JPH0475115A - Constant temperature fluid supply device - Google Patents

Abstract

PURPOSE:To obtain fluid whose exit temperature near to desired constant temperature can be kept by interposing an adjusting passage between a temperature sensor to measure the entry temperature of a pipeline and a heater. CONSTITUTION:The adjusting passage 11 of volume V is interposed between the temperature sensor 15a which measures the entry temperature T1 of the pipeline and the heater 16, and relation between the global proper delay time th of the first temperature sensor 15a and the heater 16 and a flow rate Q in the pipeline is set as V=QXth. Therefore, the fluid with micro mass flow rate DELTAm measuring the temperature T1 by the first sensor 15a can arrive at the position of the heater 16 after the lapse of time th even when the proper delay time th as inevitable physical properties exists, and required heating in accordance with the temperature T1 is received from the heater 16, and the fluid at the desired constant temperature Ts can be discharged. Thereby, it is possible to reduce deviation between the exit temperature To and the constant temperature Ts as possible.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a constant temperature fluid supply device that supplies gas or liquid at a constant temperature, and is used, for example, when supplying lubricating oil to the main shaft of a machine tool. .

[Conventional technology]

FIG. 3 is a pipe diagram of a conventional example, in which lubricating oil heated by a machine tool flows into a cooling chamber 2 from a suction port 1. The lubricating oil in the cooling chamber 2 is cooled by an evaporator 3 of a refrigerator (not shown). The cooling chamber 2 is connected via an inlet 4 to a micro-temperature heating chamber 7 equipped with a temperature sensor 5 such as a thermistor and a heater 6. In order to bring the temperature To of the lubricating oil supplied from the outlet 8 to a desired constant temperature T5, the lubricating oil is heated in the cooling chamber 2,
- Once the temperature is cooled to a temperature TI slightly lower than Ts, the temperature is measured by the temperature sensor 5, and then a small amount of thermal energy is applied by the heater 6 to adjust the temperature to Ts. A sheathed heater or the like is used as the heater 6, and the operation is performed by controlling the ON-OFF operation of the refrigerator or by controlling the ON-OFF time of the power source of the heater 6 using an electromagnetic contactor.

[Problem to be solved by the invention]

In the conventional technology described above, since the refrigerator is operated in ON-OFF mode, the temperature TI of the lubricating oil at the inlet 4 fluctuates. Even if the refrigerator is operated by an inverter, the difference between the temperature Ts and the desired temperature Ts cannot be avoided.

Further, in the micro-temperature heating chamber 7, the thermal energy output by the heater 6 is also under ON-OFF control, and deviations in temperature control cannot be avoided. In particular, there is a detection delay time of the temperature sensor 5 such as a thermistor, and a comprehensive inherent delay time such as the heater 6 obtaining electric power and transmitting thermal energy to the lubricating oil.
Since the temperature sensor 5 and the heater 6 coexist in the micro-temperature heating chamber 7, the temperature To of the lubricating oil supplied from the outlet 8 inevitably deviates from the desired constant temperature Ts. Even if the temperature sensor 5 is placed downstream of the heater 6 and provides feedback, T
Since s changes over a small range, fluctuations are inevitable even if To is made to match Ts on average.

An object of the present invention is to provide a constant temperature fluid supply device that can minimize the deviation between the outlet temperature To and a desired constant temperature Ts when applying a small amount of thermal energy to a fluid having a fluctuating inlet temperature T1.

[Means to solve the problem]

The constant temperature fluid supply device of this invention 1 includes a first temperature sensor that measures the inlet temperature T1 of the pipe, a heater downstream thereof, and a power W that increases the fluid to a desired constant temperature Ts. In a constant temperature fluid supply device comprising a power calculation output circuit that outputs output to a heater, an adjustment flow path having a volume V is interposed between the first temperature sensor and the heater, and the first temperature sensor and the The overall inherent delay time th of the heater and the flow rate Q flowing through the pipe
Regarding, V=QXth.

The constant temperature fluid supply device of invention 2 is characterized in that in invention 1, a second temperature sensor that measures the downstream outlet temperature To of the heater, a delay circuit connected before or after the power calculation output circuit, and a setting-specific The apparatus includes an error time calculation circuit that calculates a set error time thd between the delay time ths and the true value, and adjusts the delay time tb of the delay circuit so that the set error time thd becomes zero.

The constant temperature fluid supply device of Invention 3, in Invention 1 or 2, A fluid mixing chamber is connected to the outlet of the pipeline.

The constant temperature fluid supply device of invention 4 is based on invention 1.2 or 3, wherein a feed hack circuit is interposed between the second temperature sensor that measures the downstream outlet temperature To of the heater and the power calculation output circuit. This is to adjust To to the above-mentioned Ts.

[Effect]

This will be explained with reference to FIG.

In invention 1, the conditions under which the power calculation output circuit 21 outputs the power W will be explained first.

When a fluid with an inlet temperature Ts flows in at a flow rate Q, if the specific gravity is γ, the minute mass Δm at a minute time Δt is calculated by the following equation (1
) is given by

Δ゛m=γQ・Δt...(1)6
m fluid from temperature T1 to desired constant temperature T in time Δt
The thermal energy required to raise the power to s is the power W
If the specific heat of the fluid is C, then c ('rs -TI) Δm+=W・Δ
t-- (2), and by substituting equation (1) into equation (2) and dividing both sides by Δt, we get c (Ts -TI)yQ=W...-13
) Since the specific heat C1 and specific gravity γ of the fluid, the flow rate Q, and the electrical resistance of the heater 16 are known, if the temperature T1 is measured, the formula (
3), the desired constant temperature T is determined by the power calculation exit circuit 21.
The power W, generally the voltage, is calculated and the heater 16
It can be output to

Next, after the first temperature sensor 15a is exposed to the fluid at the inlet temperature T1 and the temperature is detected, until the heater 16 releases the thermal energy and transmits it to the outlet fluid, it takes a specific time period for the sensor and the heater. There is an inherent delay time t1 based on constants and fluids. For example, in the case of a sheathed heater, this includes the heat capacity of the electric resistor, the heat transfer resistance and heat capacity of the insulator and outer tube between the electric resistor and the outer tube, the heat transfer resistance between the outer tube and the fluid, etc. This is due to

By the way, an adjustment flow path 11 having a volume V is provided between the first temperature sensor 15a and the heater 16, and the adjustment flow path 11 is set so that the relationship between t6 and the flow rate Q is expressed by the following equation (4). Deploy.

V = Q - tk ... (4
) Therefore, even if there is the above-mentioned inherent delay time t7 that inevitably exists as a physical property, the first temperature sensor 15a
The fluid having a minute mass flow rate Δ- whose temperature is measured reaches exactly the position of the heater 16 after a time th, and receives the necessary heating corresponding to TI from the heater 16.

After all, even if the fluid whose temperature T1 fluctuates flows into the inlet 4 and there is an unavoidable delay tl in the heater 16, the heater 1
6 always captures a targeted microfluid, heats it with the necessary power W, and discharges the fluid at a desired constant temperature Ts.

In addition, since the control is performed using the temperature T1 upstream of the heater, it is a so-called feed-before, and the purpose is to match the timing, and to ensure that the power W is appropriate, that is, To is definitely TS. There isn't.

Invention 2 is based on the set intrinsic delay time tki set based on equation (4) in Invention 1 and the actual true intrinsic delay time t.

When there is a setting error time thd between
In a fluid where 1 is fluctuating, the above-mentioned difference becomes a phase difference and appears as uneven waves. It is not possible to accurately determine the time constants of sensors, heaters, etc., and even if they were known, Q and ■, especially Q
If there is a variation in , the principle of equation (4) of Invention 1 will not be utilized.

In Figure 2, Figure (a) shows the flow in the flow path, and there is an error or variation in grasping Q, V, or jha with respect to the true value shown by the - dotted chain line, and the set specific delay time thI is shown by the solid line. If so, when the minute mass flow rate Δ- reaches point B, which is g in front of the heater 16 at point A, the Z heater 16 will radiate heat corresponding to the temperature of 6 m at point B. ths
is excessive, ■ is large, Q is small, etc.

Figures (b) to (e) show the progression of the heat dissipation at appropriate times in correspondence with Figure (a).
In b), the steady temperature Ts flows in, the necessary heating W is performed at the heater point A, and the steady temperature To (aimed at Ts)
It flows out from the exit. Figure (c) shows the T! This shows the time when the fluid whose temperature is higher than ΔT reaches the inlet, and the fluid that has already flowed away is heated by To at the heater point A, similar to the diagram (b). Figure (d) shows the Ts+ΔT as explained in Figure (a).
This shows a situation in which the heater reacts prematurely at point A when the minute mass flow rate ΔT reaches point B, heating lower by -ΔT. The heating received from the heater at point A, where the peak ΔT in Figure (a) is not the original T++ΔT, but is treated as T1 and appears as To+ΔT in Figure (e). The above-mentioned To-ΔT exists in the distance of the trailing stream i. Therefore, in Figure (e), the second temperature sensor 15b is To-ΔT and To+
ΔT is measured. Although shown as distance i in the figure, the heater detects the corresponding time. The time corresponding to i in figure (e) and the time corresponding to g in figure (a) are
Considering the relationship that is inversely proportional to the ratio of the average cross-sectional area of each pipe section, the time corresponding to g can be calculated from the time corresponding to i, and th can be calculated. The error time calculation circuit 23 calculates these.

The term "error time calculation circuit that calculates the setting error time tha between the set specific delay time thI and the true value" in the section of the means related to the second invention corresponds to the above explanation. This effect is shown in [Figure (
It has the same meaning as "an arithmetic circuit that makes the time corresponding to i in e) zero," and includes the possibility of doing so. Furthermore, even if a plurality of fluids having ΔT continuously flow into the inlet and each pair of unevenness is detected by the second temperature sensor, the first temperature sensor detects ΔT and then the second temperature sensor detects the irregularities. 2
The time it takes for the temperature sensor to detect the unevenness is approximately fixed, so the detection of multiple ΔTs at the entrance and the second
The correspondence relationship between the unevenness in the temperature sensor is easily found. However, this becomes difficult when two ΔTs are detected in close proximity to each other at the entrance, but in reality, it is difficult to
Since most of the cases are due to OFF, etc., they are not detected in close proximity.

It is better to control Ehg based on a moving average of several control results.

Thus, the power calculation output circuit 21 via the delay circuit 22
True value. is input, and the heater heats the small mass flow path, which has a fluctuating temperature at the inlet, by precisely targeting it.

In invention 3, in invention 1 or 2, even if there is a slight variation in the flowing fluid, the fluid is mixed in the fluid mixing chamber 13 and the temperature is made more uniform.

In invention 4, in invention 1.2 or 3, the second temperature sensor 15b detects To, and feedback is performed via the feed bank circuit 24 for controlling To to Ts. Regarding feedback, it is a conventional technique.

〔Example〕

FIG. 1 is a pipe diagram of an embodiment, which is used by being connected to the cooling chamber 2 of FIG. 3, for example. FIG. 2 is a time chart diagram of FIG. 1.

In FIG. 1, a first temperature sensor 15a is provided at the inlet 4 of the conduit to measure the inlet temperature T1.

A heater 16 is provided at a distance 1 following the inlet 4 and across an adjustment channel 11 having a volume 2. A second temperature sensor 15 is located downstream of the second temperature sensor 15 at a distance f and measures the outlet temperature To of the pipe.
Further downstream, a fluid mixing chamber 13 equipped with an inverted U-shaped nozzle 12 is provided, leading to the outlet 8.

A power source 14 supplies power to the heater 1 via a temperature controller 20.
Supply to 6. The temperature controller 20 is a power calculation output circuit 2
1, a delay circuit 22, an error time calculation circuit 23, a field pack circuit 24, and a temperature setter 25 for setting a desired constant temperature Ts.

The first temperature sensor 15a and the second temperature sensor 15b are connected to this temperature regulator 20.

In such a configuration, first, the power calculation output circuit 21
The conditions for outputting power W will be explained.

When a fluid with an inlet temperature Ts flows in at a flow rate Q, if the specific gravity is T, the minute mass Δl at a minute time Δt is calculated by the following equation (1
) is given by

Δm=γQ・Δt...(11Δm
of fluid from temperature T1 to desired constant temperature Ts in time Δt.
The thermal energy required to raise the temperature to Substituting equation (1) and dividing both sides by Δt, we get C(TS −'r+ ”) rQ=W −...
(31 Fluid specific heat C1 specific gravity γ and flow rate Q and heater 1
Since the electrical resistance of 6 is known, once the temperature Ts is measured, the power calculation output circuit 21 calculates the power W, generally the voltage, to achieve the desired constant temperature Ts based on equation (3) and outputs it to the heater 16. can.

Next, after the first temperature sensor 15a is exposed to the fluid at the inlet temperature Ts and detects the temperature, until the heater 16 releases the thermal energy and transmits it to the outlet fluid, it takes a specific time for the sensor and the heater. There is an inherent delay time th that is unique to constants and fluids. For example, in the case of a sheathed heater, this includes the heat capacity of the electric resistor, the heat transfer resistance and heat capacity of the insulator and outer tube between the electric resistor and the outer tube, the heat transfer resistance between the outer tube and the fluid, etc. This is due to

Incidentally, an adjustment flow path 11 having a volume V is provided between the first temperature sensor 15a and the heater 16, and the adjustment flow path 11 is set so that the relationship between L1 and the flow rate Q is expressed by the following equation (4). Deploy.

V=Q-th (4) Therefore, even if there is the above-mentioned inherent delay time th that inevitably exists as a physical property, the minute mass flow rate Δm whose temperature at T+ is measured by the first temperature sensor 15a is The fluid reaches exactly the position of the heater 16 after the time tl and receives the necessary heating corresponding to T1 from the heater 16.

After all, even if the fluid whose temperature Ts fluctuates flows into the inlet 4 and there is an unavoidable delay th in the heater 16, the heater 1
6 always captures a targeted microfluid, heats it with the necessary power W, and discharges the fluid at a desired constant temperature Ts.

In addition, since the control is performed using the temperature Ts upstream of the heater, it is a so-called feed-before, and the purpose is to match the timing, and to ensure that the power W is appropriate, that is, To is definitely Ts. There isn't.

Next, the second temperature sensor 15b, the delay circuit 22, and the error time calculation circuit 23 calculate a set error time thd between the set inherent delay time ths set based on the above formula (4) and the actual true inherent delay time tha. This is automatically adjusted if there is a When thd exists, the above-mentioned difference becomes a phase difference in a fluid in which T1 fluctuates, and appears as uneven waves. The time constants of sensors, heaters, etc. cannot be accurately known, and even if they are known, the principle of equation (4) of Invention 1 cannot be utilized if there is a variation in Q or V, especially Q.

In FIG. 2, (a) shows the flow in the flow path, and Q, V, or deviation from the true value indicated by the dashed line. Assuming that there is an error or variation in grasping the set specific delay time ths as shown by the solid line, when the minute mass flow rate Δm reaches point B, which is g in front of the heater 16 at point A, the heater 16 Δ at point B
Heat radiation corresponding to the temperature m is performed. This is the case when ths is too large, ■ is large, or Q is small.

Figures (b) to (e) show the progression of the heat dissipation at appropriate times in correspondence with Figure (a).
In b), a steady state temperature Ts flows in, the necessary heating W takes place at the heater point A, and a steady state temperature 'ro (aimed at TS) flows out from the outlet. Figure (C) shows when the fluid higher than Ts by ΔT reaches the inlet, and the fluid that has already flowed away is heated by To at the heater point A, as in Figure (b). Figure (d) shows the TI as explained in Figure <a>.
A situation is shown in which when the minute mass flow rate Δm of +ΔT comes to point B, the heater reacts prematurely at point A and heats up by −ΔT lower. The heating received from the heater at point A where the peak ΔT in Figure (a) is not the original T1+ΔT but is treated as Ts and appears as To+ΔT in Figure (e). The above-mentioned To-ΔT exists in the distance of the trailing stream i. Therefore, in Figure (e), the second temperature sensor 15b has To-ΔT and T
o+ΔT is measured. Although shown as distance i in the figure, the heater detects the corresponding time. This figure (e
The time corresponding to i in ) and the time corresponding to g in figure (a) are calculated from the time corresponding to i to the time corresponding to g, considering the relationship that is inversely proportional to the ratio of the average cross-sectional area of each pipe section. You can calculate the time it takes to do this, and you can calculate tha. The error time calculation circuit 23 calculates these.

The term "error time calculation circuit that calculates the set error time t between the set inherent delay time thi and the true value" in the section of means related to the second invention corresponds to the above explanation. This action is shown in the figure (
It has the same meaning as "an arithmetic circuit that makes the time corresponding to i in e) zero," and includes the possibility of doing so. Furthermore, even if a plurality of fluids having ΔT continuously flow into the inlet and each pair of unevenness is detected by the second temperature sensor, the first temperature sensor detects ΔT and then the second temperature sensor detects the irregularities. 2
The time it takes for the temperature sensor to detect the unevenness is approximately fixed, so the detection of multiple ΔTs at the entrance and the second
The correspondence relationship between the unevenness in the temperature sensor is easily found. This becomes difficult when two ΔTs are detected very close to the entrance, but in reality, it is difficult to detect 0N-T in refrigerators etc.
Since most of the cases are due to OFF, etc., they are not detected in close proximity.

It is better to control jht based on a moving average of several control results.

(and then the power calculation output circuit 21 via the delay circuit 22
The true value jha is input to the heater, and the heater heats the small mass flow path, which has a fluctuating temperature at the inlet, by precisely targeting it.

And even if there is a slight fluctuation in the flowing fluid,
The fluids are mixed in the fluid mixing chamber 13 and the temperature is made more uniform.

Finally, the second temperature sensor 15b detects To, and feedback is performed via the feed hack circuit 24 for controlling To to Ts. Regarding feedback, it is a conventional technique.

In the embodiments described above, a bare thermocouple or an infrared sensor may be used as the temperature sensor, and a semiconductor circuit may be used for each circuit.

〔Effect of the invention〕

The constant temperature fluid supply device of this invention 1 includes a first temperature sensor that measures the inlet temperature Ts of the pipe, a heater downstream of the first temperature sensor, and a power W that increases the fluid to a desired constant temperature Ts. In a constant temperature fluid supply device comprising a power calculation output circuit that outputs output to a heater, an adjustment flow path having a volume of {circle around (2)} is interposed between the first temperature sensor and the heater, and the first temperature sensor and the The overall inherent delay time th of the heater and the flow rate Q flowing through the pipe
Regarding this, since V=Qx th is set, the power calculation output circuit applies a voltage corresponding to appropriate thermal energy to the heater based on the measurement value of the inlet temperature T of the adjustment flow path by the first temperature sensor. When outputting, even if there is a time delay th from temperature measurement to thermal energy release, the above T1
When the microfluid with a temperature of T reaches the T-degree heater, it releases thermal energy. Therefore, the heater always captures the targeted microfluid and provides the necessary heating.
This has the effect of providing a fluid whose outlet temperature To is kept low and close to the desired constant temperature Ts.

The constant temperature fluid supply device of invention 2 further includes: a second temperature sensor that measures the downstream outlet temperature To of the heater; a delay circuit connected before or after the power calculation output circuit; and a set specific delay time ths. and an error time calculation circuit that calculates the setting error time thd between the actual value and the true value, and the delay time tb of the delay circuit is adjusted so that the setting error time thd becomes zero. This has the effect of making the pulsation uniform.

In the constant temperature fluid supply device of the fourth aspect, feedback is performed based on the measurement result of Ts, and Ts is maintained accurately.

[Brief explanation of drawings]

FIG. 1 is a duct diagram of the embodiment, FIG. 2 is a time chart of FIG. 1, and FIG. 3 is a duct diagram of a conventional example. 1... Suction port, 3... Evaporator, 4... Population, 5.
15a. 15b... Temperature sensor, 6, 16... Heater, 11
... Adjustment channel, 12 ... Nozzle, 13 ... Fluid mixing chamber, 14 ... Power supply, 21 ... Power calculation output circuit, 22 ... Delay circuit, 23 ... Error time Arithmetic circuit. Figure 1

Claims (1)

[Claims] 1) A first temperature sensor that measures the inlet temperature T_1 of the pipe, a heater downstream thereof, and a fluid at a desired constant temperature T_s.
A constant temperature fluid supply device comprising a power calculation output circuit that calculates a power W to increase the power and outputs it to the heater, wherein an adjustment flow path having a volume V is interposed between the first temperature sensor and the heater. A constant temperature fluid supply device characterized in that V=Q×t_h regarding a total inherent delay time t_h of the first temperature sensor and the heater and a flow rate Q flowing through the pipe line. 2) In the constant temperature fluid supply device according to claim 1, a second temperature sensor that measures the downstream outlet temperature T_o of the heater, a delay circuit connected before or after the power calculation output circuit, and a setting-specific A constant temperature control device comprising: an error time calculation circuit that calculates a set error time t_h_d between a delay time t_h_s and a true value, and adjusts a delay time t_b of the delay circuit so that the set error time t_h_d becomes zero. Fluid supply device. 3) In the constant temperature fluid supply device according to claim 1 or 2,
A constant temperature fluid supply device, characterized in that a fluid mixing chamber is connected to an outlet of the pipe line. 4) In the constant temperature fluid supply device according to claim 1, 2 or 3, a feedback circuit is interposed between the second temperature sensor for measuring the downstream outlet temperature T_o of the heater and the power calculation output circuit. A constant temperature fluid supply device, characterized in that T_o is adjusted to the above-mentioned T_s.