On board test
Using the test plate set, included in this manual folder, you can easily test the functionality of the VISATRON® oil mist detectors and their connection to the safety system of the engine. The set can also be ordered separately under Part.-No. 11072. It consists of the following parts:
Test procedure step by step:
If applicable perform an additional pressure measurement to check the tightness of the suction system as described in chapter 7.3. Instead of an electronic gauge you can use the U-pipe manometer of the service box.
Factory test at engine builder with smoke generator on VN115/87plus and VN116/87plus installations
Both installation types can be verified by a smoke test. Due to vessels not normally having the equipment and SCHALLER AUTOMATION recommends this procedure only for the factory test by using the SCHALLER smoke generator (see Figure 57). If a smoke generator is available on a vessel this test can be also performed, however, in this case observe the following warning.
A complete test can be done only at standstill of the engine. The crankcase service covers must be opened first. Put a small amount of smoke fluid (see Chapter 'Accessories') into the reservoir and switch on the generator for a few seconds until the storage tank is completely filled with smoke. This is important so that the tank can provide sufficient smoke to complete the search run of a VN116/87plus installation to determine the correct engine side. The last step is to hold the flexible hose directly into the suction funnels until an oil mist alarm is indicated.
If it's not possible to open the service covers a functional test can be preformed without testing the suction funnels.
In this case the flexible hose has to be pressed over the opening under the lock screws of the siphon blocks as seen in Figure 58 or has to be pressed over the open header pipe end after removing the lock nut.
Additional pressure measurement on VN115/87plus and VN116/87plus installations
Perform the functional and smoke test as shown in the previous chapters 'On board test' and 'Factory test with smoke generator'.
Then carry out a pressure measurement at the end of the suction system. The engine including the oil pump must be at standstill.
On a VN115/87plus and VN116/87plus installation the tightness of the suction system can be determined by a pressure measurement at the outer siphon blocks or at the end of the header pipes.
This siphon block has an additional fitting for a manometer (see Figure 59). To remove the 17 mm lock nut you have to counter the 19 mm nut with a jaw wrench.
The pressure measurement procedure can also performed at the end of the 22 mm diameter suction pipes which are delivered from SCHALLER AUTOMATION. These pipes have also fittings for the manometer at the pipe end (see Figure 60).
Use only a digital manometer with a differential measuring method. On completion do not forget to lock all openings.
The minimal negative pressure values are defined in Table 4. They are only valid if a negative pressure of 60 mm WC is adjusted at the measuring head.
Factory test at engine builder with fog machine on all installations
This test includes the indication of an oil mist alarm as well as the indication of the affected compartment. Instead of the above mentioned smoke generator you have to use the more powerful fog machine (see Figure 61) with a fog bag with adapter (see Figure 62).
This equipment guarantees a constant fog concentration during the test and due to high density no influence of the additionally sucked in crankcase atmosphere.
Due to the increasing request of the ship owners and classification societies to test the OMD-system at running engines SCHALLER AUTOMATION recommends now following procedure.
The first test must be performed at standstill to secure, that the engine is well protected by the OMD system. If it is not possible to open the service covers or if it is not possible to access the suction funnels, e.g. on large 2-stroke engines, a functional test can be preformed alternatively using a special connection on the siphon block or respectively on the T-engine wall connection.
Fill the fog bag completely with fog and close the adapter with the yellow cap. The next step is to press the flexible hose of the fog bag adapter over the opened plug at the side of the siphon blocks as seen in Fehler! Verweisquelle konnte nicht gefunden werden. or over the open tube end at T-engine wall connections. Do not remove the hose until an oil mist alarm is indicated and the search run to indicate the affected compartment is finished. The plugs can be countered by an 11 mm jaw wrench to open or close the lock screw.
The second test can be performed on request at running engine using the plugs of the siphon block or the T-engine-wall connection to induce the fog.