JPS58200089A - Driving circuit of electromagnetic pump - Google Patents

Abstract

PURPOSE:To enable to obtain a rated discharge quantity of liquid from an electromagnetic pump at all times, by connecting a Zener diode to a constant circuit, and changing the duration for supplying current to the electromagnetic pump according to the change in the supply voltage of the electromagnetic pump. CONSTITUTION:A Zener diode 3 is connected to a time-constant circuit 2 which determines the width of pulses produced by a monostable multivibrator. When the supply voltage E of an electromagnetic pump 1 is changed from E1 to E2 (E1<E2), the width of pulses produced by the monostable multivibrator is reduced automatically, and the discharge quantity of the pump 1 is kept at a value substantially equal to the rated discharge quantity of the pump 1 at the time when the supply voltage is E1. Here, the discharge quantity of the pump 1 is selected in a desired manner by changing the frequency of trigger pulses applied to the base of a transistor Tr1 of the monostable multivibrator.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic pump drive circuit using a monostable multivibrator.

As a conventional circuit of this type, one using a basic single-chamber constant multivibrator as shown in Figure 1 is known.
The generated pulse radiation T of a monostable multivibrator is
is expressed as TK0.69OR...■ and is constant regardless of the power supply voltage 1 of the electromagnetic pump (&).

Here, 0 and R are a capacitor and a resistor that determine the time constant.

On the other hand, in a general electromagnetic pump, between the power supply voltage
... ■ A relationship is required.

Here, acid is a constant determined by the viscosity of the liquid discharged from the electromagnetic pump, and in the case of kerosene, the value is 1.05.
It is about 1.2.

From this, when the power supply voltage l of the electromagnetic pump (&) changes, in the conventional electromagnetic pump drive circuit using the basic monostable multivibrator, as shown from equation (2),
Since the generated pulse LLT of the multivibrator cannot be changed and, therefore, the energization width t of the electromagnetic pump (a) of type 2 cannot be changed, the discharge amount of the electromagnetic pump (a) cannot be changed before the power supply voltage l changes. Even if an attempt is made to maintain the set discharge amount, the inconvenience arises in that it is not possible to maintain the set discharge amount.

In order to solve the above problem, a monostable multivibrator that can be changed by the generated pulse intensity as the power supply voltage E changes is prepared, and if the power supply voltage 1 becomes higher than before, the monostable multivibrator Vibrator generated pulse @
By decreasing T, the energization width tt- of the electromagnetic pump is
It would be better if the discharge amount of the electromagnetic pump could be adjusted and maintained at the previously set discharge amount.

Based on this idea, a nest-stable multivibrator with two power supply IC-ICMs as shown in Figure 2 can be considered, but in this monostable multivibrator, It seems that if the actual voltage I changes, the generated pulse width that determines the energization width t will also change, adding up the formula ■. However, as a result of the experiment, (a) in Figure 5 was obtained.
As shown in , the discharge amount of the electromagnetic pump changes more or less due to a change in the power supply voltage E, so the equation (1) is not satisfied in Actual 116, and 1. However, this circuit had the disadvantage that it could not be used as a drive circuit for a t-m pump.

Therefore, as shown in FIG.
Generation of lJ monostable multivibrator/Zelsll1
Tr: We have devised a circuit in which a Zener diode (3) is connected to the time constant circuit (2) for determining the time constant.

According to this, the generated pulse width is Therefore, the formula ■ is satisfied.

Here, IC2 is the Zener voltage of Zener diode 7 (3).

Fig. 5 shows a modification of Fig. 4, in which (4) indicates a power supply, and the two 'WIL sources 1 + shown in Fig. 4 are
” M is a common power source, and (5)
is a Darlington connection of two transistors (61 (71), which corresponds to the normally non-conducting transistor Tr1 in FIG. 144.

An electromagnetic pump (1) intervened between the power supply (4) and the transistor (7).

The inventor of the present application conducted an experiment using the circuit shown in FIG. Since the discharge amount of does not change, it is recognized that formula (■) is satisfied, and in a precision device incorporating the electromagnetic pump (1),
If this circuit is used as the wA side path of the pump (1), the functions of the device can be fully demonstrated and the above-mentioned disadvantages can be solved.

Next, we will explain its operation (, the original electromagnetic pump (1)
) transistor Trl
When a trigger pulse is input to the base of , the transistor +t'r becomes conductive, and the time determined by the above equation (■), that is, Tr = -〇R1''m,
, -82, the electromagnetic pump (1) is energized. This operation is performed every time a trigger pulse is input, and the set lid liquid is obtained from the electromagnetic pump (II).

After that, the electromagnetic pump (power supply voltage of 11) is changed from m to R.
* (when L < m), the generated pulse width of the monostable multivibrator automatically decreases to X, −IZ Tl = −〇Rln−,
11it+lii IC2 The discharge lid of the electromagnetic pump (1) is maintained at approximately the same value as the set discharge - when the power supply voltage of the vL electromagnetic pump 1) is Di.

In addition, the transistor Tr of this monostable multivibrator
By changing the frequency of the trigger pulse input to the base of the electromagnetic pump +11, the discharge amount of the electromagnetic pump +11 can be freely selected.

As described above, according to the present invention, a Zener diode is interposed and connected to the time constant circuit that determines the pulse width generated by the 11 mf monostable multivibrator that drives the electromagnetic pump. The generated pulse width of the multivibrator and the energization width of the electromagnetic pump can be varied, and even if the power supply voltage changes, the electromagnetic pump has the effect of always obtaining a set discharge amount of liquid.

[Brief explanation of drawings]

Figure 1 is a failure circuit diagram of a conventional electromagnetic pump, Figure 2 is a circuit diagram of a monostable multi-valve regulator considered in the process of devising the drive circuit of the present invention, and Figure #I3 is the input voltage and flow rate of the electromagnetic pump. A characteristic diagram showing the relationship with the rate of change, K'WJ is a circuit diagram of a monostable multi-biplanar used in the drive circuit of the electromagnetic pump of the present invention, and FIG. 5 shows an example of another implementation of the circuit of the present invention. It is a circuit diagram. (1)...Electromagnetic pump (2)...Time constant circuit (3)...Zener diode patent applicant Sunpot Co., Ltd. Agent Kin Kitamura -'il! '、7・＝；1゛2 people Fig. 1 Fig. 2 Fig. 4

Claims (1)

[Claims] 1. A drive circuit for an electromagnetic pump in which an electromagnetic pump is driven by a monostable multivibrator, characterized in that a Zener diode is interposed and connected to a time constant circuit that determines the pulse width generated by the monostable multivibrator.