Tehcnical service radioelectronic equipment, M, Transport, 1987

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