JP2594982B2 - Lining method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention suppresses the amount of latence generated when lining the inside of a pipe rotating at a medium / low speed with a gravity multiple of 20 or less with cement mortar. The present invention relates to a lining method for preventing dripping.

<Conventional technology and its problems> In order to line cement mortar on the inner surface of a conventional steel pipe or cast iron pipe, the cement mortar is evenly sprinkled on the inner surface of the pipe, and then the pipe is usually subjected to a gravity multiple of 20 or more (40 times or more).
(The front and back are common) and a method of rotating the cement mortar strongly and centrifugally pressing the inner surface of the pipe was adopted. However, such a centrifugal force having a high gravity multiple, that is, a high centrifugal force, particularly in order to act on a large-diameter pipe, involves complicated steps such as the need to attach a reinforcing tire for preventing bending of the pipe, Problems such as the occurrence of personal injury occur due to noise pollution or popping out of pipes due to vibration. In order to solve this problem, a method of centrifugal molding at a low speed using calcium aluminate and gypsum has been proposed. However, a practical problem has arisen due to adjustment of the setting time of cement mortar (Japanese Patent Publication No.
-25569).

As a result of various studies by the present inventors to solve the above problems, the cement mortar sprinkled on the inner surface of the pipe adheres to the inner surface of the pipe even at a low speed rotation, and the cement mortar is streaked with time. To make a cement mortar lining pipe that does not cause so-called sagging, cement mortar mixed with a specific cement hardening accelerator is lined at low speed, so that there is little latence, no cement mortar occurs, and long-term stable cement mortar The present inventors have found that a mortar lining tube can be formed, and have completed the present invention.

<Means for Solving the Problems> That is, the present invention uses a cement mortar containing a cement hardening accelerator composed of aluminum sulfate and an alkali metal sulfate, and attaches the cement to the inner surface of a pipe rotating at a gravity multiple of 20 or less. This is a lining method for the inner surface of a pipe, which is characterized by chopping mortar.

 Hereinafter, the present invention will be described in detail.

As the cement according to the present invention, any of various portland cements and various mixed cements can be used.

The cement hardening accelerator used in the present invention (hereinafter referred to as "accelerator") is composed of aluminum sulfate and alkali metal sulfate.

As the aluminum sulfate (hereinafter, referred to as aluminum sulfate), any of an anhydride and a hydrate (for example, Al ₂ (SO ₄ ) ₃ .12 to 18H ₂ O) can be used.

The particle size of Al sulfate is preferably 0.5 mm or less, more preferably 0.25 mm or less.

As the alkali metal sulfate (hereinafter referred to as an alkali salt) to be used, there are sodium sulfate and potassium sulfate (hereinafter referred to as sodium sulfate and K, respectively), which can be used in combination. Usable alkali salts can be used, but use of sodium sulfate is preferred in view of workability and strength development.

The proportion of the accelerator used is 0.5 to 100 parts by weight of cement.
It is preferably 7% by weight, more preferably 1 to 5 parts by weight. 0.
If the amount is less than 5 parts by weight, there is no initial setting promotion effect, and if it exceeds 7 parts by weight, the setting of the cement is promoted and problems such as workability arise.

The ratio of the use of the alkali salt to the aluminum sulfate is
It is preferably at most 2 times the weight of Al. When the amount exceeds 2 times by weight, the initial setting is delayed, and the initial strength expression is deteriorated.

As a method of mixing the accelerator, 1) the cement is mixed in advance with the cement. 2) Mixing at the time of kneading cement mortar (hereinafter referred to as mortar). 3) Add arbitrarily after kneading the mortar, for example, within one hour. 4) Mix the accelerator as a slurry. And so on.

In the present invention, a setting regulator (hereinafter referred to as a regulator) may be used in combination.

Inorganic compounds such as boric acid, phosphoric acid, fluorinated compounds and salts thereof, citric acid, tartaric acid, oxycarboxylic acids such as gluconic acid and salts thereof can also be used in combination as regulators.

Further, if necessary, it is preferable to use a commercially available cement water reducing agent, for example, a salt of β-naphthalenesulfonic acid formalin condensate, a melamine sulfonate, or the like, from the viewpoint of increasing strength.

As the mortar, an arbitrary amount of fine aggregate and water are blended with cement and an accelerating material to form a kneaded product, and the mortar can be centrifugally formed (for example, a flow value of 180 to 280 mm). In addition, commercially available cement expanders such as calcium aluminate and gypsum are used as the above-mentioned materials.
By mixing CSA or the like, it is possible to improve the adhesion between the mortar and the steel pipe or the like and the long-term stability of the mortar.

The proportion of each of these materials used is 100 parts by weight of cement; 0.5 to 7 parts by weight, preferably 1 to 5 parts by weight of cement hardening accelerator; 15 parts by weight or less, preferably 5 to 10 parts by weight of cement expander.
Parts by weight; 100 to 500 parts by weight of fine aggregate, preferably 150 to 300 parts by weight; water 30 to 300 parts by weight, preferably 40 to 70 parts by weight.

As a kneading method, all the materials may be mixed at once, or a cement hardening accelerator may be added at an arbitrary time after kneading the mortar, preferably within one hour. The mortar kneaded in this manner is evenly sprinkled on the inner surface of the pipe, and the gravity multiple is 20.
In the following, centrifugal compression is performed. The thickness thereof is not limited, but is preferably about 3 to 20 mm.

For molding, mortar is sprinkled in a tube rotating at low speed,
After uniforming the surface with a bar, medium speed, for example, gravity multiple 20
Hereinafter, if it is performed preferably within 8 to 15 and within 60 minutes, preferably within 30 minutes, and then terminated, the centrifugation time is not particularly limited.

By steam-curing the mortar-lined pipe lined in this way, there is an effect in charge of the sled.

Furthermore, it can be used for the production of concrete fume pipes by mixing coarse aggregate and the like into concrete.

<Example> Next, the present invention will be further described with reference to examples.

Example 1 93 parts by weight of ordinary Portland cement (manufactured by Denki Kagaku Kogyo Co., Ltd.), 7 parts by weight of the accelerator shown in the table, 230 parts by weight of fine aggregate (Natural sand from Himekawa FM = 2.7), and 53 parts by weight of water were kneaded. Mortar.

Next, the mortar was sprinkled on an inner surface of an iron tube having an inner diameter of 255 m / m and a length of 500 m / m at a thickness of 2 cm and a weight of 1.3 kg.
Centrifuged at 12 for 10 minutes. The lined tube was left in a room, and the dripping and tightness of the mortar and the thickness of the latence were examined. However, in Experiment No. 12, centrifugation was further performed at a gravity multiple of 40 for 5 minutes.

<Materials> Sulfuric acid Al: Daimei Chemical Co., Ltd.Na sulfate: Asahi Glass Co., Ltd. As can be seen from the table, according to the method of the present invention, the generation of mortar reitance is suppressed, and nobody is generated even by low-speed centrifugation.

<Effects of the Present Invention> According to the present invention, the following effects can be obtained.

1) Even in low-speed centrifugation, the cement mortar does not form streaks with the passage of time, that is, so-called dripping does not occur.

2) The occurrence of latency is small, and it does not peel off even if a seal coat is applied after polishing.

3) Low noise.

4) The wastewater treatment is easy with less slag generation.

5) It can be used in combination with a high-performance water reducing agent that cannot be used conventionally.

6) The mortar has good long-term stability.

7) Vibration of the pipe is eliminated, and accidents such as popping out of the pipe can be eliminated.

Claims (1)

(57) [Claims] 1. A pipe inside a pipe, wherein a cement mortar containing a cement hardening accelerator composed of aluminum sulfate and an alkali metal hydrochloride is used, and the cement mortar is sprinkled onto the inner surface of a pipe rotating at a gravity multiple of 20 or less. Surface lining method.