KIMMON FLOW TOTALIZER
(*OBSOLETE* INFORMATION HERE FOR COMPARISON ONLY)

Even drips can be measured with high accuracy

1. Introduction

The central heating system lately popularized for home heating depend mostly on the method to supply hot water through a boiler using kerosene as a fuel.

In an apartment house, the fuel oil is pumped up from underground tank to roof tank and then fed to a service tank of each home by natural downstream force. The fuel oil in the service tank is to be fed afterward to the burner of a boiler with head difference of around 2 meters (6-feet). The capacity of the service tank is less than 30 liters and the flow rate is so small as 0.5 to 10 liter/h. In order to measure the fuel consumption of each home, accordingly, there is no other way to measure the practical feeding quantity of fuel by means of oil meter between the service tank and the hot-water boiler.

Flow meter NDR-6W (so called the drip meter) is developed for the purpose of measuring such small flow of fuel oil and is characterized by Japan's first oil measuring meter. This meter can be applied to a wide variety of fluids required very small amount measured such as water analysis for nuclear reactors, greenhouse heating systems, small size boilers and diesel engines, and etc.

2. Construction and principle of operation

The diaphragm chamber of this meter consist of two aluminum boxes facing in parallel and each of them is divided with a diaphragm into two sections. The respective sections are assembled at a phase difference of some 90° and connected with the inlet or the outlet by the valve which alternates the fuel route sliding on the valve seat. The new fluid, entering one section, is to press the diaphragm and send out the old fluid in the opposite section.

At the dead point, the section connected with the outlet will be replaced to the inlet and the diaphragm is to move in the contrary direction. This reciprocating diaphragm movement is is converted with a link to a rotational movement that turns the registration mechanism indicating the volume passed.

3. Features

• Head Loss is very low: Conventional piston type and single-valve type flow meters have suffered from high head loss (for instance, over 200 mmAq at a rate of 20 l/h in case of kerosene) which often caused the interruption of fuel feeding because of air collected in the piping could not be sufficiently exhausted. the head loss of this flow meter (NDR-6W), meanwhile, is so small as only 25 mmAq at the rate 20 l/h in the same case. This characteristic performance raises to a maximum the exhaust effect and reduces to a minimum the interruption of fuel feeding.
• Dust does not effect: In the piston type flow meters, dust tends to impede the motion of piston being collected in the gap scarcely left between the piston and the cylinder and besides at a piston ring in use, so that strainer is indispensable to check the entrance of dust. The NDR-6W and separate inner-mechanism, however, no strainer is generally required because the dust is to settle down outside the diaphragm sections so as not to affect the measuring mechanism.
• Water does not affect (in case of fuel measuring): In the piston type flow meters, the water may rust the piston or freeze in winter, but the NDR-6W separate inner-mechanism the water never affects the measuring mechanism even if it is frozen because it is collected outside the diaphragm sections and later it is discharged through the drain hole. If it should happen the meter filled with water by mistake, the meter must be dismantled from the line and turned upside down so the water will be drained from all parts of the meter.

4. Kinds of fluid to be measured

The DR-6 is actual production is designed for measuring kerosene but it is also available for light or heavy oil, machine oil, spindle oil and engine oil etc. Alcohol, ethylene glycol and others, in addition can also be applied by changing the material of some parts, so that any reference is willing to be received in company with data on the kind of fluid required, the oiliness and the working temperature, and etc.

5. Characteristics of registration accuracy

Owing the special design of this meter for extra small flow, the speed of revolving part is extremely slow paste, that is measuring mechanism makes 50 revolutions per hour at a rate of 20 l/h which is equivalent to only 0.8 revolution per minute. Accordingly, the force necessary to overcome the fluid resistance and diaphragm distortion resistance, namely, the difference between the pressures to be applied upon both sides of diaphragm is very small, and so the registration accuracy will hardly be affected even by the change of fluid resistance which depends on the kind of fluid. The oiliness of the fluid to be measured, however, will somewhat affect mechanical resistance. In case of the fluid of lower oiliness such as water, the registration will be a bit less than the practical value by certain increase of mechanical resistance. On the other hand, in case of the fluid of higher oiliness such as machine oil and the engine oil, the registration accuracy will hardly be affected in comparison with case of kerosene, though the mechanical resistance will slightly decrease.

Meanwhile, the mechanical resistance so small as under 20 mmAq enables oil layer to remain at all times between the valve and the valve seat, which prevents and leakage from the gap and consequently the registration accuracy maintained stable unlike the other flow meters so as not to be affected by change of gap flow which depends on the kind of oil.

6. Accuracy and minimum flow

• Accuracy: Plus of minus 1% of actual flow within specified range.

• Minimum flow: The minimum flow is 5 liters, that is accuracy of ±1% will be kept up when the flow more than 5 liters measured. It shall be taken into account that the accurate value will be lost in case of the flow less than 5 liters.

7. Fluctuation by temperature

the fluctuation of the instrumental error and head loss to be caused by the variation of temperature between +20°C and -20°C shall not exceed 1.0% and 10 mmAq respectively.

8. Loss of head

The loss of head for some fluid is listed below.

Fluid	Viscosity	Maximum flow rate (liters/h)	Head loss max. flow rate (mmAq)
Water	1	20	45
Gasoline	0.7	20	40
Kerosene	1.1	20	55
Heavy Oil	10	15	75
Engine Oil	321	10	130

9. Working flow range

The determination of working flow range for each kind of oil depends on the permissible head loss and flatness of instrumental performance curve. The date on kerosene indicates that the accuracy in working of ±1% is adaptive up to 50 l/h in view of the flatness of instrumental performance curve. Also for the fluid more viscosity, the metering accuracy of ±1% will be adaptive up to 50 l/h, if whole feeding system is not affected by increase of head loss. In case of minimum flow, meanwhile, no internal leakage will be caused and so it is possible to measure as low as 0.1 l/h.

10. Effect of electromagnetic valve

The oil feeding to a boiler will be controlled quickly by the opening or closing of electromagnetic valve, which effects on the instrumental error come out s follows:

• No difference of instrumental error is recognized between the non operational of electromagnetic valve and continuous operation of the same intervals of around two seconds.

• No difference of instrumental error is recognized between before the operation of electromagnetic valve and after its operation of 300,000 cycles.

11. Durability

The oil had been experimentally passed through the meter at the rate of 20 l/h every day over two years which total flow reached more than 20 kl. And every month during its term the registration accuracy had been checked at the rate of 0.5 l/h, 5 l/h, and 20 l/h respectively and its results demonstrated the accuracy within ±1% in all cases.

12. Connection

Connection: 8mm (15A gas pipe or 8mm copper pipe), Adaptors accept 1/8" male NPT fitting

Standard specifications

• Flow Range: 0.1L/h - 20L/h
• Maximum working pressure: 0.1MPa (1.0kgf/cm²) (1 atm)
• Maximum working temperature: 45°C
• Accuracy: Within ±±1.5% (4L/h to 20L/h)
• Maximum registration: 99999.99 liter
• Minimum Registration: 0.00% L
• Minimum scale: 0.02 liter
• Weight: 1.3 kg
• Inlet: Left
• Inside diameter: 8 mm
• Connection: 8mm (15A gas pipe or 8mm copper pipe), Adaptors accept 1/8" male NPT fitting

Measuring flow range

Fluid	Viscosity	Flow range (liters/h)
Water	1	0.1 ~ 20
Gasoline	0.7	0.1 ~ 20
Kerosene	1.1	0.1 ~ 20
Heavy Oil	10	0.1 ~ 15
Engine Oil	321	0.1 ~ 10