JPH029956A - Ceramic plunger for reciprocating pump - Google Patents

Abstract

PURPOSE:To absorb thermal expansion and prevent the damage of a ceramic plunger by fixing a ceramic sleeve to a driving member via a fixing means and forming a space between the fixing means and the ceramic sleeve. CONSTITUTION:A ceramic plunger 12 is constituted of a fixing metal 16 fixed at the tip section of a tappet 15 reciprocated by a crank motion mechanism not shown in the figure, and a ceramic sleeve 18 fixed to a flange section 16a formed on the periphery of the fixing metal 16 by a fixing means T made of a bolt. A thermal deformation absorbing space S is formed between the outer periphery of the fixing means T and the inner periphery of the ceramic sleeve 18. The thermal expansion of the fixing means T and the ceramic sleeve 18 is absorbed by the thermal deformation absorbing space S respectively, the damage of the ceramic plunger 12 is prevented, durability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a ceramic plunger for a reciprocating pump.

(Prior art) Reciprocating pumps for transporting and filling liquid foods and chemical solutions have cylinders and plungers made of stainless steel for hygiene and chemical resistance, but they wear quickly and have problems with durability, as well as wear and tear. To prevent powder from getting mixed into the feed fluid, some cylinders and plungers are made of at least the plunger, which is made of ceramic, which has extremely low wear.

As a plunger made of ceramic, there is a known structure in which a enamel (ceramic) layer is formed on the outer peripheral surface of the plunger, as shown in Japanese Utility Model Application Publication No. 51-80703, for example. There is.

(Problems to be Solved by the Invention) In the structure described in the above publication, the ceramic layer, which has almost no toughness and is brittle, is in close contact with the outer peripheral surface of the metal plunger, making it difficult to feed high-temperature fluid. When the plunger thermally expands due to heat transfer from the plunger drive source and frictional heat during sliding between the cylinder and plunger, the ceramic layer has extremely little thermal expansion, so this difference in thermal expansion may cause cracks in the ceramic. , it may peel off.

In addition, if the pump is operated without fluid reaching the pump, such as when pumping up and feeding low-temperature fluid from a low position, the ceramic layer may be damaged by the frictional heat generated by the sliding between the cylinder and the ceramic plunger. When the temperature rises, low-temperature fluid is sucked in and the high-temperature ceramic layer is rapidly cooled down. This sudden temperature change (so-called heat shock) can cause the ceramic to crack or peel. There was a problem with durability.

The present invention was proposed in view of the above-mentioned problems, and it prevents damage to the ceramic plunger due to temperature differences and heat shock and enables a reciprocating pump to operate continuously for a long time. The purpose is to significantly improve the durability of the pump.

(Means for Solving the Problems) In order to achieve the above object, a reciprocating pump plunger according to the present invention includes a ceramic plunger that slides inside a cylinder at the tip of a tappet that is reciprocated by a crank motion mechanism. In reciprocating pumps that are removably attached, the ceramic plunger is fixed to the sleeve mounting part formed at the tip of the tappet, the barrel part is formed into a cylindrical ceramic sleeve, and the ceramic sleeve formed inside the ceramic sleeve is fixed to the sleeve mounting part. It consists of a fixing means that is clamped and fixed between the metal fittings, and
A space for absorbing thermal deformation is formed between the inner peripheral surface of the ceramic sleeve and the outer peripheral surface of the fixing means.

(Function) When the fixing means expands in the radial direction of the ceramic sleeve due to the frictional heat due to sliding with the cylinder, the heat of the feeding fluid, and the transmitted heat from the plunger drive source, the expansion is made into a space for absorbing thermal deformation. Therefore, it does not act on the ceramic sleeve, which has almost no thermal expansion, and reliably prevents J5 scratches on the ceramic sleeve due to the difference in thermal expansion.

Furthermore, even if the ceramic sleeve undergoes heat shock and expands or contracts in its radial direction, this change is absorbed by the thermal deformation absorbing space, thereby reliably preventing damage to the ceramic sleeve due to heat shock. .

(Example) Embodiments of the present invention will be described below based on the drawings.

As shown in FIG. 1, the horizontal reciprocating pump 1 includes a crank motion mechanism 3 provided on the right half of the casing 2;
The crank motion mechanism 3 consists of a pump section 4 formed on the left half and a valve device 5 attached to the left end of the casing 2, and the crank motion mechanism 3 rotates a human power shaft 6 by a drive device (not shown) such as an engine or a motor. When driven, the rotation is decelerated by the gear reducer 7 and transmitted to the crank arm 8, causing the large end of the connecting rod 9 to move in a circular motion, thereby reciprocating the piston 10 connected to the small end to the left and right. It is composed of

The pump section 4 includes a cylinder 11 that is fixedly supported by the casing 2 and a ceramic plunger 12 that slides back and forth within the cylinder 11.
4 provides an airtight seal between the plunger 12 and the cylinder 11.

As shown in FIGS. 1 to 3, this ceramic plunger 12 has a fixing metal fitting 1 defined by screw fitting on the tip of a tappet 15 extending from the left end of the piston 10.
6, and a ceramic sleeve 18 which is fixed by a fixing means T consisting of bolts 17 (fixing fittings) while in contact with a substantially brim-shaped sleeve mounting portion 16a formed on the periphery of the fixing fitting 16. There is.

The barrel portion 18a of the ceramic sleeve 18 is formed into a cylindrical shape, and an M plate 20 having an insertion hole 19 through which the bolt 17 is inserted is fitted on the left end surface.

In the ceramic sleeve 18 configured as described above, the bolt 17 is inserted through the insertion hole 19 with the right end thereof in contact with the sleeve mounting portion 16a of the fixing metal fitting 16, and the threaded portion 17a is inserted into the screw hole 16b of the fixing metal fitting 16. When the bolt 17 and the sleeve mounting portion 16a are screwed together and fixed between the bolt 17 and the sleeve mounting portion 16a, a space S for absorbing thermal deformation is created between the outer circumferential surface of the fixing means T and the inner circumferential surface of the ceramic sleeve 18 inside the ceramic sleeve 18. is formed.

This thermal deformation absorbing space S is created by the ceramic sleeve 18 and the backing 1 of the cylinder 11 when the pump 1 is driven for a long time.
4, receiving frictional heat from sliding between them and heat from high-temperature fluid,
Due to the heat transmitted from the crank motion mechanism 3, when the fixing means T thermally expands in the radial direction of the ceramic sleeve 18, the thermal expansion is absorbed and the fixing means T is reliably prevented from acting on the ceramic sleeve 18.

Further, even when the ceramic sleeve 18 expands or contracts in the radial direction due to heat shock, the thermal deformation absorbing space S absorbs the change, and the ceramic sleeve 18
This will ensure that damage to the equipment is prevented.

In the above embodiment, the backing 14 provides an airtight seal between the cylinder 11 and the ceramic plunger 12. However, the cylinder 11 is made of ceramic, and the ceramic plunger 12 directly contacts the inner circumferential surface of the cylinder 11. Alternatively, the gasket 14 may be omitted, or the center portion of the fixing fitting 16 may be made to penetrate the ceramic sleeve 18 and protrude outside the left end in place of the bolt 17, although not shown. It goes without saying that the fixing means T may be constructed by fitting a stop ring to this protruding portion.

(Effects of the Invention) As described above, according to the present invention, the space for absorbing thermal deformation provided between the fixing means and the ceramic sleeve located on the outer periphery of the fixing means is expanded by the thermal expansion of the fixing means and the ceramic sleeve. Since it absorbs the difference, it is possible to operate a reciprocating pump for a long time without damaging the ceramic sleeve, and it can also be used as a pump for delivering high temperature fluids.

Moreover, when the ceramic plunger expands and contracts in its radial direction due to heat shock, the thermal deformation absorbing space absorbs the deformation, preventing damage to the ceramic plunger due to heat shock and greatly improving durability. The advantage is that it can be done.

[Brief explanation of the drawing]

Figure 1 is a partially cutaway side view of a horizontal reciprocating pump;
The figure is a vertical sectional side view of the ceramic plunger portion, and FIG. 3 is an exploded perspective view thereof. DESCRIPTION OF SYMBOLS 1... Reciprocating pump, 3... Crank motion mechanism, 12... Ceramic plunger, 15... Tappet, 16... Fixing metal fittings, 16a... Sleeve mounting part, 18... Ceramic Sleeve, 18a...
Barrel part, T...fixing means.

Claims (1)

[Claims] In a reciprocating pump, a ceramic plunger that slides inside a cylinder is removably attached to the tip of a tappet that is reciprocated by a crank motion mechanism. It consists of a ceramic sleeve formed into a shape, and a fixing means formed within the ceramic sleeve to clamp and fix the ceramic sleeve between the sleeve mounting part and the fixing fitting, and the inner circumferential surface of the ceramic sleeve and the outer circumference of the fixing means. A ceramic plunger for a reciprocating pump, characterized in that a space for absorbing thermal deformation is formed between the ceramic plunger and the surface.