JP2001027618A - Radioisotope moisture meter for concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radioisotope moisture meter for concrete capable of being attached to a profile diameter pump piping and capable of excluding the generation of fluctuations in a measured value and the adverse effect due to noise. SOLUTION: A radioisotope moisture meter consists of a parallel crosses- shaped rigid frame part 1 freely developed and closed so as to be capable of being mounted on a pump piping 5 having different diameters, the graspable clamping jig attached to the rigid frame part 1, the neutron ray source 9 emitting a fast neutron freely detachable to the upper and lower opposed sides of the rigid housing part 1, the pump piping 5 and a detection pipe 10 for counting the fast neutron transmitted through concrete in the piping 5 and the neutron ray source 9 and the detection pipe 10 are held to constant positional relation regardless of the diameter of the pump piping 5 by a change in the grasping angle of the clamping jig to be fixed to the pump piping 5 and the amplifier in the detection pipe is fixed in a three-dimensional state enveloped by a viscoelastic material such as urethane sponge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the total amount of concrete passing through a pump pipe in order to control the quality of water by measuring the amount of water in concrete when placing concrete using a concrete pump. The present invention relates to improvement of a radioisotope moisture meter for concrete that measures moisture content in real time.

[0002]

2. Description of the Related Art Various methods have been tried as a quality control method for measuring unit water amount of concrete to be poured, which makes it possible to estimate quality such as strength of hardened concrete in advance. And a method such as a high-frequency heating drying method and an underwater mass method, which are performed by collecting a sample. However, these methods require a lot of sampling time,
In addition, there is an unsuitable problem in that it is only a representative value of a part of the sample and cannot be measured for the entire amount of concrete to be poured (continuously and continuously).

On the other hand, a radioisotope moisture meter can measure the moisture content of a target sample in a non-contact state, and can display the measurement result in real time. Therefore, if the radioisotope moisture meter can be attached to the pipe of the concrete pump, it becomes possible to measure the unit water amount for the entire amount of concrete flowing in the pipe under the above-mentioned conditions.

The radioisotope moisture meter is mainly detected by a neutron beam source that emits fast neutrons, a detection tube that counts fast neutrons that have passed through the sample without being attenuated to thermal neutrons by hydrogen atoms in the sample, and a detection tube. And an amplifier that amplifies the changed voltage. The number of fast neutrons (hereinafter referred to as RI counts) that have passed through without being attenuated by hydrogen atoms in the sample decreases exponentially in proportion to the amount of water contained per unit volume of concrete. It is possible to measure the unit water amount in concrete from the detected RI count number using the calibration equation shown.

[0005] The positional relationship between the neutron source and the detection tube across the pump line affects the measurement result of the water content, and therefore needs to be always constant. For this reason, in the past, in order to keep the positions of the neutron source and the detector tube constant, an integrated device in which a pump pipe was previously installed in a moisture meter consisting of a neutron source and a detector tube was used for concrete. It has been used as a radioisotope moisture meter.

A conventional integrated radioisotope moisture meter is disclosed in, for example, Japanese Patent Laid-Open No. 7-5 proposed by the present applicant.
As shown in No. 2143, a gamma ray density meter is provided together with a fast neutron moisture meter.

[0007]

However, the integrated radioisotope moisture meter described above has various practical difficulties. That is, it can be attached only to a pump pipe having the same pipe diameter and joint shape as the pipe integrated into the moisture meter. Further, when a boom is used, there is another problem that the pump pipe attached to the boom must be once disassembled to incorporate the moisture meter, and the pump cannot be practically attached to the boom.

[0008] Conventionally, on the premise that the result of density measurement by the density meter is related to the fluctuation of the unit water volume, the measured value of the density meter has been reflected in the calculation of the unit water volume. However, in practice, the density of concrete passing through the pump piping is
Factors other than the unit water amount, such as fluctuations in the ratio of coarse aggregate and mortar, also affect the density of the density meter. Reflecting the problem has a problem that the fluctuation of the unit water volume is largely estimated apart from the actual situation.

Further, the role of the amplifier attached to the radioisotope moisture meter is to amplify a weak voltage generated in the detector tube at the time of detection of fast neutrons to such an extent that the signal / noise ratio can be counted. It is said that it is appropriate to install it at the position closest to the detection pipe (in the same enclosure) to prevent noise on the wiring, but on the other hand, vibration caused by pulsation generated in the pipe when pumping concrete by pumping Is transmitted to the amplifier via the detection tube housing, and the inconvenience of generating noise inside the amplifier cannot be avoided.

Since the noise generated by the amplifier affects the signal for counting fast neutrons, the generated noise is erroneously recognized as the RI count number in the operation part.
As a result, there arises a problem that the measured value of the water content shows a value completely different from the actual unit water content in concrete.

FIG. 6 shows the acceleration of vibration at the time of concrete pumping acting on the radioisotope moisture meter and the generation of noise in the amplifier. FIG. 7 shows an example of a measurement result of a unit water amount in concrete by a radioisotope moisture meter for concrete when affected by noise.

The present invention has been made in view of the above circumstances, and has as its object to enable attachment to a boom pipe, which was impossible with a conventional radioisotope moisture meter, and to provide a pipe diameter. Irrespective of the pump, the neutron source and the detector tube, which constitute the radioisotope moisture meter, can be attached to the pump at a position opposite to the pump while maintaining a constant positional relationship between the two. It is an object of the present invention to provide a radioisotope moisture meter capable of avoiding an increase in fluctuation of noise and canceling noise generated in an amplifier portion due to pulsation during concrete pumping.

[0013]

In order to achieve the above-mentioned object, a radioisotope moisture meter for concrete according to the present invention is provided with a double-girder-shaped rigid frame which can be mounted and dismounted on pump pipes of different diameters. A fastening jig that can be pinched to pump pipes of different diameters attached to the rigid frame part, and detachable on the lower facing side above and below the rigid frame part located at an opposite position outside the pump pipe for pumping concrete. Neutron source that emits high-speed neutrons and a detection pipe that counts high-speed neutrons that have passed through the pump pipe and concrete in the pipe, irrespective of the diameter of the pump pipe due to a change in the clamping angle of the fastening jig. It is assumed that the neutron source and the detection tube can be fixed to the pump pipe while maintaining a fixed positional relationship, and an amplifier in the detection tube is connected to a urethane sponge. Noise generated by vibration during pumping of concrete acting on the pump pipe due to the amplifier section amplifying the weak voltage detected by the detection pipe. Can be canceled.

[0014] Also, high-speed neutrons are provided at the lower edges on both sides of a detection pipe housing for counting high-speed neutrons permeated through the concrete in the pipe mounted on the upper surface of a pump pipe for pumping concrete and on the lower surface of the pump pipe. A neutron source shall be attached to the pump pipe by screws between brackets taken out from both sides of the suspension frame having a groove-shaped cross section provided at the bottom and both upper ends, before and after the detection tube case. A saddle block for piping is integrally provided on the wall, and a jig for clamping the piping is provided on the surface of the saddle block, and the neutrons are adjusted regardless of the diameter of the pump piping by adjusting the clamping angle of the clamping jig. It is assumed that the radiation source and the detection tube can be fixed to the pump pipe while maintaining a fixed positional relationship, and the amplifier in the detection tube is wrapped by a viscoelastic body such as urethane sponge in a three-dimensional state. As being constant, in which the amplifier portion for amplifying a weak voltage detected by 該検 extraction pipe has to be capable of canceling the noise generated due to vibration during concrete pumping acting on the pump tubing.

[0015]

The rigid structure that can be attached to pumps of different diameters to which the neutron source and the detection tube can be attached and detached can be attached to pumps of different diameters by using the attached tightening jig to detect the neutron source and detection. Hold the tubes at regular intervals.

If the non-contact between the neutron source and the detector tube is short, the attenuation of high-speed neutrons in the air is negligible, and there is no problem.

The amplifier under the three-dimensional support insulated from the detection tube housing can cancel the concrete pulsation transmitted to the housing and does not misunderstand the RI count number.

Contribution to the calculation by introducing a gamma ray densitometer is as follows. The density of concrete can be calculated from the amount (formulation) of constituent materials per 1 m ³ , and the density calculated from the composition instead of the value measured by the gamma ray densitometer is used. The use of a gamma ray densitometer was eliminated because the fluctuation of the measured value of the moisture meter became smaller when used. As a result, the fluctuation of the measured value can be reduced.

[0019]

An embodiment of the present invention will be described with reference to FIG.

The girder-shaped three-dimensional frame 1 is divided into two parts by the front and rear joint fittings 2 and 2, and the hand is extended with a hinge 2a arranged at an opposing point of the joint fitting 2 as a pivot point. It can be deployed as described above and can be attached to and detached from the pump pipe 5, and can be deployed as if the hand is spread, and is connected by the connecting fittings 2 and 2 to form a rigid frame. When the hand is extended, the pump pipe 5 can be taken into the frame with a margin. Oscillating arms 6, 6 having tapered portions 6a, 6a are attached to the inner surface of the frame portion 1 with the pins 3, 4 on both sides on the bottom side of the frame as pivot points. 7 are mounted. Thus, a fastening jig is formed by the swing arm 6 and the fastening joint 7.

Therefore, if the arms 6 and 6 are moved toward the pump pipe 5 taken into the frame 1 and tightened by the tightening joint 7, the pipe 5 can be moved regardless of the diameter of the pipe 5.
Is pressed onto a seat 8 arranged on the frame 1. A neutron source 9 is installed on one side of the frame 1 after taking in the pipe 5, and a detection tube 10 is installed on the other side of the fittings 11, 11.
Attach by 12,12.

As is clear from the above, the distance between the radiation source 9 and the detection tube 10 attached to the closed and rigid frame 1 is always constant.

FIG. 2 shows an installation state of the amplifier 13 inside the detection tube 10. The amplifier 13 is a housing 1 for housing the detection tube 10.
0 'and set all around it to urethane sponge 1
By wrapping in 4, the propagation of the impact acting on the detection tube 10 can be eliminated, and the occurrence of noise can be canceled. FIG. 3 shows a result of measuring a unit water amount of concrete passing through the pump pipe 5 by the radioisotope moisture meter having the damper mechanism.

The objects shown in FIGS. 4 and 5 achieve the object without the interposition of a mounting base such as the frame portion 1.

That is, the detection pipe 10 mounted on the upper surface of the pump pipe 5 for pumping concrete for counting high-speed neutrons that have passed through the concrete in the pipe 5 is disposed on the lower edges of both sides of the casing and the lower face of the pump pipe 5. A groove-shaped suspension frame 15 in which a neutron source 9 for emitting fast neutrons is disposed at the bottom.
Brackets 16 and 1 taken out from both upper ends of both sides
It is designed to be attached to the pump piping by screwing between the seven.

Then, saddle blocks 18, 18 for the piping 5 are integrally provided on the front and rear walls of the detection tube 10, and a jig 19 for clamping the piping 5 is provided on the surface of the saddle block 18. I have. The jig 19 is a C-shaped frame 1
A handle 19b vertically mounted rotatably on a key 9a.
And a link claw 19g in which pivot points 19e and 19f are arranged on the elevating block 19d attached to the thread portion 19c and the saddle block 18. By operating the handle 19b, the pipe 5 is held in cooperation with the saddle block 18.

[0027]

As described above, the radioisotope moisture meter according to the present invention is composed of a neutron source, a detection tube, and a holding frame capable of always attaching them to a pump pipe in a fixed positional relationship. , Eliminate the densitometer,
A noise damper for the amplifier is secured in the amplifier, and the concrete pump pipe is installed regardless of the pipe assembled by the site or the boom pipe, and regardless of the pipe diameter. It is possible to measure continuously. Therefore, the quality control level of concrete can be greatly improved by measuring the unit water amount relative to the total amount of concrete using a radioisotope moisture meter at a construction site.

[Brief description of the drawings]

1a and 1b are front and side views of a concrete radioisotope moisture meter according to the present invention.

FIGS. 2A and 2B are plan views for explaining an installation state of an amplifier inside a detection tube, and are vertical sectional views taken along the line AA ′ in FIG.

FIG. 3 is a graph showing a measurement result of a unit water amount of concrete by a radioisotope moisture meter having a damper mechanism.

FIG. 4 is a front view of the radioisotope moisture meter for concrete of the present invention.

FIG. 5 is a side view of FIG. 4;

FIG. 6 is an explanatory diagram of acceleration acting on a pipe and a state of generation of noise in an amplification unit.

FIG. 7 is an explanatory diagram of an example of an influence of a noise on a unit water amount measurement result.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frame part 2 Joint fitting 2a Hinge 3 pin 4 pin 5 Pump piping 6 Oscillating arm 6a Taper 7 Joint 8 Seat 9 Neutron radiation source 10 Detecting tube 10 'Housing 11 Joint fitting 12 Joint fitting 13 Amplifier 14 Urethane sponge 15 Suspension Frame 16 Bracket 17 Bracket 18 Saddle block 19 Clamping jig 19a C-shaped frame 19b Handle 19c Thread 19d Elevating block 19e Pivot point 19f Pivot point 19g Link claw

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshio Yonezawa 1-5-1, Otsuka, Inzai City, Chiba Pref. Inside the Technical Research Institute, Takenaka Corporation (72) Inventor Masao Otake 2--21, Shonai Sakaemachi, Toyonaka City, Osaka Prefecture No. 1 Soil and Rock Engineering Co., Ltd. In-house (72) Inventor Yoshifumi Kumahara 2-21-1, Shonai Sakaemachi, Toyonaka-shi, Osaka Soil and Rock Engineering Co., Ltd. In-house F-term (reference) MA03 NA01 4G056 AA06 DA08

Claims (2)

[Claims] 1. A girder-shaped rigid frame that can be freely deployed and closed on pump pipes of different diameters, and a fastening jig that can be clamped on pump pipes of different diameters attached to the rigid frame. A neutron source for detachably emitting high-speed neutrons on the lower and upper sides of the rigid frame portion, which is a position opposite to a pump pipe for pumping concrete, and a high-speed neutron that has passed through the pump pipe and concrete in the pipe. A neutron source and the detection tube can be fixed to the pump tube by holding the neutron source and the detection tube in a fixed positional relationship irrespective of the diameter of the pump tube by a change in the clamping angle of the fastening jig. At the same time, the amplifier in the detection tube is fixed in a three-dimensional state wrapped with a viscoelastic body such as urethane sponge, and the weak voltage detected by the detection tube is amplified. A radioisotope moisture meter for concrete, wherein the amplifier portion can cancel noise generated due to vibration during pumping of concrete acting on the pump pipe. 2. High-speed neutrons are disposed on the lower edges of both sides of a detection pipe housing for counting high-speed neutrons permeated through the concrete in the pipe mounted on the upper surface of a pump pipe for pumping concrete and on the lower surface of the pump pipe. A neutron source shall be attached to the pump pipe by screws between brackets taken out from both sides of the suspension frame having a groove-shaped cross section provided at the bottom and both upper ends, before and after the detection tube case. A saddle block for piping is integrally provided on the wall, and a jig for clamping the piping is provided on the surface of the saddle block, and the neutrons are adjusted regardless of the diameter of the pump piping by adjusting the clamping angle of the clamping jig. It is assumed that the radiation source and the detection tube can be fixed to the pump pipe while maintaining a fixed positional relationship, and the amplifier in the detection tube is wrapped with a viscoelastic material such as urethane sponge.
A radio for concrete in which an amplifier part for amplifying a weak voltage detected by the detection pipe can cancel noise generated due to vibration during pumping of concrete acting on the pump pipe as a one fixed to a three-dimensional state. Isotope moisture meter.