JPS594998B2 - Preservation management method for water-soluble metal working oil - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for managing the preservation of water-soluble metal working oil.

Water-soluble metal working oils such as cutting oils, rolling oils, and heat treatment oils meet the conditions for microorganisms to grow under aerobic conditions, so depending on the degree of control, they can grow significantly and lead to spoilage. There is.

In order to prevent spoilage of samples containing aerobic microorganisms such as water-soluble metal working oils at an early stage and to store them in favorable conditions, it is necessary to reduce the number of microorganisms in the sample, especially the number of viable aerobic microorganisms. It is necessary to always know.

Conventionally, as a method to measure the number of viable aerobic microorganisms such as yeast and bacteria in various samples, a predetermined amount of the sample is cultured on an agar medium, the number of colonies produced is determined, and the number of viable bacteria is calculated from the number of colonies. Although a calculation method has been used, this method not only requires complicated operations, but also has the disadvantage that it takes a long time to obtain a measurement result.

Instead of such agar culture method, a method has been proposed in which the catalase activity of aerobic microorganisms such as yeast and bacteria is measured to quickly calculate the number of viable aerobic microorganisms in a sample (Japanese Patent Publication No. 1973- 15999).

However, since the Warburg pressure method, Einhorn tube method, etc. are applied to measure catalase activity, it is necessary to use special equipment and containers, and their handling requires skilled techniques.

The purpose of the present invention is to eliminate these drawbacks and quickly determine the number of viable aerobic microorganisms in a sample using simple operations without requiring any special equipment, containers, or techniques at factories, warehouses, or other sites. The purpose of the present invention is to provide a method for measuring the decomposition of a sample, understanding the progress of decomposition, and performing appropriate preservative treatment.

In the present invention, a water-soluble metalworking oil and hydrogen peroxide are collected in a syringe, catalase activity is measured using a scale on the syringe, and the obtained measured values are plotted on a calibration curve to determine the preference of the metalworking oil. This is a method for preservative management of water-soluble metal working oil, which is characterized by determining the number of viable airborne microorganisms, grasping the progress of decomposition of the metal working oil, and performing appropriate preservative management.

The method of the present invention utilizes the catalase activity emitted by aerobic microorganisms to determine the number of viable bacteria, and has the feature that the activity can be measured with a very simple operation. There is.

That is, a sample is diluted as is or appropriately diluted, an appropriate amount is put into a syringe, and hydrogen peroxide is added to the syringe to generate oxygen gas.

In the present invention, catalase activity can be measured by reading the change in the amount of oxygen gas or liquid generated from the scale of the syringe.

Next, the number of viable aerobic microorganisms is calculated from the catalase activity thus obtained by preparing a calibration curve in advance and calculating from the calibration curve.

A suitable hydrogen peroxide solution for use in measuring catalase activity is one with a concentration of about 0.1 to 30%.

The reaction between the sample and hydrogen peroxide occurs at a temperature of 5 to 40°C.
0 minutes, preferably 5 to 30 minutes at 20 to 30°C.

Next, changes in the amount of oxygen gas generated or the amount of liquid put into the syringe are read from the scale on the syringe, and catalase activity is measured.

The change in the amount of oxygen generated or the amount of liquid thus obtained is converted into the number of viable aerobic microorganisms using a calibration curve.

The amount of oxygen generated is generally measured using the Einhorn tube method or the Warburg pressure method. However, with the Einhorn tube method, when a large sample is taken, the generated oxygen bubbles are dispersed in the liquid. Because it does not gather at the top,
Measurements must be made at low sample concentrations.

Therefore, measurement requires a long time.

In addition, in the case of the Warburg pressure detection method, the presence of air bubbles does not affect the measured value, but the entire device is large,
It also has the disadvantage of being expensive.

Furthermore, a problem common to both methods is that they require skilled techniques to obtain accurate measurement results, and are not suitable for on-site measurements such as factories and warehouses.

According to the present invention, since the sample and hydrogen peroxide solution can be directly collected with a syringe, not only is the expensive equipment described above unnecessary, but also a pipette for injecting the sample etc. into the measurement container. etc. are also unnecessary.

Moreover, even highly concentrated samples can be measured without the troubles experienced with the Einhorn tube method.

In addition, when measuring catalase activity, the reaction container and measurement container are the same, and the operation is very simple, so anyone can easily measure it on-site without requiring a large space or special technology. .

As described above, according to the present invention, the number of viable aerobic microorganisms in a sample of water-soluble metalworking oil can be measured simply and quickly, so that the quality of the sample can be appropriately controlled.

For example, in the case of metal working oil, which is one of the major types of lubricating oil, sterilizers are usually added to extend the usable life as cutting oil, rolling oil, heat treatment oil, etc., but a large amount of sterilizer is added from the beginning. It is uneconomical to use a disinfectant, and if used metal processing oil spills into wastewater, the disinfectant contained in the kernel oil may have an adverse effect on the human body or cause activated sludge in the wastewater treatment system. This will have a negative impact.

Considering this situation, it is desirable to add a bactericide when the number of viable bacteria in the metalworking oil increases, and to suppress the amount added as much as possible.

Therefore, by carrying out the present invention, which involves knowing the progress of decay in metal working oil using the above method and performing appropriate antiseptic treatment, it is possible to properly control the quality of samples, and it is also extremely effective in preventing secondary pollution. It is for use.

Next, the present invention will be explained in detail with reference to examples.

In addition, the calibration curve was created by the following method.

Creation of a calibration curve The number of viable aerobic bacteria in the sample metalworking oil was determined by the agar plate method, and the same sample was diluted to various concentrations and the amount of oxygen produced was determined by the method of the present invention.

A calibration curve for the number of viable bacteria and the amount of oxygen was created from both results.

Since there are differences between emulsion type metalworking oil and soluble type metalworking oil, it is necessary to create a calibration curve for each.

Note that the same calibration curve as for the soluble type can be used for the chemical solution type.

■) For emulsion type: In a 5R111 capacity syringe, collect various metal working oils 1- and 6% hydrogen peroxide aqueous solution 1- diluted with different concentrations of viable bacteria, and seal the injection port with a rubber stopper. The amount of oxygen gas was measured.

On the other hand, the number of viable aerobic bacteria in the sample solution of the same sample was calculated by the agar plate method.

That is, a certain amount of the sample solution was inoculated into a medium (pH 7.0) containing 0.5% meat extract, 1.0% peptone, 0.5% sodium chloride, and 1.5% agar, and cultured at 30°C for 24 hours. Then, the number of aerobic bacteria was calculated from the number of colonies generated.

Calibration curves are shown in FIGS. 1 and 2.

Figure 1 shows the results when a 30% hydrogen peroxide aqueous solution 1- and an emulsion type sample (metal working oil A) 1- were reacted at 21.8°C for a predetermined time, and Figure 2 shows the results when a 6% molten hydrogen peroxide solution 1- was reacted with the emulsion type sample (metal working oil A) 1- at 21.8°C. Hydrogen oxide aqueous solution 1- and emulsion type sample (metal working oil A) l
rnI! These are the results when reacting at 21.8°C for a predetermined time.

2) In the case of soluble type The test was conducted in the same manner as in the case of emulsion type using metal working oil B (soluble type) as a sample.

The obtained calibration curve is shown in FIG.

Example 1 Collect 1me of 6% hydrogen peroxide aqueous solution and 1rrll of metal working oil C (emulsion type) into a 5-liter syringe, seal the injection port with a rubber stopper, and rotate the syringe 2 to 3 times.
The reaction was carried out at ℃ for 10 minutes.

The amount of oxygen gas generated was 1.0 rnl, and the number of viable aerobic microorganisms determined from the calibration curve was 5.0×10 7 cells/year.

For comparison, the number of bacteria determined by the agar culture method was 4.6X.
It was 107 pieces/yd.

Examples 2 to 5 The number of viable aerobic microorganisms was determined in the same manner as in Example 1 except that the type of metalworking oil was changed.

The results are shown in Table 1.

For comparison, results obtained using the agar culture method are also shown.

[Brief explanation of the drawing]

Figures 1 to 3 are calibration curves for metal working oils.

Claims (1)

[Claims] 1. Collect water-soluble metalworking oil and hydrogen peroxide solution into a syringe, measure catalase activity using the scale on the syringe, and plot the obtained measured values on a calibration curve to determine the aerobic microbial growth in the metalworking oil. A method for preservative management of water-soluble metal working oil, which comprises determining the number of bacteria, understanding the progress of putrefaction of the metal working oil, and performing appropriate preservative treatment.