JPH0370778B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to fluid sampling and has particular relevance to sampling for selected components of gases, primarily air.

Typically, the fluid sample collection to which this invention pertains involves the collection of hazardous components of the air within the facility under the Occupational Safety and Insurance Act (OSHA) in the United States or contaminated by chemical waste. air samples taken in areas such as Love Canel in the United States. This type of sampling is typically performed with a sampler carried or "worn" by a person who is exposed to the airborne harmful components. This sampling can be done either throughout the working day of the person involved or during measurement intervals. Sometimes it is also desired that the air flow through the sampler be restricted.

Some samplers include a pump that pumps air through a channel containing a collector or processor, and the instrument collects and/or measures the concentration of harmful components. The processor is usually placed in the inlet (suction side) to the pump. The processor is also used, especially in the case of chemical bag collection.
It may also be the outlet (pressure side). The components collected may be gases or vapors or solid particles. The sampled air contains dust, such as dirt or other debris, and it is necessary that such dust be filtered before entering the pump. The pump is protected by a so-called pump filter, through which the pumped air flows as it is drawn into the groove. The function of the pump filter is to protect the pump from this dust and debris. The filter assembly is loaded with dust during operation and provides a progressively higher pressure increase to the pump. Moreover, unless the effect of the filter assembly on the flow is compensated for, it will present an increasing impediment to the flow of air pumped through the grooves, and the speed or rate of air flow will decrease. do. Filter assemblies must be replaced from time to time to prevent improper operation. Flow may also fluctuate for reasons other than dust accumulation on the filter assembly. According to the prior art, a differential pressure switch is placed in the outlet of the flow passage to suppress air flow fluctuations. This pressure switch is
It responds to the difference between the pressure within one chamber and the pressure outside the chamber. This chamber is connected to the external area via a needle valve. The pressure switch opens and closes repeatedly in response to pulsations produced by the pumping action. One disadvantage of this measure is that repeated actuation of the pressure switch causes fatigue to its linkage. Another, more important disadvantage is that
Traces of dirt, such as dust, can interfere with the operation of the needle valve and prevent a satisfactory, stable, and reliable response to pressure pulsations within the flow groove of the switch. Another disadvantage is that additional pumping power is required to maintain the pressure required for detection, which
This is because the increase in pressure is absorbed to maintain control power.

One object of the present invention is to overcome the drawbacks of the prior art and to provide a fluid sampler that maintains a substantially constant flow of the fluid being sampled without fatigue of the moving parts. be.

In implementing sampling techniques, it is desirable to vary the flow selectively. That is, it is desired to vary the number of milliliters per second of fluid flowing through the sampler, particularly through the collector or processor.

(A) has the ability to sample fluid flowing through a collector at a selectively pre-regulated precise rate; and (B) has the ability to maintain the pre-regulated flow over a wide range of backpressures. It is another object of the present invention to obtain a sample collector that can be used.

In the prior art, pump assemblies were not easily accessible or visible. During use of such a sampler, the pump assembly
Eventually it becomes clogged, significantly impairing the operation of the collector and its reliability. Additionally, the pump assembly ceases to perform its filtration function and dust collects within the pump and inhibits valve operation. At that time, it is necessary to completely disassemble the collector, clean the pump, and replace the pump assembly.

It is another object of the present invention to eliminate this drawback of the prior art and to obtain a sampler in which the condition of the pump assembly is easily visible and the filter is easily accessible for replacement. .

It is yet another object of the present invention to provide a sampler in which the transport of moisture by the sampled fluid is eliminated.

One feature of the invention is that the fluctuations in flow through the sampler are due to the differential pressure, i.e., the output from the pump and the
Pressure difference between the inlet to the pump (hereinafter referred to as △
P) and the load on the motor that drives the pump. According to the invention, the motor is controlled in response to its load, ie, ΔP, to maintain the flow through the sampler substantially constant throughout its operating flow range.

According to another feature of the invention, the sampler is provided with a regulator integrated into its structure, which is inserted directly between the inlet and the outlet of the sampler. The regulator operates to circulate an amount of fluid in excess of the selected flow through the pump. Only selected streams enter the inlet and exit through the outlet.

According to still other features of the invention, a filter assembly is provided, the filter being encased in a container, the container having a transparent exterior at least upstream of the filter assembly. It has walls. The condition of the filter assembly can be observed through this wall. This wall is sealed to the rest of the container, but can be easily removed to allow access to the filter assembly. A fitting to a flow channel in the filter assembly opens at the top of the container. Moisture in the gas is settled into the bottom of the container.

In particular, the sampler according to the invention includes a compressed air mechanical unit including a pump, damper assembly, regulator, filter assembly and flow indicator.

The pump assembly is of the double acting type. The pump assembly is driven by a DC motor whose speed is controlled.

The damper assembly or damper consists of two silicone
It includes a compression spring sandwiched between the diaphragms, a housing, and necessary seals, and the damper rests directly on top of the pump assembly, with an intake air port connecting the damper to the pump intake. Do it like this. A through passage is provided in the damper body allowing the pump outlet to communicate with a pressure regulator superimposed thereon. A second damper can also be mounted on top of the first damper to improve damping, if required.

The regulator includes a cooperating sensing diaphragm, a spring, and a valve enclosed within a plastic housing that mounts directly to the top of the damper assembly and The inlet and outlet of the vessel are communicated with the suction groove and discharge groove of the pump, respectively. Means are included for disconnecting the suction side of the regulator. The regulator allows either suction or discharge to be pumped to maintain a nominal water column of 508 mm (20 inches).

The filter assembly includes a transparent housing with an air intake boss attached to the outside of the case. The front housing secures the filter membrane and seal O-ring to the rear housing (attached to the interior of the case) by four screws, thereby preventing air leakage from passing through. No seal is given. The rear housing is
Vertical risers are used to direct fluid into the fluid channels of the compressed air system. The transparent housing allows visual monitoring of the condition of the filter and water transport into the filter housing. In other words, the transparent housing allows the operator to view the pump assembly and determine when changes are needed. A riser inside the rear housing prevents water from entering the pump directly. Riser pipes are important in gas tanks;
Works together to trap moisture before it enters the pump. Moisture may damage the pump.

The flow indicator includes a rotary gauge mounted vertically in the exterior corner of the case to adjust the flow of the pump over the operating range, typically between 500 milliliters and 4 liters. used to indicate and instruct.

The sampler has an electronic solid-state controller that includes a current compensation circuit, a battery check, a battery low voltage indicator, a low current indicator, a timer, and an on/off switch. Contains.

The current compensation circuit provides a constant air flow from the pump over any preset flow range of the sampler, typically between 500 ml and 4 per minute. The compensation circuit is effective for pump linearity in conjunction with preloaded valves. The compensation circuit includes a sensing resistor mounted in the motor leg, which provides a voltage signal proportional to the motor load current to the power supply, and which itself also directs the motor voltage to the pump load curve. , which typically adjusts the water column (positive or negative) at flow rates over the operating range.
Provides relatively constant flow over a backpressure range of 0 to 40 inches (0 to 508 mm). An additional feature is automatic pump cut-off and failure indication should the pump become restricted (suction or discharge) beyond its operating range.

Equipped with visual battery check indicator
This is activated by a push switch for testing to detect battery overcharge conditions. The battery is typically a NICAD. Regarding battery capacity, there is a visual indication for a minimum of 8 hours of sampling at any current situation within the capabilities of the meter.

A visual low battery indicator is provided that will energize in the unlikely event that the voltage to the electronic controller drops below the minimum overvoltage required to properly operate the instrument. Ru. At the same time this indicator is energized, the pump and timer are stopped and the indicator is latched. The timer is stopped and indicates the number of hours of operation before the failure.

The low current indicator detects a no current condition, stops the pump and timer, and energizes the indicator after some suitable time delay that is a function of the overload condition.

A pre-adjustable electronic timer and indicator is provided to indicate the number of hours of operation, which is typically required to stop the pump.
Pre-adjustments can be made at 10 minute intervals up to 990 minutes (16.5 hours). The timing is adjusted by a 10 position switch, the first switch being 10
The second switch gives a 100 minute interval. The indicator is turned off until the test pushbutton is energized. The clock controlling the timer is automatically stopped when activated by any of the fault conditions mentioned above (specific current, low voltage, etc.). This feature allows the user to always achieve true sampling, even if the entire sampling period is not realized.

When power is applied, the on/off switch re-adjusts the counter to zero, puts the programmed time into the counter, automatically shuts off, and at the same time
Readjust all error latches to a non-fault condition.

In this regard, it seems desirable to explain the function of the regulator. The sampler can be operated either at normal full flow of fluid or at low flow under observation. The regulator is
Allows stable operation in low flow regulation of sampler. As mentioned above, the regulator is integrated with the collector and is interposed between its inlet and outlet, ie between the pump suction port and the pump discharge port.

When the regulator is regulated to a certain pressure difference, e.g. restraining means at the inlet or outlet of the collector;
or the water column with respect to the orifice as a restriction means.
When adjusted to 508 mm (20 inches), allows the sampler to provide constant flow multi-tube sampling. The flow across the orifice is a function of the differential pressure across the orifice. Thus, the orifice can be designed to provide the desired flow range if the pressure drop across the orifice is adjusted to the pressure for which the orifice is calibrated.

When activated, the pump flow typically
A flow of 1 per minute is regulated and a selected restriction orifice is inserted between the collector (single or manifold) and the inlet side of the pump.
The pump drops to 20 inches (508 mm) of water on the inlet side, which causes the pressure regulating valve to open and make up the flow difference from the pump discharge air. For example, if a 200 c.c. orifice is inserted between the sample collection tube and the inlet side of the pump, 200 c.c. will pass through the orifice and 800 c.c. Supplied from the pump discharge side via a regulator,
Return it to the pump at a rate equivalent to 1 per minute. The same concept can be applied on the discharge side, where a restriction orifice can be placed between the pump discharge port and the fluid collector (bag sampling). In this mode of operation, the pump pushes the discharge side up to 508 mm (20 inches) of water;
This causes the pressure regulator valve to open, diverting the flow differential to the pump inlet.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings showing embodiments thereof.

The illustrated apparatus includes a compressed air assembly 21 (FIG. 2), a battery pack 23, and a board 25 containing a printed circuit timing network (FIG. 7).
Sampler 20 includes a board 27 containing printed circuit control circuitry (FIG. 8). The sampler 20 has a casing including a front case 29 and a rear case 31. Battery pack 23 is a cartridge containing batteries 33 in a container 35. The front case 29 is
Its left hand end (as seen in Figure 1) is open,
It also includes a recess 37 on the left hand (as viewed in FIG. 1) and a slot 39 on the right hand. Timing network 25 and control network 27 include conductors that are interconnected (FIGS. 7 and 8) and extend vertically (as viewed in FIG. 1) and coextensive. I'm here. Boards 25, 27
The planar unit formed by the recess 3
It rests on a boss (not shown) extending from the back of 7. The battery pack 23 is installed behind the panels 25 and 27, and the battery 33 is installed behind the panels 25 and 27.
27, and battery socket receptacles 41 and 43 are connected to terminals or pins 45 and 47 (FIG. 8) of control circuitry 27. Name tag 49
is placed in recess 37 and adjacent thereto. A cover 51 extends into the recess 37 flush with the outer rim of the front case 29 and adjacent the name tag 49. The cover 51 has a tongue 53
This tongue 53 engages a cooperating groove (not shown) in the top of the recess 37.

Compressed air assembly 21 is supported in the right hand compartment (as viewed in FIG. 1) of front case 29. A flow meter 55 in compressed air assembly 21 is arranged opposite slot 39. A window 57 extends into the slot 39 between the flow meter 55 and the slot 39, with a stepped frame of the window 57 bordering the slot 39.

The top of the compressed air assembly 21 has a hollow boss 6
1,63,65. insert 67
extend over the bosses 61, 63, and 65 and are arranged on the top. Insert 67 has a tongue 69 that engages a groove (not shown) in the edge of slot 71 in the top of front case 29. Rear case 31 surrounds compressed air assembly 21 and its inner edge engages the inner edge of front case 29 . The inner edge of the rear case 31 is provided with a tongue 73 which engages in a slot (not shown) in the inner edge of the front case 29.
The rear case 31 is fixed to the front case 29 by screws 75 passing through bosses in its four corners. The rear case 31 has a slot 77 in its top, into which the case 31 engages the insert 67. The inner edge of slot 77 has a groove 79 that connects to a tongue (not shown) in insert 67. The rear case 31 has a slot 81 in its side which surrounds the inner boundary of the pump filter assembly 83.

A belt clip 85 is secured by a rivet 87, which is attached to the rear case 3.
1 through the hole 89 near the left hand edge. Belt clip 85 extends beyond the left hand edge of rear case 31 and bounds a vertical space or pocket for receiving battery pack 23.

In assembling the sampler 20, the compressed air assembly 21 first secures the rear case 31 to the front case 29, places the window 57 into the slot 39, and inserts the right hand compartment of the front case 29. and the rear case 31. Belt clip 8
5 is secured to the left hand end of the rear case 31 to provide a pocket or slot between the clip 85 and the left hand side of the front case 29. Boards 25 and 27
The planar unit formed from the recess 37
is secured to a boss (not shown) on the back of the. Battery pack 23 is slipped through the left hand open end of front case 29 into a pocket between the back of front case 29 and belt clip 85. The tongues 91 in the upper and lower ends of the battery container 35 engage grooves (not shown) in the rear of the front case 29. The battery pack 23 is
The pins 45 and 47 (FIG. 8) are slid along the flat circuit units 25-27.
into the sockets 41 and 43 so that they are fully inserted into the final position of the battery pack 23. A step 92 in the base of the container 35 of the battery pack 23 is dovetailed with a projection (not shown) in the base of the compressed air assembly 21.

The external dimensions of a typical sampler according to the invention are as follows. The length (measured horizontally along the screen with respect to Figure 1) is 1017mm
(4-5/8 inches), depth (into the screen in Figure 1), 33.4 mm (1-5/16 inches), height (vertical in Figure 1), 127 mm (5/5 inches), inch). Total length is 12.7mm (1/2 inch) for filter 83
and the total depth is 85 mm.
Contains 6.4mm (1/4 inch) for.

The compressed air assembly 21, as shown in FIG.
In addition to ROTOMETER 55 and pump filter 83, it includes pump assembly 93, damper assemblies 95, 97, and regulator 99.
Pump assembly 93, damper assemblies 95 and 97 and regulator 99 are stacked and together fit into hole 10.
1 through screw 96. In the stack, the pump assembly 93 is located at the top 114.
and the upper valve plate 120 and between the bottom plate 116 and the lower valve plate 122.
Contains. Each assembly 93, 95, 97, 99
are held together in countersunk holes 104 by screws 102 (Figures 3, 4, and 5). Pump 93, damper assemblies 95, 97, and regulator 99 have coextensive openings that, when these parts are stacked, are in the suction groove 106 (sixth
), through which air is pumped into the compressed air assembly 21. Components 93, 95, 97 and 99 also include discharge groove 1.
08, but when these assemblies are stacked, these grooves 108
Air is then discharged from the compressed air assembly.
As shown in FIG.
Also, the groove 108 is connected to the boss 63, respectively.
It is coaxial. The openings forming grooves 106 and 108 in the pump assembly, damper assembly and regulator are connected to mating parts 93 and 95, 95.
and 97 and between each pair of 97 and 99 are sealed by compressed O-rings 110 and 112.

Filter assembly 83 is best shown in FIG. This assembly 83 includes the front housing 1
03 and a rear housing 105. At least the front housing 103 is transparent and has a fitting 107 for receiving a fluid sample. Rear housing 105 has an upper tongue 109 and a lower tongue 111. The upper tongue 109 engages a slot (not shown) in a protrusion 113 extending from the lower plate 115 of the regulator 99 through which air passes through the compressed air assembly 21. It is pumped out through the pump.
The lower tongue 111 is connected to the upper valve plate 1 of the pump assembly 93.
20 engages with the groove 117 in the protrusion 118. In this manner, filter assembly 83 is suspended from the body of compressed air assembly 21. An annular projection 119 extends from the surface of rear housing 105 facing front housing 103 . The outer surface 121 of this protrusion 119 is beveled inwardly at an angle of approximately 45 degrees. An O-ring 123 and a filter 125 are sandwiched between the beveled surface 121 of the annular body 119 and a recess (not shown) in the front housing 103. When housings 103 and 105 are secured together by screws 127, O-ring 123 is compressed between chamfered surface 121 and the rim of the recess (not shown), and one It seals the chamber bounded between the filter 125 and the recess on one side and between the filter 125 and the rear housing 105 on the opposite side. Mounting tool 107
is in communication with the recess and therefore filter 1
The inhaled air is sent through 25. Filter 1
25 is clearly visible through the front housing 103.

An outlet tube 129 is sealed through the lower wall of rear housing 105. This tube 129 is
It passes through the annular body 119 and opens inside the annular body 119 near the top of the rear housing 105 . The air passing through filter 125 is
Before exiting via 9, it must be pushed to the top of the chamber bounded by annulus 119. Water droplets or vapors in the air are deposited into the lower region of this chamber. The tube 129 is a flexible tube 131
is connected to the inlet 133 of the flow meter 55 by.
Outlet 135 of flow meter 55 is connected via tube 137 to inlet 139 into protrusion 113 . Filtered air is thus drawn through the compressed air assembly 21.

The pump assembly 93 (FIG. 3) includes the upper valve body 12
In addition to the lower valve plate 122, the top plate 114, the bottom plate 116, and the gaskets 98, 100, the main body 149 has a rectangular parallelepiped shape. This main body 14
9 has a horizontal recess 151 into which an eccentric drive body 153 extends. This driving body 153 includes a motor 155 and an eccentric 157 driven by the motor 155. The eccentric 157 is an eccentrically placed pin 1.
59, this pin 159 is
It can rotate freely inside 61. motor 155
is secured in the recess 151 by a set screw 163.

Body 149 also has a vertical bore 165 extending through the top and bottom of body 149;
Further, this inner hole 165 communicates with the depression 151. A diaphragm assembly 167 is mounted within the vertical bore 165 . This assembly 16
7 is a yoke 168, upper and lower diaphragms 169, 171, a diaphragm holder 173,
Contains 175. Diaphragm 169 and 1
71 are end plates 177 and 179 of the yoke 168;
are engaged by retainers 173 and 175. The diaphragms 169 and 171 are connected to the main body 14
An annular recess 181 in the top and bottom of 9 (third
(Fig.). Those diaphragms are
It is held within this recess 181 by an upper valve plate 120 and a lower valve plate 122. A pin 159 and bearing 161 extend into an opening in yoke 168, with bearing 161 engaging a surface bounding the opening. Pin 159 is connected to motor 155
When rotated by , yoke 168 is moved upwardly and downwardly, correspondingly deflecting diaphragms 169 and 171 upwardly and downwardly in opposite phases. Main body 149 and upper and lower valve plates 1
O-ring seal 183 between 20 and 122
(Fig. 6), these seals have inner hole 1
Seal 65.

Upper valve plate 120 has a circular opening opposite diaphragm 169 and is sealed by diaphragm 169 . diaphragm 16
9 and upper valve plate 120 form a filling chamber 187 (FIG. 6) at the opening. Upper valve plate 12
The base of this filling chamber 187 in 0 has disk-shaped depressions or valve seats 189 and 191 (FIG. 6). Within each recess is a prestressed valve plate 193 and 195 (best shown in FIG. 6). Each valve plate is secured and prestressed in its recess by a retainer 197 that engages a spacer 198 on the opposite side of the valve plate. Valve seat 189
and 191 there are holes 199 and 201. Holes 199 connect the filling chamber 187 to the suction groove 106, and holes 201 connect the filling chamber 187 to the discharge groove 106.
Connect to 8. This connection is through hooked slots 203 and 205 in the upper valve plate 120. The valve plate 193 is connected to the diaphragm 16
9 is positioned to release its valve seat 189 when it moves downward, creating a partial vacuum in the plenum chamber 187. Against this tendency of the diaphragm 169, the other valve plate 195 is forced into tighter engagement with its valve seat 191. Conversely, diaphragm 169 is moved upwards, filling chamber 187
When increasing the pressure within, valve plate 195 opens and valve plate 193 closes more tightly.

The lower valve plate 122 likewise has a circular hole 207, which is sealed by a diaphragm 171 to form a filling chamber 209 (FIG. 6). The base of the filling chamber 209 has a circular valve seat 2.
11 and 213, and above them,
Valve plates 215 and 217 are placed. Valve seat 211,
213 connects the filling chamber 209 to the slot 223 (sixth
It has holes 219 and 221 which are connected to the suction groove 106 via a slot 225 (see Figure) and to the discharge groove 108 via a slot 225. The main body 149 is
Suction groove 1 through oval slots 226 and 228 sealed by O-ring 183.
06 and the discharge groove 108.

Pressure switch S3 (Figs. 6 and 8) is connected to the bottom plate 116.
suspended from. This switch S3 has a suction slot 223 on one side;
Also, on the other side, the ejection slot 22
5, which actuates latch 4U3 (FIG. 8) in response to both excess vacuum on the suction side and excess pressure on the discharge side, e.g. The operation is stopped under conditions that require it to be stopped, such as when the machine is clogged.

Each damper 95 and 97 (FIG. 4) has a damper body 231. This damper body 231
has a vertical circular bore 233. Inner hole 23
3 has a flexible diaphragm 235 at both ends.
and 237. Diaphragm 2
35, 237 are connected to the main body 2 in their periphery.
an annular recess 239 in the opposing surfaces of 31;
The bottom plate 243 and the top plate 241 engage with each other. Each plate 241 and 243 has a circular recess 245 in its inner surface. Top and bottom plates 241 and 243 each have a slot 247 in their outer surface;
These slots 247 communicate with recesses 245. The outer surface of each diaphragm 235 and 237 is thus under atmospheric pressure. The pressure on the outer surfaces of diaphragms 235 and 237 is relieved by springs 249 that apply pressure on each of the diaphragms. A hole 251 is drilled through the wall of the main body 231;
51 passes through the hole 106D of the main body 231 located in the suction groove 106, and also passes through the hole 233.
This hole 251 connects the suction groove 106 to the recess formed between the diaphragms 235 and 237 and the inner bore 233. The outside of the hole 251 is closed by a plug 253. Pump assembly 93
When the is operated, a pulse of air is drawn into the groove 106. These pulses also
1 into a recess bounded by diaphragms 235 and 237 and bore 233, and spring 249 and diaphragms 235, 237.
, producing a pulse that is out of phase with the pulse flowing into groove 106 . The pulses flowing through grooves 106 and into filling chambers 187 and 209 (FIG. 6) are thus smoothed. The diaphragms 235, 237 and the spring 249 act similar to capacitive inductive filters in parallel with a current load corresponding to the pressure within the plenum 187, 209.

Regulator 99 (FIG. 5) includes a top plate 255 in addition to bottom plate 115. The bottom plate 115 is the second
It has a cylindrical recess 257. Padded 25
A 9-shaped valve seat is arranged in the recess 261 in the base of the recess 257. Top plate 255 also has a first cylindrical recess 263 (FIG. 6). A deflectable diaphragm 265 rests with its edges in engagement with an annular recess 267 bounding recess 257. diaphragm 26
5 is held between the top plate 255 and the bottom plate 115. A flanged hollow valve 269 extends through an opening 270 in the center of diaphragm 265 . The valve 269 is secured by a retainer washer 271 and the inner edge of the diaphragm 265 is secured above the top by a valve flange 273.
It is also engaged on the bottom by a retainer washer 271. Valve 269 has an externally tapered tip. Valve 269 has an internal shoulder on the tip. A spring 275 (FIG. 6) engages the shoulder at its lower end and extends into a hollow projection 277.
is coaxial with the hollow boss 61 extending from the top plate 255, and also engages the end of the screw 279 in the top plate 255. The head of the screw 279 is threaded and is engaged by an internal thread 281 at the top of the hollow boss 61. Screw 279 is threaded or unthreaded to compress or loosen spring 275 as required. Spring 275 causes the tip of valve 269 to engage valve seat 259 . In this way, the valve 269 and the valve seat (pad) 259 constitute a valve means. The hollow boss 65 is coaxial with and communicates with the suction groove 106. The hollow boss 63 of the top plate 255 is coaxial with and communicates with the discharge groove 108.
This boss 63 has a horizontal hole 280. In operation where the collector is placed on the suction side,
Air passing through the discharge or pressure groove 108 is vented into the housing for the sampler via an internal hole 280. The housing is substantially airtight and the increased pressure prevents debris from entering the housing. Boss 63 is internally threaded and is adapted to receive fitting 287 (FIGS. 5 and 6). This fixture 287
The inner rim of the O-ring 288 (FIGS. 5 and 6) engages the hole 280 to seal the hole 280 against passage of exhaust air. The fixture 287 is used in bag collectors or other similar operations, where the collector or meter is fitted with a bag (not shown) or the like placed on the discharge side. , coupled to receive exhaust air through fitting 287.

The horizontal hole 283 serves as the first flow path means, and the top plate 255
It is opened through the top plate 255 and communicates with the opening 106R of the suction groove 106, and
Extends into 3. This hole 283 has a plug 285
occluded by The suction groove 106 is thus connected to the recess 263. screw 29
0 is provided to seal the connection between the suction groove 106 and the recess 263. This screw 29
0 passes through boss 65 and engages internal threads in top 255. The screw 290 has a tip 289 at its lower end;
It engages with the O-ring 110R and prevents connection. Lateral holes 291 and 293 are drilled through the body of the bottom plate 115 and the protrusion 113. A lateral hole 291 extends into the suction groove 106 at the opening 106R. A lateral hole 293 as a second channel means passes through the discharge groove 108 at the hole 108E and extends into the recess 257. hole 291
and 293 are occluded by plugs 295 and 297. Hole 291 connects flow meter 55 to the suction groove. (Figure 6 shows that in this feature,
it's not correct. ) Instead of being connected directly to hole 291, inlet 139 extends into projection 113 (FIG. 5) at right angles to hole 291. Entrance 1
39 (FIG. 2) communicates with hole 291. The location of hole 291 is shown in FIG.

In operation of regulator 99, screw 290
is pivoted upwards, thereby causing depression 263
is connected to and at the same pressure as the suction groove 106. The force of spring 275 applied to maintain valve 269 closed causes recess 257 to be connected to and under pressure of the drain groove;
It is relieved by the pressure difference between the depression 263 and the depression 263. When the flow of air into the fitting 107 for receiving a fluid sample into the front housing 103 is restricted by the orifice 299, the pressure between the atmosphere and the inner end of the orifice 299 There is a difference. Typically, pump assembly 93 is adjusted to run at 1 per minute and the flow through orifice 299 is 1 per minute.
Adjusted to 200ml per minute. While the pressure inside recess 257 remains at atmospheric pressure, recess 2
The air in 63 is then exhausted. screw 2
79 compresses spring 275, thereby causing valve 269 to open due to the pressure differential created. Exhaust gases are then partially
pumped through the boss 63 and also partially includes the groove 108, the hole 293, the valve 269, the hole 283,
It is pumped out via a closed circuit containing a suction groove 106 and via a pump. Due to the differential pressure between the appropriately adjusted recess 257 and the recess 263 and due to the pump being adjusted to 1 ml per minute, 200 ml per minute flows out through the boss 63 and 1 ml per minute. 800 ml per minute circulates through the closed circuit described above.

The compressed air assembly 21 is electrically controlled by a timer board 25 and a control board 27. The actual circuitry that operates satisfactorily is the 7th one for the timer.
The control circuit is shown diagrammatically in the figure and in FIG. 8, respectively. These networks mostly include integrated circuits. The parts of the integrated circuit included are indicated by their trade names and their pin numbers are indicated. For example, operational amplifiers U1-3U1, as labeled, are part of a 399 integrated circuit. The actual size of the parts is also shown. If the size of the capacitor is indicated only by numbers, for example, in Fig. 7, the capacitor C
For 1. If it says 001, the capacity is micromicroquarads (picofuarados).
The size of the microfarad is named accordingly. The size of the resistance is ohms, 1000 ohms with a "K" in the number, and "M" in the number.
is attached. It is 1 million ohms. For the most part,
The magnitudes of the input and output signals are indicated numerically as 1 or 0 instead of high and low. 1 is
2.4V and higher, 0. 4V and lower. However, sometimes an intermediate state exists at about 2.5V, in which some operation is possible. The output on the control panel 27 and the input to the timer panel are named TIM, etc. A bar above an input, for example a bar above TIM, means that a 0 is applied, producing the desired effect. If there is no bar, for example, INH is applied with a 1, producing the necessary effect and resetting in this case. Since the sampler container is constructed from electrical insulation, grounding is provided by conductors on printed circuit boards 25 and 27. Power grounding is normally done by three wires GD of decreasing length.
It is expressed by. Digital grounding is represented by the fork-shaped symbol GRD.

The device shown in FIG. 7 includes an oscillator OSC, a frequency divider U2, typically 14 stages (divided by 10 ¹⁴ ), a counter U3 and a display U4. The oscillator OSC includes an operational amplifier U1, a calibration resistor R6, a resistor RP1 and a capacitor C1. The period is typically about 366 microseconds. The output of the oscillator OSC is applied onto the clock input CK of the divider U2. At its output O14, the divider U2 produces a low frequency signal, typically one cycle every 6 seconds. This signal is applied onto the clock input CK of counter U3. The number of counts produced by counter U3 is preset by selection switches S1 and S2. S1 can count 100 and S2 can count 10. Switches S1, S2 operate via diodes CR1-CR8. Counter U3 includes a register and a comparator (both not shown).

At the start of operation when power is first applied, the input LR of U3 goes to 1 from the 5V supply via capacitor C3. When capacitor C3 is charging, input LR will be 2.5V. Finally, capacitor C3 is sufficiently charged and LR becomes zero. When LR becomes 1, switch S
The numbers adjusted by 1 and S2 are loaded into the register of U3. Reset output RES
is adjusted to 0 and counting begins after LR reaches 2.5V. Counting continues with LR at or below 2.5V. When the comparator finds that the input count is equal to the count stored in the register,
EQ goes to 0 and latch 1U3 (FIG. 8) is adjusted, producing a 1 at inhibit gate INH. The output of amplifier 1U1 (pin 13) goes to 0, stopping the oscillator OSC and stopping counting. Motor 155 is also stopped. In each latch, the setting produced by a 0 in is latched in and after the 0 is released from the latch, it is latched in until a 0 is applied above to reset the latch. It will remain. By setting LR to 0, U4 is emptied. The signal above TST produced by closing switch 1S2 (FIG. 8) activates display U4. The display is performed on the display U4 via the outputs a to g of the counter U3 and the inputs a to g of the display U4.
Applied from counter U3. U3 output D0~
D4 transfers the displayed digits via inputs D0-D3 of U4. D3 is the most important number,
D0 is the least important number. The decimal point is
With test TST set to 1, it is drawn out via operational amplifiers 2U1 and 3U1. When D1 is 1, there is no decimal point. When D1 is at 0, there is a decimal point.

FIG. 8 shows the motor controller MC for motor 155 near its center. The remainder of Figure 8 shows the display and protection circuitry. The apparatus shown in FIG. 8 includes a regulator 1U2, which produces a reference voltage at its output. Typically the output is 2.6V for any battery voltage above 4.3V. A reference voltage of 2.6V is applied to selected points in the circuit shown in FIG.

The motor controller MC is responsive to the motor load and maintains a constant air flow, ie, ml per minute or ml, as air is pumped through the compressed air system. In this controller, motor 15
5 is supplied via transistor Q1. The motor current is passed through the emitter and collector of Q1, the motor,
Flows to ground via resistor R11. The current through resistor R11 is substantially equal to the motor current. Filter R12-C4 introduces a delay into the controller;
Prevents unwanted tripping of overcurrent detection circuits due to transients. Capacitor 1C3 across the motor
but suppresses brush noise. The device is switch 1
It is energized with S1 in the "on" position. With switch 1S1 in the "off" position, C4 is discharged to ground. Transistor Q1 is controlled by operational amplifier 4U1, the output of which is connected to the base of Q1 via resistor R7. The resistance R6 between the emitter of Q1 and the output of 4U1 is
Make sure that when it should be cut off, it is cut off completely. Q1 collector and 4U
There is a feedback network between the positive input of 1 (pin 5). This network includes resistor R8 and networks R4, R23 and R5. R23
is a thermistor whose resistance varies exponentially with temperature. R4 linearizes the response of R23. Networks R4, R23, and R5 change resistance proportionally to temperature changes, compensating for resistance variations with temperature of the copper in motor 155. Capacitor C2 is responsible for the response of the controller to load variations, ie, to airflow variations. Introduce a 3 second delay. Network R8, R4, R5, R23 adjusts the gain of amplifier units 4U1-Q1.

Control for the amplifier unit is provided by network 1R1, from the 2.6 output of 1U2 on top of the negative input of 4U1.
1R2, R9, R22, R10, R11 and R3
is applied. Resistor R11 for measuring motor current
The drop across resistors 1R1, 1R2, R9, R
22 and the voltage drawn through R3. R3 adjusts the desired airflow and 1R1
is adjusted for correction at the high end, and 1R2 is adjusted for correction at the low end.

The circuit disclosed herein can track changes in current without becoming unstable. When the current changes, the drop across R11 changes and compensates for the change in current by changing the terminal voltage applied to the motor. If the current is increased above the regulated magnitude, the drop across resistor R11 decreases, reducing the terminal voltage across the motor, and if the current increases above the regulated magnitude. If it decreases below, the drop across resistor R11 increases, increasing the terminal voltage.

A comparator in U3 signals the end of counting, and when there is a zero above, the entered count is equal to the preset register count;
There is a 0 above TIM. Latch 1U3 is adjusted to input S and a 1 is placed on output Q.
The current is light emitting diode (LED) 1CR4, R4
and flows to ground via R23. There is a 1 above the positive input 5 of 1U1. The current through motor 155 is cut off and pump 93 stops pumping. The light in LED1CR4 seen by the driver indicates the end of counting.

For normal operation of motor 155, resistor R1
The current through 1 is no greater than some predetermined magnitude, typically 200 milliamps. Note that this magnitude has been assumed for the purpose of illustrating the operation of the apparatus shown in FIG. 8 in the case of excessive motor current. Based on this assumption, the voltage on pin 10 of 5U1 is approximately . It is 3V. If the resistor R11
But if it draws more than 200 mA,
The voltage applied across pin 9 of 5U1 through resistor R12 is . Above 3V, there is a zero on the output of 5U1 (pin 8) and the input of latch 2U3. Above the Q output of 2U3 and diode 1CR1
1 is on the conductor 301 passing through. Diode 1CR1 is energized to indicate overcurrent. 1 is on the conductor 303, and the motor 15
Stop 5. There is a 1 on the output terminal INH, ie the inhibit gate. The oscillator OSC is deenergized (FIG. 7) and counting by U3 is stopped. An indication of the count before the oscillator OSC is de-energized is available and gives information on how long the sampler was activated before an overcurrent occurred.

Three conditions cause the output of amplifier 6U1 to be zero.

1. The voltage of battery 33 drops to about 4.3V or less. This condition is monitored by a voltage divider including resistors R18, R19, and R20. Typically, these resistors apply a voltage of 2.6V or more on pin 12 of 6U1. If the voltage on battery 33 drops below about 4.3V, the voltage on pin 12 drops below 2.6V, the output of 6U1 goes to 0, and latch 4U3 is latched. LED, LCR2 is energized, 1 is conductor 30
1, applied to the conductor 303 and the output terminal INH,
Motor 155 is stopped and oscillator OSC is deenergized.

2 If Q1 is unable to supply sufficient current to satisfy the circuit requirements, then for normal operation the output of amplifier 4U1 (pin 7) will be approximately 1.9V. be. Current flows through the emitter and base of Q1. The drop across diode 1CR5 is approximately 0.7V, so pin 12 of 6U1 is at 2.6V (1.9+.7)
It is. There is a 1 above the output of 6U1. If the voltage at the output of 4U1 is below 1.9V, 1CR5 conducts and pulls pin 12 of 6U1 below 2.6V, causing the output of latch 4U3, conductors 301 and 303 and the output INH
1 is on the top, and the motor 155 and oscillation cutoff
Stop OSC.

3 Activation of pressure switch S3. In this case, 6
Pin 12 of U1 goes to 0 and output of 4U3 goes to 1
Therefore, the motor and oscillator are stopped.

Network R24-C8 is a delay network that blocks surges from trip latch 4U3.

Latch 3U3 operates to reset the device at the beginning of operation. Normally, the adjustment input is grounded and the output Q is 1. At the beginning of operation when power is first applied, capacitor C5 operates as a short circuit and R is zero.
The latch is reset and its output is zero. There is a zero on conductors 305 and 307. Latch 1
U3, 2U3 and 4U3 are reset and output
There is also a 0 above RES, which resets the timer.

At full battery voltage, ie 5.3V, voltage divider R18, R19, R20 applies a higher voltage of 2.6V or more on pin 2 of amplifier 7U1. The output of this amplifier 7U1 becomes 0. When test switch 1S2 is activated, the current is 1CR
3, indicating that the battery is fully charged. There is also 5V above the output TST. R
8 (FIG. 7), 2-1/2V is applied onto input LR of counter U3.

Although preferred embodiments of the invention have been described, many modifications thereof are possible. Therefore, the present invention
It should be understood that this example is not limiting.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing one embodiment of the present invention;
1A is a front view of the embodiment of FIG. 1 with the top cover of the name tag removed; FIG. 2 is an exploded perspective view of the air assembly of the embodiment shown in FIG. 1; FIG. 2A is a front view of the embodiment of FIG.
1A is a partial vertical sectional view showing the transparent pump filter housing of the device shown in FIG. 1A; FIG. 3 is an exploded perspective view showing the pump incorporated in the embodiment shown in FIG. is an exploded perspective view showing the damper incorporated in the embodiment shown in FIG. 1, and FIG.
FIG. 6 is a partially schematic longitudinal cross-sectional view of the compressed air assembly; FIG. 7 is a timing circuit incorporated in the present invention; FIG. The schematic diagram, FIG. 8, is also a schematic diagram of the control circuit. 20... Sample collector; 21... Compressed air assembly; 22... Battery pack; 25... Timing circuit network board; 27... Control circuit network board; 29, 31...
Casing; 33...Battery; 35...Container; 37
... hollow; 55 ... flowmeter; 61, 63, 65
... Boss; 79 ... Groove; 83 ... Filter assembly; 93 ... Pump assembly; 95, 97 ... Damper assembly; 99 ... Adjuster; 103, 105 ...
Casing; 106... Suction groove; 107... Mounting tool; 108... Discharge groove; 120... Upper valve plate; 122... Lower valve plate; 125... Filter;
129... Outlet pipe; 167... Diaphragm assembly; 169, 171, 235, 237... Diaphragm; 193, 195... Valve plate; 211, 21
3... Valve seat; 215, 217... Valve plate; 259...
...Putsudo.

Claims (1)

Claims: 1. A liquid sampler 20 including a compressed air assembly 21 consisting of a pump assembly 93 and a regulator 99, the compressed air assembly 21 having a suction groove 106 and a regulator 99. The filter assembly 83 can be connected to the suction groove 106 on its inlet side or to the discharge groove 108 on its outlet side. The pump assembly 93 is driven by a motor 155 to suck a fluid sample into the suction groove 106 and guide it through the discharge groove 108 and into the fluid guide groove. The fluid guide channel also includes a restraining means 299 for restricting the flow rate of the fluid sample therethrough to a lower flow rate than the flow rate of the fluid sample caused by operation of the pump assembly 93. is provided, thereby causing a pressure difference to be created in the fluid conduit across the restraining means 299, furthermore, the regulator 9
9 indicates the suction groove 106 and the discharge groove 10.
8, each has a first passage means 283 and a second passage means 293 and valve means 269, 259, which are directly connected to each other, and the valve means 269, 259 are connected to the suction groove. 106, the pump assembly 93, and the discharge groove 108,
The discharge groove 108 and the second flow path means 29
3, the first flow path means 283, and the suction groove 106,
Furthermore, the regulator 99 ensures that when the pressure difference exists, only the fluid sample directed through the suppression means 299 flows through the suction groove 106 and the discharge groove 108, and the pump assembly 93
The fluid sampler is adapted to be connected to the closed circuit such that a remainder of the fluid sample aspirated by the pump assembly 93 and the regulator 99 circulates through the pump assembly 93 and the regulator 99. 2. The fluid sampler of claim 1, wherein the regulator 99 is structurally integrated with the pump assembly 93. 3. The pressure regulator 99 is connected to a first cylindrical recess 263 and a second cylindrical recess 257, a diaphragm 265 bounding the first and second cylindrical recesses 263, 257, and said first passage means 283 connecting said cylindrical recess 263 to said suction groove 106 and said second passage means connecting said second cylindrical recess 257 to said discharge groove 108. means 293 and said valve means 269 interposed between said first cylindrical recess 263 and said second cylindrical recess 257;
259. The fluid sampler of claim 1, comprising: 259. 4. said valve means 269, 259 comprising a hollow valve 269 interposed in said diaphragm 265 and a pad 259 in one of said cylindrical recesses 257 cooperating with said hollow valve 269; The pad 259 is connected to the second cylindrical recess 25.
7 and the first cylindrical recess 263 is lower than the pressure difference generated by the restraining means 299, the diaphragm 265 engages the hollow valve 269. The hollow valve 269 is pushed forward and the pressure difference between the second cylindrical recess 257 and the first cylindrical recess 263 causes the restraining means 2
65, the diaphragm 265 is adapted to be forced out of engagement with the pad 259 when the pressure difference is equal to or greater than the pressure difference generated by the diaphragm 265. The fluid sampler according to paragraph 3. 5. Fluid sampling according to claim 3 or 4, including a spring 275 for applying a selected pressure to the diaphragm 265 to set the pressure differential at which the valve means 269, 259 open. vessel. 6. The motor 155 for driving the pump assembly 93 and the motor 155 are configured such that the flow rate of fluid between the suction groove 106 and the discharge groove 108 is maintained substantially constant. A timing circuit network 25 and a control circuit network 27 are connected to the motor 155 for control.
A flow rate sampler according to claim 1, comprising: